I really like how he also tested it at the exhaust pipe showing us how it works when a leak is detected.

My leak detector instructions mentioned nothing about taking coolant out of the radiator to test. Tried it so many times and the coolant just flushed into the tester and ruined the test. Thanks so much for including that info!

Thank you, I like how you explained everything in doing this test. This was very helpful and informative. I'm glad that it was only your radiator that was the culprit.

Great video! Concise and clear instructions, and you made the liquid turn yellow as proof. Thanks for this!

I've watched several video's on this subject. this is the best one. great job. He gave me the confidence to do it myself!!

Thanks for sharing your experience with this tool. Being as old as I am, I can honestly say that I hadn't seen it but once before on another KZfaq channel. But the guy never explained how it works. You did a great job of explaining and truly show it in action. 👍👍👍

Great video no body else explained how much antifreeze to take out before the test or that u need to wait until operating temp. Thanks so much

Great video, but you can also test it in the coolant reservoir without having to worry about coolant jumping out of the radiator

VERY well explained !! Many details that other KZfaqrs don't give... Thank You very much!!!

Nicely Done! I love the regular guy style and delivery you have. Think Ill just test mine for fun!

Excellent video, good, clear, complete instructions and you created understanding. Thank you! EDIT: I ran the test today, and all is GOOD! Whew! I did not want to replace a head gasket. NOTE: if all is tight and right, once you pull a vacuum on the radiator, it's very difficult to get any more bubbles. Revving the engine seems to give a little more, but the test took a long time to run since I just wasn't getting bubbles. I wanted to get as good a test as possible.

This was a really useful video, including a cross check to prove that the detector fluid actually works at the tailpipe.

Nice and detailed video liked the end part too with the exhaust to show how it would work if exhaust combustion

Awesome video, you explained everything in detail, plus some. Thanks

Broski this video is so dope! Well executed and explained 👍🏼thank u so much..much appreciated

Great video man, clear and concise. No BS.

Thank You! My take-aways; lower coolant first, engine hot, 1 minute test, then check at exhaust!

Great videomate clear concise instructions!! Well done!!

Totally awesome video. Learned something new. Thanks dude!!

Thank you for clearly mentioning the engine must be warm. Others don't do that.

Thanks, very helpful video. You explain things well.

Great method to double check the exhaust

Great job, keep new vids coming

Excellent explanation. Thank you.

Very nice tutorial, thank you & keep motorin'.

Thx @ Nus and Bolts Auto, I just got my tester in today from amazon and tested immediately with promising results. My problem is i just bought a 2008 sequoia from craigs list w/ 233000 miles, I test drove it, checked cold start check steering fluid and inspected the bottom for any leaks from engine and trans, all was well until. I noticed i was loosing coolant, so i bought more and it would slowly lower in the reservoir, I did notice a leak behind the radiator where all the red coolant collects and dries out, also think the water pump may be leaking from weep hole, really that wasn't my biggest concern. I was really concerned the original owner drove with low coolant and overheated the engine and thats why they sold it. so it was a relief to run the same test and come up with good results, now I feel better about replacing the radiator and water pump with no major concerns about a head gasket. I used a suction pump to take fluid out from radiator and let the truck run idle for about 10min the radiator felt hot and temp gauge needle was in middle so i assume the thermostat is open and pumped the little ball for another 7min with solid blue color. FYI to craigslist buyers, check behind the radiator with your phone camera, when i saw this truck the front of the radiator was clean with no evidence of a leak, also got my spark plugs changed and no evidence of oil on the plugs so I'm happy.

Great video dude! Thank you.

Clear instruction thank you !!!

Dang i should have picked up this tester. I purchased a different brand, and it didn't come with the hand pump--it came with a vacuum line hose. What a pain! I'm returning it I think. Excellent video and I really like how you did the exhaust test at the end as proof of test.

Great video, memory refresher! Thanks! Blue results (with a leak) could also mean a seeping intake gasket, and rule out a bad head gasket.

Great vid!

This! I wish all tutorials on KZfaq were this concise and direct!!! And he didn't feel the need to point the camera in his face and say "what's up guys!" With thug rap in the background!

Just tried it thankfully my head is fine so thanks a lot

Thanks for posting!!

Fantastic video

Thanks for the video, and God bless you!

Great video. Thank you. Do you know if a combustion leak test is the same as what mechanics call a "block" test?

Thanks for your Video

idk how this video doesnt have many likes!! its soo interesting 👍😀

Great video!

Clear video. Thanks.

Thanks man you’re awesome!

Thx Bud. Looks like my engines good.

I'm impressed 👏

Thanks for your video I have the same problem going to be on my 3 radiator. Did the 3rd radiator worked?

Awesome, thanks!

Could you just remove the thermostat to speed up the process and eliminate the coolant expansion issue ?

So i made my test wrong! Now i know it. Thank you so much! (It actually sucked coolant on both cars i have tried. The blue liquid stayed on top of the yellow-orange coolant and never changed color. I would bet it's still fine, but i'll do the test differently tomorrow just to be sure)

very good video, even more helpful than scottys video lol thanks alot

In my case it’s a very subtle leak. Customers says at times he can drive a hundred miles and not loose coolant then all of the sudden it loose enough for the car to overheat. When I did the test the color remain blue but you can see yellow tint in on top of the foaming as it bubbles when you press the bulb. The test fluid remain blue but with a different hue of blue from original color. I pressure test it but it holds pressure for a long time. It looses one PSI in about 20 minutes. I don’t see any visible leak even when I pressure test so it has to be the cylinder head

I had a couple of bad head gasket symptoms. Pressure in the radiator overnight when cool. Reservoir getting overfilled. So I got together all the parts, went to get coolant, and the radiator burst. So I got a new radiator, and the reservoir is actually dropping a tiny bit after it cools now. So i get this tester and the color doesn't change, so great then. But I held it up to my exhaust, and the color still didn't change. So that was a waste. What could I be doing wrong?

I tried this today(i have coolant expansion tank), and my coolant was only 1-2" down, not 2-3" like it was recomemended so that it doesnt mix with coolant and contaminate test fluid when you start squeezing, and after only couple of squeezes, all my blue stuff when into the coolant. Is that because it was not enough empty space between, so it sucked my test fluid inside the coolant tank, or my block tester is not good? Also, now this tester fluid is inside my coolant. Is that bad for coolant system? I mean, its small amount of fluid, but i dont know if it have some checmical that's bad to be inside coolant system?

I have either an exhaust leak or a valve tick....can i use this where i suspect the exhaust manifold is leaking to find if i do have a leak or not? I would imagine this would work

Need to get this tester because i'm losing coolant but have ZERO signs of a leak. the coolant gets stuck in the reservoid and not gets sucked back into the engine. but it will overheat on me JUST ONCE this year.

#1) The block tester I borrowed from O'Reilly (from EverTough) warns in the enclosed a paper from the manufacturer to NOT USE ON DIESELS. (Luckily I have a gas engine. #2) After removing the antifreeze from the top of the radiator ( giving me 2" of air space I sucked the tester 6-7 times with the engine ideling at about 700 rpm. Like you said you only have ab

I tried testing my civic, but it doesn't suck air into the tester just the first time. Any idea why?

So if Thermostat is faulty and stuck closed would the test not work , would only be hot water in expansion or radiator?????

What if it tests ok but you still get a sweet smell from exhaust on start up?

So I just literally did this on my girls 7th gen civic and the fluid turned yellow then it turned blue again. What's up with that? Does the fluid turn back blue one it stops detecting exhaust gas?

if possible, would you recommend using all water in the radiator?

What if you don't have a radiator with a cap? Can I do it on the reservoir

I had a problem and wonder if anyone can explain l. I drive an infiniti g35x, 2006. I siphoned around 3 inches below the radiator cap and tried the test and it sucked up radiator fluid immedietly. It rose up immedietly after starting engine. So i disconnected that little hose to see if that would help. I started the test and roughly 60-80 seconds of pumping later it started sucking up radiator fluid. Im scared that 60-80 seconds wasnt enough time to get an accurate read and i dont know why the fluid rises unless its just the heat

Excellent! Comment for quality.

What do I do with the coolant that was sucked out am I able to put it back ?

I bought one of these, but when i press the bulb it stays flat. I can't pump it. Any suggestions?

What about with a Prius. I feel like it has such a strong pressurization at the reservoir that the bulb won’t allow you to get any exhaust up into it lol

So if it's turn yellow from exhaust -thats normal? I had blue on my coolant reservoir, but yellow on exhaust pipe!?

In the harbor freight manual it says yellow for gas engines and green for diesel. Mine turned green on a gas engine. What the heck does that mean?

What would happen if the test fluid gets mixed with the antifreeze?

I used a combustion leak detector that turned yellow. My radiator is leaking from the actual radiator. Can this create a false positive?

You where differently on the right one thing is that idle at temp will show a false reading take for a drive under a load and retest it has happened to me all signs point to head gasket but at temp idle no gas present after the test drive user load gas was present

My leak detector didn't say whether to do the test cold or hot. I wanted to do it hot but when coolant flows through my radiator it splashes up into the tester and ruins the test. I thought at first it was splashing because of bubbles but I think its because my radiator has a top flow outlet hose that is mounted very high, slightly higher than the cap. so anyway, I did the test on a warm engine and it was negative, and I was also able to get about 5 pumps after the thermostat opened and it was still blue so hopefully it was accurate.

Will this work on a very early/minor leak????

Can I use this in overflow tank?

Great Video! I'm thinking if you pulled your thermostat out you can test right away, correct?

What if the leak is going out the exhaust? What's the test for that?

If it does turn yellow, how do u know if its the gasket, block or cracked head? My car is spitting coolant out the reservoir and boiling. Plus the oil filler cap has a milkshake looking substance on the bottom.

I thought you had to do this test on a hot system to ensure exhaust gases are present? Exhaust gases can dissipate during a cold soak.

Great explanation, do you have to bleed the system after doing the test?

Bro need help.. i did you test and same thing happened.. no yellow on radiator test . But yellow on exhaust pipe, does it mean i have bqd head gasket?

Does this also with testing from the expansion tank? My cars radiator doesn't have a cap.

Thanks for the video. One question. How is the used test fluid disposed of correctly? Many thanks.

So how’s everything now? Did the replacement radiator work as you suggested, or was there more?

I gotta say, very, very good video. I was hoping to figure out what to do if the suction bulb has gone missing but you still have the box and everything! If you read this and have an idea, please reply. Thanks.

Did you tell them once it's at operating temp to turn the heater on full to give them the 60 seconds? If you don't open it you will NOT have 60 seconds.

i only get a few squeezes of the bulb and it pretty much quits expanding. i assume that is because i don't have a leak or at least not much of one. i waited with the bulb colapsed for over a minute and no change, no air flow through the tester.

What fluid is actually used?

NUTS AND BOLTS AUTO {""" " The coolant combustion tester/detector will only test the coolants fluids for a bad head gasket? The Coolant combustion tester/detector doesn't test if the water pump is work correctly or if the radiator and engine has rust and other chemicals in the coolant?

I am honest to god terrified yo do this test because I really do not want to get rid of my truck

What if my fluid stayed blue at first but several days to a week later that same fluid I left in a cup ended up with a layer of yellow/green on top?

Just so you know, the Maddox kit at Harbor Freight DOES NOT come with the test fluid. Oddly it is sold separately.

The Exhaust tail pipe test is not accurate because gas is a coming out of it tried it on my four wheeler lawnmower and it turned color . In the test and they do not have coolant

So how come every place doesn't show the list of things that make up the fluid.... Coolant they show the back lable, oil... But block tester you have to buy it to see the back... What is it made of stuff easier to get without spending as much.... You don't even really need the kit to test either just a way to get coolant from the system into a container with the block tester fluid....

Ford Ranger 3.0 huh? Been there done that! 3 Radiators, 2 Heater Cores and Long block from Ford. lol Heater core gave, about 45k RR from NAPA. Radiator gave shortly after RR. Rad from NAPA Truck started steamin out of tail pipe. On day in the AM I catch a large chooch of white cloud. Cracked head - Vulcan 3.0 Alum/Iron, Ford did the long block, new Rad as it cracked driving it to work. After the long block / rad job warranty ran out heater core goes, I just bypassed it from then, rad goes out slow leak that got more and more noticeable. I got a new Rad from 1800RAD with lifetime warranty and installed during my lunch break at work/shop in the lot. It's set off by Co

My problem was I could only squeeze the bulb a couple times because the vacuum of the engine

Tried this and it started to suck up coolant into the testee. i guess i am supposed to drain the coolant a bit?

Thanks. So. It you’ve a thermostat stuck closed. The test cannot be done yes. Tanks

Do you have to disable the thermostat when doing this test?

Block Tester BT-500 kit: amzn.to/38c0Pji

i’m trying to test this on my hyundai elantra, coolant just keeps getting sucked into the tube, do i have to completely empty the coolant reservoir? it just keeps going up no matter what...