LOL... I'm sure I missed some info or could have explained better, but thank you! =)

I hope you realize that my voice to text put in rancher when I meant wrencher... Hahaha

Caleb Lea Thank you for the kind words & the sub! I can't spend much time talking about what is going on, since I'm recording while I'm at work. Adding more information during editing adds time, so I keep my edits as short as possible. I answer / reply to all comments. so if you ever have questions... feel free to ask. Finding a trades school that offers an Automotive training program can be a good start / of help before finding an actual place that will take you on as an apprentice, but you can start working at an automotive shop without Post Secondary training. You'll be going through an apprenticeship anyways... you work and then go to school, work and then go to school. My apprenticeship was 4 years... theory you learn in school is great, but what you learn on the job they can't teach in school.

Service manuals are helpful... you can download as many as you want, for as many VW's as you want, for $35 USD from erwin.vw.com/erwin/showHome.do $35 is a 24hr subscription, within that time you can download what you need. The PDF files do not expire.

Thank you for sharing your DIY success... it's nice to hear that one of my videos was of help to someone. Thank you for watching!

I can't find your address... I wrote it on a piece of paper and can't find it. If you could, send it again to: fkh161@fkh161.ca

+Brad Sherwin Thank you very much... that is nice to hear! If you ever have any questions, feel free to ask... I try to reply as quick & as best as possible.

Good job sticking with it... best way to get to know your car!

LOL

Thanks for watching & sharing your DIY experience!

+Stuart Barley Thank you... we will see what happens / where youtube takes me.

Thomas EXOVCDS You

Thank you... kind of you to say. Keep in mind that this video is for VW A4's (4th generation of the A Platform... Golf & Jetta). Your Audi "A4" is of the Audi B Platform, where generations are B5,B6,B7 etc. Yes, modern BMW's see to have a lot of oil leak issues. That's why I drive 30 year old BMW's. =) Thank you for watching!

Nice to hear that my videos have been of help... thank you for watching!

Thank you... but my POV videos take time to get used to, your views might change. :)

Thank you for watching.

I have a VW Golf gti 1997 2.0 automatic

@@LAEdgar 97 mk3's don't have water pump impeller problems. Check your thermostat. You can check for coolant flow "into the reservoir bottle" (via the small return hose). If there is flow, then the water pump is OK. If there is no flow... remove the hose and blow into it. If you can NOT blow into it, then the hose is plugged or the fitting at the head is plugged. If you CAN blow into it AND there is no flow into the reservoir bottle.... then it "could" be a water pump problem.

@@LAEdgar If the temperature needle stays in the MIDDLE... then it is NOT an overheating issue. Either a faulty coolant reservoir "level" sensor or a problem in the dash.

Thank you for watching!

Thank you... but what did you mean with your earlier comment?

Thank you for watching!

Thank you and thank you for watching! If you have specific questions or need specific information, let me know. I don't always post "installation" videos, but I can answer any questions you might have... or at least I try to answer as best I can.

Thank you and thank you for watching! Send me your mailing address and I'll send you some of my channel stickers. fkh161 @ fkh161 .ca (no spaces)

I have your address, thank you. I removed your comment. I will send stickers this week!

+Joe Blow I'm still learning... Thank you for watching!

+Michael Shone I think it was 123K km

+Pablo A Thank you!

Thank you and thank you for watching!

Thank you for watching... let me know what your mechanic finds. Here's a Beetle video: kzfaq.info/get/bejne/otRkmtWKypm7nnk.html

Im so piss rigth now the mechanic is charging me 1800 for replacing all the part but also telling me that they haven't fix the overheating problem.same reason i brought the car to them

+Garth Goldberg New to-us customer... I'm quite sure that the pump is original. Belt "could" have been replaced at some point, but I doubt it. It looked pretty good considering. I didn't get much info from the boss and not sure if he bothered asking for repair history. Once we know what we need... we stick with that.

lol

@@EXOVCDS wwalli.g out in 4 min I swear I'm up

Thank you for watching.

Let me know what your results are or if you need further help.

The cooling system filler is a Snap-On unit, but similar to this: www.uview.com/index.cfm?dsp=productdetail&id=45700&productid=5120 It is NOT required to fill / bleed an engine, but can make life easier. As long as the coolant return hose (to the reservoir) is clear and the water pump is good... there should not be any issues with bleeding / filling a system the old fashioned way.

Thank you sir. 👍

thank you for watching!

Thank you for watching!

+Billy P. Got it.

+tipptop9 I've seen those flimsy looking pumps... not very impressed with them.

+Thomas EXOVCDS I was surprised to be honest because contitech have a good name here the same as gates if not better. Maybe it was the tensioner that was made in Canada now that I think back, will be buying gates in future or at least getting the water pump separately.

It's just a usb extension cable... thanks for watching!

Thank you for the kind words and subscribing! Send me your mailing address and I'll send you some channel stickers!

+rhkips I know, right!? Thanks! Anything more technical and I would have to refer you to a couple of other automotive channels! :)

Most likely thermostat... unless your fans don't work due to a bad fuse (but then the car should be fine while driving at cruising speeds / only overheat when not moving).

@@EXOVCDS fans work for sure already checked them and it's even on the highway

@@Michael-uo4jj yeah, thermostat then.

There might be an issue with a temperature sensor not activating low speed. The fans should be pulse width operated... meaning that the ECM will send a signal to the fan module to turn the fans on, at whatever speed needed. There might be a problem with a coolant temperature sensor... check the engine & other modules for fault codes. If temperature is ok while cruising, it's not a thermostat issue and the radiator is not restricted. Level is ok to be a little above max. Under pressure, the level might come down a little. Air in the cooling system "should" bleed itself out into the reservoir bottle, as long as the small return hose at the reservoir is not plugged.

Thank you for watching!

Test the fans directly at each connector (apply power & ground). I bet that your large fan is no good and that your small fan "low speed" is burnt out.

Neither of my fans turn on either, no matter how hot it gets but they both come on when I turn the air conditioning or the heat on. The fuse is good as well. However, when I remove fuse 16 inside the car, the fans come on immediately. I assumed that this was a thermostat problem.

+James James How hot / warm is the lower rad hose?

James James

Gerald Teague I doubt he will reply back.

The overflow tube is an air bleed hose... so blowing into it (for testing) is not an issue, as the air will be pushed back out once the engine is running (as long as the water pump is OK and there are no restrictions in any of the bleed hoses / fittings). kzfaq.info/get/bejne/gNSEiNVhuKuucqs.html

@@EXOVCDS thanks man. I love people like you who do effective things. Instead of running in circles. Thanks for the insight. If you ever need to learn how to wheelie a motorcycle, message me 🤣.

The thermostat is probably bad. kzfaq.info/get/bejne/fbNmed1zsrS1eZc.html

Part 1: kzfaq.info/get/bejne/bK6Skt2m2dqwoXk.html Link to part 2 is in the description.

Head gasket can cause air pockets that interfere with coolant circulation. Test / check for combustion gases in the cooling system. The pump impeller can be checked by removing the thermostat.

Thomas EXOVCDS- really appreciate the reply. I am trouble shooting tomorrow. Thanks

All right trouble shot the water pump as per your video and its flowing at idle and ~4000 rpm so if it is slipping I couldnt tell. That being said the amount of fluid flowing didnt seem to change much at different rpms. The engine reached over 90 degrees (past mid point) and the fans never turned on. I let it run like that for 10 mins and the lower rad house remained cold. Am I right to suspect the thermostat is failed closed? Is the sensor for the fans on the lower portion of the cooling system? Thanks again, I plan to buy you a coffee :)

Craig D What year car & engine... I might have missed that. Pull the tgermostat... if the water pump is next to it (1.8t, 1.9 TDI, 2.0L) then you can check the impeller by trying to move it with your fingers. If the pump feels fine / does not move, install a different thermostat.

Craig D 1.8t and TDI engines sometimes have restrictors in the return hose at the reservoir. Flow should definitely increase when comparing idle to 3000+ rpm.

Let me know who it goes / went.

Went great, no more overheating!

Thank you for the update!

Cabin heat should be stable (hot when in hot position) no matter radiator condition / flow. I'm not familiar with this engine (or vehicle)... any prior work / service that lead up to this issue or did this just surface one day? Inconsistent heat is usually a water pump or head gasket issue (providing that the cooling system was initially free of air / combustion gases). The radiator has an IN & OUT hose... disconnect the IN hose from the radiator and point it into a container. Start the engine and hold the revs at 2000 (add coolant to the reservoir as the fluid level drops) to gauge the flow of coolant. Turn the engine off. reconnect the hose. Remove the OUT hose and do the same thing... if flow out of the radiator is LESS (fluid level does not drop as quickly in the reservoir) then the radiator is restricted.

Yes... depending on how severe the overheating was, head gasket or other components might fail / surface at a later time. Always install a complete kit (pump, belt tensioner etc).

If you have a leak, you need to fix the leak first. If it is leaking because it's overheating, you need to figure out why it's overheating. Do you have heat inside the car? No heat inside the car could be because of a bad water pump. If the radiator is not getting hot, then the thermostat is stuck closed. With AC ON, the radiator fans should be running, if NOT, then there might be a problem with the fans.

Directed at whom? No fan clutch on these 2.0L VW engines (A4 platform).

When was the last timing belt & water pump change? The thermostat would be the cheaper repair to start with. If that does not solve things, the water pump may have to be next. A thermostat that is not opening fully, can restrict coolant flow under higher rpm / load... but be OK at lower engine speeds (because TDI engines don't produce as much heat as gasoline engines).

@@EXOVCDS many thanks for the response. The engine was fitted as last one got damaged. So new engine was probably stripped to the bone and may be a possibility that timing belt and water pump were used from the older engine, that is going to be checked later on this week. But I will do that and change thermostat first. The old pd engines head gasket would become porous and even though it gave none of the typical symptoms it would actually be the head gasket that was the issue on them. But this car is a 2.0 TDI common rail engine, head gaskets have been made very well by VW and they very rarely go

@@keyman-hk7hv ok, let me know what happens after changing the thermostat.

@@EXOVCDS will do. Many thanks

@@EXOVCDS Hi Thomas, changed the inline thermostat with no luck and genuine water pump and timing belt kit seat Alhambra 2013 diesel still overheating at highway speeds. Have not changed main thermostat but mechanic here is saying he's tested sensors etc and does not think it's main thermostat. What should oil temperature when car is being driven? As I have realised that the car will not show it's overheating until the oil temperature doesn't read 116 degrees. Do you think this can be linked?

Year, make, model, engine? Engines usually don't overheat in a couple of minutes, even when the water pump is not pumping. Head gasket?

Replace the large fan... it is most likely burnt out. BOTH fans should come on when the radiator gets hot or when AC is turned ON. The fact that the little one works, tells me that the fuse is OK. BOTH fans use the same fuse. Unless there is a wiring problem with the large fan, the fan is most likely bad. Here's a video for replacing the large fan (for a 1.8T), yours will be easier.kzfaq.info/get/bejne/iKpnY9hzxK_OmWg.html

Did you check fan operation like in this video? Is the lower radiator hose getting hot? Does the heat inside the car go away when the car starts to overheat? If temperatures only spike when you are NOT moving, then it is an electrical / radiator fan issue. If it also spikes while at cruising speeds, then it is either a water pump issue or a thermostat issue (more likely water pump). Overheating an engine that badly, will result in a head gasket failure... and all plastic coolant pipes / connections / flanges (including the radiator) will have been stressed & weakened by the overheating... so they will be prone to early failure.

+mi lu The one I installed has a metal impeller: instagram.com/p/BDEOBMTFDao/ instagram.com/p/BDEOP8GFDbM/ The "new style / type" of plastic that is uses is "supposed" to be better. We install plastic or metal... depending on what comes in the kit.

Coolant is always circulating even when the thermostat is closed... since the water pump should always be pumping. So yes, you should have fluid flowing back into the reservoir right away... at any temperature.

Thank you very much for your quick response. Now, it's looks as though the severe overheating issue I experienced yesterday was caused by a water pump failure which, as you suggest in your video, may have also caused the thermostat to stick in the closed position.

If you have no heat inside the car (heat goes away when blower is on high speed)... that is another indicator that the pump is not pumping coolant.

Cheers for the additional info. BTW, love Rush - Spirit Of Radio (Permanent Waves, 1980)

You can mark the belt & pulleys and transfer the marks to the new belt. Whichever way you would like... if you get it wrong, the engine will run rough... if you get it really wrong, then the engine will bend valves.

+Yanier Olivera I will have to listen for it. Haha

You need to check your thermostat operation... the reservoir cap blew off because of too much pressure from too high a coolant temperature (there's a needle & warning light that usually warn drivers that the engine is running warm). Although you need to fix the leaks (coolant flange) first, to determine if there is anything else, I would replace the thermostat right away anyways (because of how hot the system got to blow that cap off). The good news is that you have coolant circulation (water pump is OK). Watch this video for thermostat removal: kzfaq.info/get/bejne/ftB8bLNmyMDbZps.html Watch this one for coolant flange: (New Beetle 1.8T, but similar) kzfaq.info/get/bejne/kLSEeZCEtKqpd2g.html Once you have the new flange in your hand, you can determine what needs to be removed to replace it / get access to it.

@@EXOVCDS I appreciate the advice, man. Is it possible the leak is coming from the oil pan think it's called? I still haven't been able to locate exactly where the leak is coming from. It's dripping from the bottom most part, the big metal casing though the oil isn't leaking. I'm not sure if it's the source of the leak or it just happens to be running off of it. The upper left hand side radiator hoses aren't leaking anything, the upper and bottom right hoses aren't either, I believe. If you want, I can try to uploading a pretty short video or two panning under the hood and underneath the car, though I'll be limited because I don't have any jacks or great video quality.

@@smolhatshapuru7552 could be the water pump... remove the splash guards under the engine (if there are any) and look for dried coolant behind the crankshaft pulley. A leaky pump will cause coolant to drop out from behind there and the coolant will run along the oil pan as well. Any repair shop should be able to find the leak quite quickly... they might charge you 1/2hr to check it, but in some cases that can be cheaper than the time lost trying to find it yourself. Fixing the leak is one thing, you may still need to determine what the cause for overheating is (if it still does it).

@@smolhatshapuru7552 Example of fixing a leak and then finding that there is another problem. kzfaq.info/get/bejne/etuXhddnxNOliXk.html

Thanks... but I doubt it. Prank videos is where it's at. There are guys getting 1 million views per day. That's a good $1000+ per day of income! Guys that actually work for a living and do KZfaq part time will never get there.

+Thomas EXOVCDS I think great things can be achieved by mixing things up a little bit and breaking from tradition. Original content is where it's at. If you just happen to fall off something of explode something in the process then you're onto a winner. Look at MightyCarMods they get gazillions of views just for tinkering with cars. I'm sure there's an original project out there that can compete....

+Badgertronix Yeah... I'm sure the possibility is there, but as long as I have a day job, I don't think I can expand or change the format.

+Thomas EXOVCDS Work smarter not harder.... there must be a way to achieve that

+Badgertronix If in doubt... marry someone rich! LOL

Can you post / upload a video of what you mean by "boiling off" at the expansion tank? If you are talking about fluid dripping from the "vent", remove the reservoir cap and make sure that the o-ring is sitting correctly in the cap. If the o-ring is in place, then you need to check of excessive pressure that is causing the cap to vent. A bad head gasket can cause excessive pressure without coolant coming out the tailpipe or oil in the cooling system.

@@EXOVCDS, boiling off I mean the coolant starts to boil rapidly in the tank, almost forcing the cover to open up. When you shut the engine off, you still hear and see the coolant boiling. Afterwards, the entire tank becomes empty.

@@pauliroha5506 What coolant mixture are you using? Only water?

@@EXOVCDS vw g12 coolant

@@pauliroha5506 What ratio? 50/50? Shouldn't be boiling at 97c. I'd still check for excessive pressure.

+Daniel Madrigal I know, right!? Sometimes I play chicken with the rad fans... I start spinning them with my hand to see how close I can get to the activation point! LOL

+Thomas EXOVCDS Haha I've done it my self too!! Fun game!

Metal or plastic water pump impeller? Could be a loose impeller on the pump. Could be an issue with the temperature blend door or sensor. Use a scan tool to monitor / check blend door position and temperature sensor values (for the different vent positions). Run basic settings of the flap motors... unless your system is cable operated, then check for correct operation of the blend doors visually from under the dash. TDI engines will have a cold lower radiator hose for a long time (thermostat takes a long time to open). Once you drive the vehicle, the radiator & lower hose get cold again quick... so that does not always mean bad thermostat or water pump. As long as the temperature needle doesn't move past the middle (90c / 190F), the water pump & thermostat should be OK. The heater core is of an open circulation design like the mk4's (if I recall correctly)... meaning there should always be flow. Feel the heater core hoses to see if they are the same temperature. Car is safe to drive as long as the temperature needle doesn't go past the middle. Use AC to defog the windshield.

No... you will still have heat, just not as strong and as fast as when the thermostat is working correctly.

Very common. =)

Some people need hand holding! LOL Thank you for watching!

How late? Year, model, engine?

When the engine is running, reservoir / coolant cap off... can you see coolant flowing back into the coolant reservoir from the small return hose? The faster the engine rpm, the harder the stream of coolant coming out?

I'm not sure what else to do, any advise?

@@fendersrage Confirm that the temperature gauge is actually accurate. Compare ECM coolant temperature with Instrument Cluster temperature via ECM & Cluster control modules. Using a scan tool, activate instrument cluster output tests... this will "swing" the needles left/right and make them stop in the middle. If there is a problem with the needle / driver, then the temp needle will not match the movement of the other needles. One or two electric fans? Year & model of car?

If the temperature comes down when the A/C is on, then the thermostat is ok. Check the condition of the fuse on top of the battery and the radiator thermal switch at the side of the radiator below the battery: kzfaq.info/get/bejne/iNWYabV02J6tep8.html

Thomas EXOVCDS checked out the fuse and replaced the thermal switch still nothing I'm stumped on this one. Fans still won't kick on unless I put on a/c

Do you have heat inside the car?

Do the fans come on when you manually bride low speed at the radiator fan switch wiring harness plug? If no, does one of the wires have battery power? Does the radiator get warm?

You have a KZfaq account. Post a video.

Especially when it's a hard to reach thermostat!

Post a video so that I can see how & where you are checking for flow. If not enough coolant is in the system, it can not push coolant back into the reservoir... and not enough heat from the heater core.

@@EXOVCDS I lied, my return line was plugged so I remedied that and my heat works, at least intermittently . Pretty sure heater core is leaking and that is my last issue. Was really hoping I could avoid that. Thanks for the reply and keep up the good work!

@@johnnyceagles thank you for the update!

gracias y gracias por mirar!

Coolant spills with reservoir cap on?

@@EXOVCDS Yes Boss the reservoir cap is on and tight. The Coolant spill via the pressure release. I also didn't mention that I replaced the seal where the coolant pipe connects to the thermostat housing recently. Thanks for taking time to respond. Grateful. I didn't mention that

And again from the pattern noticed yesterday, I had to open the thermostat housing and saw that the 87 Degrees was stuck open. No spring found..... Am going to replace the set today once am able to get it and hope it solves the problem. I have used the car for 1 year without any issues and no mech had touched it. Simply means that the old user's mech had tampered with it #Sad Your videos have been of great help. Will update every one once am done

It is most likely a head gasket issue... steel seal (or any stop leak product) can only do its job when it gets to the leak and is able to seal it. A lot of time, the sealant never makes it to the problem area... or it plugs up different areas. We don't use any type of stop leak powders or liquids. Run the engine up to temperature with a bit of harder load (radiator hoses will feel very firm if a head gasket issue is present). Allow the engine to cool off over night. If a head gasket issue is to blame, the pressure in the cooling system will remain over night(in most head gasket cases). If the hoses are still solid / firm the next morning, it's time to pull the cylinder head. There are other ways to check for head gasket issues... best one being checking for combustion gases in the cooling system.

Thank you ever so much for your swift reply! yes the pressure still came out the morning after the expansion tank was still pressured when I opened it, last question ! do the heads on these need to be skimmed as I read that vw says not to skim them on the forums? thanks again love your work!

Diesel engines in general shouldn't be skimmed (VW / Audi at least). Check with your local machine shop (the experts / past experience) as to what they think.

Lower hose for the most part will be cold to the touch, since the viscous radiator fan is always cooling the radiator. Temperature needle should always stay in the middle 90c / 190F once the engine is warm / thermostat has opened. Temperature (when viewed with a scan tool) can fluctuate quite a bit due to thermostat operation... while the needle in the dash stays steady at around 90c / 190F. If the needle in the dash moves past 90c when the reservoir cap is ON, check the system for pressure once the engine has cooled off over night. On a cold start, first remove the cap and then tighten the cap. Start the engine and allow the engine to warm-up fully. Lower hose should get warm eventually at idle or hold the rpm at 1500 to 2000 until the lower hose is warm. Check the system pressure by squeezing the upper radiator hose. Should be firm but not SOLID SOLID. Shut engine off and allow to cool down for several hours. When the upper hose is cold to the touch, the hose should be easy to squeeze again... if the hose is still solid (cooling system has pressure), then compression gasses are leaking into the cooling system. One or both head gaskets are bad. If you remove the reservoir cap the next morning (after the engine has had time to cool down completely) and you get air pressure coming out of the reservoir... that is a sure sign that there is a head gasket problem. Before condemning a head gasket, install a new reservoir cap, to make sure that the cap is not at fault. The cap should release pressure when the pressure gets too much... usually around 1.4 to 1.6 bar (20 to 23 psi). Normal running pressures can be 15 to 18psi.

Correction / clarification... the cap vents excess pressure to protect the cooling system when pressure is 20psi or more. It is normal for pressure to build & drop when the engine is warming up & cooling down. It is NOT the cap that is lowering the pressure... when coolant gets hot, pressure develops (coolant & the air in the system expand). When coolant & air in the system cool down, pressure drops... this is normal.

Thomas EXOVCDS ok, thanks once again for your reply, hope isn't the head gasket :( I'll replace the cap and do those checks, I don't have yet a milky engine oil. Is there a way to pinpoint if the gases are going to the reservoir? A machine or something, does the liquid that turns from blue to yellow tester works?

Yes, you can get a liquid that changes color when "combustion gasses" mix with the liquid. ScannerDanner has a good video about that: kzfaq.info/get/bejne/oZuGicZ_sKevZok.html

No need to buy a cap yet... check pressures first (by feel with your hand).

You should never open the reservoir bottle when the engine is warm / hot... the pressure in the system can force hot coolant out of the reservoir and you can burn your skin. Cold engine, the fans should not come on, unless you have turned the AC on or the heater on defrost. How high does the temperature needle move? If it goes past the middle (190F /90c), then the thermostat is probably not opening. A bad water pump would not cause fluid to circulate... since you have fluid going back to the reservoir and heat inside the car, the water pump should be ok. The lower hose should get warm to almost the same temperature as the upper hose. So thermostat is probably stuck closed.

hmm...AC is definitely turned of,but I'm not sure for the heater on defrost since I bought the car month ago and I drove it less than 15 times 😂 The longest drive I had it was for around 35 miles without stop and mostly on high rpms...The car is not overheating and what I noticed yesterday is like I sad,fans start to work right away when I turn the car on...when I noticed the problems with cooling sistem,the level of cooling fluid was on less than minimum,I opened the reservoir,fluid came up 1"more than MAX line is...and after 30 sec,the fluid level was on the middle of MIN and MAX...and hoe what's dow was cold,and upper one hot

Drive the car and then park it over night. In the morning, before you start the engine, remove the reservoir cap. You should not have any pressure in the system. If pressure is present... you might have a head gasket issue.

Water pump is on the right front wheel (driver point of view). Follow the leak to the source... I can't see from where I am. If it's dripping from the crank pulley... probably water pump. Don't know what engine you have (can't see from where I am).

Air lock, thermostat, plugged heater core. Check / eliminate one after the other. TDI should not overheat quickly, if yes, I would guess air lock. If the problem wasn't there before, that's another indication of air lock. If you have flow, then it should not overheat for quite a while, in which case thermostat. Heater core could be plugged or the heater control door could be stuck on cold air.

Also forgot to mention I did replace the thermostat as well just wondering if I messed something up. Cooling fans are also not coming on at 96 degrees, but they do come on as soon as it starts to overheat.

The large fan is bad (low speed). Engine should not overheat even if only the small fan is working... you might have 2 issues. Ignition Key ON (engine off), press the AC button inside the car and turn the blower fan on... both radiator fans should spin at low speed. If the large fan is not spinning, disconnect the radiator fan harness plug (of the large fan) and check that one of the 2 red wires has power at the harness plug. If yes, replace the fan, if no, check the wiring.

Awesome thanks Thomas. I'll check it today.

Most likely and air pocket that is still in the engine. Remove the small hose from the top of the coolant reservoir and blow into it. If you can not blow into it, the hose or the nipple that it attaches to at the engine / coolant flange is plugged. Unplug the restriction and check that coolant is flowing OUT of the hose INTO the reservoir when the engine is running. You can also remove the top radiator hose from the radiator and tilt the hose UP, then, fill coolant into the hose until the level in the reservoir is at MAX. Reattach the coolant hose to the radiator. Let me know which method works for you.

@@EXOVCDS ok thanks, I will try it.

@@EXOVCDS replaced one hose and one metal pipe as it had holes and was leaking. Washed out the reservoir, as it had gunk and metal pieces inside of it. Running now on water and Prestone flush. On first day of water and Prestone flush, after getting back home, I popped the hood and noticed that the reservoir is making a sssssshhh noise and so is the hose from reservoir to cooling system manifold, and the hose is shaking. Is that normal for this noise and hose shaking during water and flush?

@@ms-cn8ww A hose that is shaking usually indicates that air or inconsistent flow of liquid is rushing through it. Running only on water can cause bubbles (boiling point of water is 100c). Even if your dash gauge does not show 100c, it could be that parts of the engine are that hot. Flush the cleaner out and fill with 50/50 coolant/water and check for similar noise.

If it ran fine before the timing belt job, it should run the same after... if not, double check what you did. Depending on how / where the break is... it can affect air flow through the MAF... which can / will affect engine performance. You can block off the PCV where it enters the intake tube (ahead of the throttle) to see if it runs better (remove the pcv hose from the intake tube and block the hole in the intake tube somehow for testing).

Either is fine these days... to be honest, I'm not too impressed by "some" of the metal impeller designs / manufacturers. The important part is keeping an eye on the cooling system... flush every 4 years (with new thermostat), making sure that the fans come on when they should etc. , that way plastic or metal pumps will last until the next service schedule.

Thomas EXOVCDS I'm leaning towards a metal impeller, best thing I can do I suppose is not to go for cheap. I've found one made by an oem brand - kolbenschmidt, that's best I've found for metal impeller as vw only do plastic

All hydraulic lifters have plungers... the ones you can not compress are just fully pumped up. Lifters that are soft will collapse easy, but will also pump up once the engine is running. After you install the cams and by the time you get everything back together, the lifters will gave settled and it will be OK to start the engine. If you installed a cam on a fully pumped up lifter, the valve will stay open slightly... that's when you need to wait before starting the engine.

Ooo, Thom, there's a reason we all love you so much! You are number 1! Thanks again so so much!

+Rumen Hristov If I'm wrong... I'm sorry.

I put my trust in you!

Year, make, model, engine? Overheating at idle is usually due to radiator fans not coming on. Make sure that the coolant return hose to the reservoir is not plugged... if it is, air is unable to bleed out of the cooling system, resulting in hot spots due to lack of coolant circulation (water pump can't pump air). Verify thermostat operation... activate the radiator fan(s) manually and check if the engine still overheats with the fan(s) constantly running. Worst case, head gasket is bad.

@@EXOVCDS 2004 Golf GLS 2.0 Fans are running, 2 years ago I replaced the big fan.

Fans are running when? At idle and it still overheats? If you have not changed the thermostat, change the thermostat. A bad thermostat however, will cause the fans to not come on. Post a video so that I can see what is happening.

Recently on short trips it looked to be okay. Yesterday I took a longer trip and the car overheated again. What I noticed was that the coolant connector (902-914) looked to have been wet. And for sure at the molding tab it drips out water. I just went to get it at a local shop only 0.9 miles away, temp was normal getting to the shop, but on my way back it overheated again. So first I will replace this part, see if that brings any relieve. As I live in deep south Texas (Mexican border) car heats up pretty quick. As soon as my car is running and I turn on the AC, both fans are running.

@@EXOVCDS Situation worsened. Can't even drive 5 miles anymore. Last year replaced the water pump as said before, today replaced the thermostat. Also drilled a small hole in the thermostat (1/4') Drove not even 2 miles and temperature went up again, I had AC on so the fans were running while driving. When I pulled over water was boiling, but radiator felt cold. I bypassed the throttle house and still have no flow through that breather hose. Checked the restriction in the line and that was not plugged. So at the moment I can only think of two problems, either the radiator is plugged or the water pump failed on me again. I did replace it, I think with a plastic impeller, but so far have only used it for local drives. Have the car 3 years now and drove in total about 13000 miles, so guess the pump maybe has some 4-5000 miles. Last year when I replaced the water pump (bearing worn) there was rust (sludge) in the system. At the moment I don't have the tools to do the water pump once more (separation/divorce), last year I was already struggling to remove the bracket and put it back in place. But while running the car I think there was some flow back through the bottom hose (was not only spitting air out). Also have the problem that I might have to move soon and need a more reliable car.. afraid I have to leave the VW project.

+Davemotion I'm still at work... will get back to you later tonight.

+Davemotion Could be air, but if you have coolant flow... it should bleed itself out. How old is the water pump? The impeller could be slipping at higher rpm / load.

+Thomas EXOVCDS Thanks for the reply. I'm not sure of the history but the slipping impeller might be a thing... I'll test it again today and see if the flow is slow. I could take the thermostat off and check impeller from there?

+Davemotion Yes... but that's not always conclusive. When cold / cooler, the impeller might feel like it is sitting tight.

+Thomas EXOVCDS Checked water flow again today. A lot of small bubbles almost foaming. Head Gasket?! There is more flow when revs are higher.

Can't diagnose if there are no symptoms / if it's not acting up. Keep an eye on things. If it happens again, check for heat inside the car. If ok, then the water pump is ok. If it only overheats at idle, probably a fan / electrical issue. Green sensors can also go bad. Check the green fuse on top of the battery... for burnt contacts. You'll find the problem easier when it's acting up. Until then, just keep an eye on things.

Thomas EXOVCDS sorry, should have mentioned it only does it at idle... then cools down even when I only drive a couple feet. I.e from the drive thru speaker to the window. So not enough speed to get cold air in, but still goes all the way back to normal temperature (according to the gauge at least)

Watch this and tell me what happens when you do what I do in the video: kzfaq.info/get/bejne/iNWYabV02J6tep8.html

Thermostat that is opening too soon? But usually temperature sensor issue. Make sure it is a green sensor.

@@EXOVCDS Thank you for replaying. I'll try to replace the sensor to another one. Of course green one. But I try to understand, how it's can be thermostat issue? Why the needle stay steady on the middle for the first 15 minutes? What's happening later that the needle float randomaly between the middle and the zero up and down, up and down...? It also could stay sometimes in the middle or at the zero for a good few minutes... Thanks a lot!

Then it's most likely electrical (wiring or sensor). The engine will take longer to warm up when a thermostat sticks open... once at 90c (needle is in the middle) and you start driving at steady speed, the needle can start to go down. If it goes all the way down, then it's not a thermostat issue.

@@EXOVCDS Thank you so much!

pump alone is 2.7hrs according to mitchell labor guide. If other things need to be done, more time is added.

Year, model, engine? I assume 2.0L VW, but which engine code? AEG, AVH, BBW etc?

If you still do not get any heat inside the car... the water pump is probably bad.

@@EXOVCDS It is a 2000 vw golf 2.0 AEG. I now have circulation in the system. There is heat in the car but it takes awhile to get warm and doesn't blow strong. I assume the blend door needs to be replaced.

If you find foam bits in the vents, then yes... probably needs to have the doors repaired. Make sure that the temp control door actually moves fully cold / warm (can be inspected / verified from under the dash / heater box). If you have weak air flow, check your cabin air filter... it could be plugged. If you have more air flow when the heater controls "recirculation" button is ON, that a second sign that the cabin filter is plugged.

I'm not familiar with your engine (not available in North America)... the engine might have more than one thermostat, the water pump could be vacuum or electrically operated (to allow or restrict coolant flow). As for the alternator light, attach a voltmeter to the cigarette lighter socket and measure the voltage when the light is blinking... to check if the voltage is below 12.6V.

My engine is the same as golf/Jetta mk4 series with single overhead cam.its similar to the golf 1.8T and 2.0 models. My car has just one mechanically operated water pump via the timing belt and one single thermostat. At idle my car voltage is 13.52V. will check the voltage when the light starts blinking. Thanks again.

If you keep getting air in the cooling system, your engine may have a cylinder head gasket issue. Coolant "boiling off" from the reservoir (at normal operating temperatures of 90c) can only occur if there is too much pressure in the system. Radiator caps "vent" excessive pressure at around 18psi... during "normal" operation, the radiator cap NEVER needs to vent excessive pressure. You most likely have a bad head gasket.

@@EXOVCDS Can one have a blown head gasket with out noticeable oil leak?

@@davidmosaku Head gaskets can fail a number of ways... oil in to coolant, coolant into oil, coolant into cylinder, oil into cylinder, external coolant leak, external oil leak, compression into cooling system. Each example can be checked for / tested for.

Heat is flowing through vents.

You need to make sure that is it overheating... if it is, don't drive it (will create more damage). Is the fluid level correct?

Overheats when standing still or also when moving / driving? A loose / bad water pump impeller can cause intermittent overheating. A bad head gasket can cause overheating. When the engine is cold, remove the reservoir cap. When you remove it, does it sound like pressure is escaping? Drive the car till warm.... till the upper radiator hose is warm and the hose feels hard from pressure in the system. Shut the engine off and let it cool down completely. If the hose does not get soft, that means combustion pressure was forced into the cooling system. The head gasket will need to be replaced.

@@EXOVCDS they both heat up , but top hose far hotter than lower , when I fill with fluid it doesn't start to over heat til I drive and when I first replaced thermostat , it didn't over heat til I drove about ten miles . Then bam.... After that anything I tried blew the hoses and the coolant distributor failed and broke ..

@@EXOVCDS can't check to see if anything sounds like its escaping now since the hoses are blown but when it was over heating... yea steam... when cold. I dont recall

Replace the hoses and then check the system again. Bad water pump or bad head gasket. Check for lack of heat inside the car and for pressure in the cooling system when the engine is cold (after cooling down from hot).

@@EXOVCDS which will tell me what if there is or isn't pressure after i turn it off? Pressure means head gasket? Don't make sense cause wouldn't that pressure leak out?! Or the opposite?

Patreon account I meant

james Co I have one & PayPal.

Did you find the links?

Donation Done. Your walk through helped me pinpoint my golfs thermostat issue and saved me having to replace every part via covering all the bases lol Tools and parts ordered. Cheers

Didn't mean to force your hand! Much appreciate the donation! Let me know if you need service info... I can send you pdf files. Send me your mailing address and I'll also send you some of my channel stickers. Thanks again!

Yes, bad rad fan. Monitor coolant temperature with a scan tool to verify that it behaves the same as the needle. Replace the fan and see if that helps... let me know what happens.

What color is the coolant temperature sensor?

Temp sensor is green. Figured out what the problem was. Opened up the back cap of the fan motor (mine just pries off and snaps back into place) and saw dirt and corrosion on the pickups that were keeping them from making contact with the central wire coil. A little cleaning and retraining the springs to push the little blocks forward again and she now spins when power is supplied! Case closed id say?

+IaMaPh1991 Thanks for the update!

To replace the fan before checking by putting current directly, I don't think so.

Yes, could be an air pocket... monitor / feel for consistent heat inside the car. Inconsistent heat points towards possible air pocket or water pump impeller issue. Watch the following video about verifying thermostat operation & flow back into the coolant reservoir. kzfaq.info/get/bejne/e9h8hMWE08izdmg.html

@@EXOVCDS So after checking what you said in the video i noticed that im not geting a return of coolant, if i press the upper radiator hose i can clearly see that i get a coolant spray in the expansion tank, so that means that the return hose is clear. Since you said the coolant has 2 ways of going and picks the shortest, I think i might have a closed thermostat problem. Could this be related anyhow to a cloged hester because im not geting any heat inside the car? Thank you for your videos and your answers.

@@svenfirm2142 As mentioned in the video, there will be no flow from the return hose until the thermostat opens. If the thermostat does not open, the engine will overheat. You said the engine does not overheat standing still... so the thermostat is OK. If you don't have any heat inside the car, then you have an air pocket or the water pump is no good. If you hold the engine speed at 3000, do you hear coolant rushing through the heater inside the car? If yes, then you have air in the system.

@@EXOVCDS Thank you for your answers. I changed the thermostat and now I have heat in the car and the lower radiator hose gets warm, but the car still overheats after bleeding the system (8times). I sometimes get a bit of spray from the return hose. I will change the waterpump and the timingbelt. Thank you for all of your help and good luck.

@@svenfirm2142 OK.

Are there any pieces of foam coming out of the vents? Either the temperature blend door is not moving correctly, the foam has come off of the blend door... or your water pump is not pumping (but then you would have overheating issues as well).

@@EXOVCDS The water pump is new, I'm not sure about the blend door; how do I check? The engine does not overheat at all, perfect in the middle.

@@x-man4702 Heater dials or climatronic?

@@EXOVCDS Dials.

Look under the dash from the passenger side... look at the bottom of the heater box assembly while you are moving the cold/hot knob. You should see a lever moving... If the lever is not moving or the lever is not connected, the issue is with the heater control. Here's a video of what to look for: kzfaq.info/get/bejne/bLtpjcecptDImIU.html

Aircooled engines have their own issues... more so than watercooled.

Your water pump is bad.

Did you watch the video... do the checks?

@@EXOVCDS I did watch the video. I have to see if coolant flows back to the reservoir but wouldn’t the fans still kick on?

@@delriomtb9892 the fans are activated by the fan switch in the radiator. If the radiator doesn't get hot then the switch doesn't get hot and it can't turn the fans on. The first check of the fans in the video is just verifying that the fans & fuse are ok. If you have ac and the fans don't come on, then you have a fuse, wiring, fan motor or ac problem. The fact that you have no heat inside the car, tells me that your water pump is no good.