Pull Engine Block Drains When Changing Coolant

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Pull Engine Block Drains When Changing Coolant

Рет қаралды 17,827

Жыл бұрын

It is important to remove the engine block drain plugs when changing coolant during routine maintenance. I learned this the hard way due to cooling problems on my 428 Mustang. Over many years, scale and other deposits can build up at the bottom of the engine block and restrict coolant flow in the water jacket around the bottom of the cylinders. This can lead to uneven cooling and overheating. While I encountered this on my 428, it applies to most engines. My 3rd Gen Camaro 305 has the same type drains in roughly the same location and even though I have a fresh clean block, I will remove these plugs at every coolant change for prevention. The right hand side on mine actually has a knock sensor threaded into the drain hole.
IMPORTANT NOTE: "Block drain plugs" refers to the pipe plugs or other fittings provided in the engine for purposes of draining the water jacket. These are NOT the core plugs, commonly referred to as "freeze plugs" that are sheet metal type plugs pressed into the openings in the casting. Those plugs should not be removed. If you are not sure, check the service information for your particular engine to locate the correct drains. Each engine design is different and may have different type plugs, or methods to drain the block.
DISCLAIMER: In my videos, I provide demonstrations, suggestions, and opinions on techniques, methods, and materials for various projects. While I try to be sure that what I share is accurate, there are no guarantees, expressed or implied, that my information is correct and will work for you. If you wish to use any of this information, you must check and verify that it is appropriate for your use - use it at your risk. Do-it-yourself projects are variable and there are risks in conducting them.

Пікірлер: 42

@prycewilkins 2 ай бұрын

For only a 9 1/2 minute video this is a wealth of knowledge and I appreciate it. I have a 79 Chevy K10 350 4 speed and have never even considered the block drains until now. Thanks again

@josepha8759 8 ай бұрын

I used the flushing product made by Evaporust in a 1990 chevy smallblock. Before doing that, I removed the block drains and poked until old coolant was coming out. I used the product in warm weather so there was no danger of freezing, and left it in a few weeks, running the engine for 10 to 20 minutes every day. When I drained it, it was coal black. I had to flush with cool water about 20 times to get it clear. Each time I drained first from the block drains. Eventually I got all the crud cleaned out. No overheating now.

@bitsofwisdom460 8 ай бұрын

That sounds like great success, I am glad that it worked for you. I had heard about the Evaporust product and checked it out, but the company doesn't publish the active ingredients even in the SDS. It is labelled proprietary. I am always a little cautious when I don't understand the product, so I chose not to use it. But, your success is a great testament to the effectiveness. It is also good to see that once the crud is flushed out from the bottom of the water jacket, the engine is much happier.

@RobertTrask-uu8dd Жыл бұрын

Thank you SO much for taking the time to make this. Watching it changed how I approach maintaining my 2002 Tundra (which I plan to keep for life). You're a good human.

@bitsofwisdom460 Жыл бұрын

You're welcome. Glad that it helps.

@frankevans287 9 ай бұрын

Thankyou, sir, this great advice, most people don't even know to consider them. When I was in high school we were taught how to rad flush as you described, no mention of the block plugs, this is something I just learned of a few months back

@bitsofwisdom460 8 ай бұрын

You're welcome. I really didn't think much about it until I had a problem. I like to share the lessons learned over time so perhaps others can head off a problem.

@cart-wheels Жыл бұрын

Wow! I'm glad you showed a picture. I was thinking it was the freeze plugs. Great advice, as always, thank you! Great advice on the radiator. My radiator was replaced years ago and I think the replacement part isn't as good. Thanks!

@bitsofwisdom460 Жыл бұрын

Yes, the pipe plugs rather than the pressed in core or freeze plugs. They aren't real large, 1/8" or 1/4" pipe thread in my engines.

@HalJalikakik 10 ай бұрын

Thanks for posting this! The 383 in my ‘74 Challenger is overheating and I replaced the entire cooling system with no improvement. I’m going to take your advice and get underneath.

@bitsofwisdom460 10 ай бұрын

I hope that it helps!

@LJC5865 Жыл бұрын

Drain all coolant then remove block drains and insert a curved rubber tube to reach the bottom of the block and drain both sides. Rinse the block through block plug holes with high pressure water hose. Leave open then flush system with water hose at heater hose both directions. Drain again to the block bottom then replace 1 block plug and fill block at the other block plug location with superflush and leave it there as long as possible to soak. Then use high pressure water hose to breakbup and flush the block til it's clear. Then drain completely using the tube again at the bottom of the block each side. Fill system with flush and distilled water and drive 200 miles. Drain completely including tube at the bottom of block both sides. Then fill with coolant and drive another 15,000 miles or so until time to repeat the process. I think using alot of high pressure hose water in the system and block is worth it because draining the system and block to the bottom with tubes isn't leaving enough hose water to cause any harm. If you're good at it then tilt the car like a rocket (LOL) and drain the block completely with a longer hose.

@bitsofwisdom460 Жыл бұрын

You give some food for thought. I didn't try much from the bottom. Those drain holes are very small pipe plugs on my engine and you can't get much of a hose through them, but perhaps it would be worth a second look. It may be possible to help loosen deposits up from the bottom. I did high pressure flush (100 PSI) from the intake manifold heater connection behind the thermostat and then back from the lower water pump hose to the upper hose with the thermostat out. The flush chemical seems to need heat and flow / agitation to help the process. I don't think it does much when cold. Most chemical reactions increase with higher temperature, so it makes sense. The flush did seem to loosen and move deposits with each treatment so that they would flow out. I don't think you would need to tilt the car to drain trapped water at the bottom once the deposits are cleared, because I think that the plugs are at the bottom of the water jacket so that only a few ounces will remain. On my marine engines, those plugs are used for winterizing and they drain all but a couple of ounces of water.

@DIXIEMAFIA251 Жыл бұрын

Thank you for your wisdom SIR! (1996 Chevy Silverado k1500 5.7 Vortec,Dogleg 4wd) sittin on “33’s! You officially have your newest subscriber! I encourage you to make more videos please!Youare very informative,And detailed with a wealth of knowledge!With love from Gulf Shores,Alabama!

@curtisway5957 Жыл бұрын

I always use a six-point socket on block drain plugs, especially if it's a new (used) vehicle. Once I have them out the first time I use teflon tape and have no further issues. Just be careful not to over tighten as that teflon tape is is very slick.

@bitsofwisdom460 Жыл бұрын

Yes, the six point is a must for these hex plugs. I have had some with square drives and some with hex socket plugs, those can be even more tricky to get out.

@NICU2 10 ай бұрын

this was the exact video i was looking for. I put a performance aluminium radiator on my hemi and it was a little thicker so my upper hose rubbed on my pulley and blew. id like to do a flush, so i was looking for info on draining the block but couldnt realy find one, thanks for this great video, ive never drained a block either and now i will for ever

@bitsofwisdom460 10 ай бұрын

You're welcome. Glad I could help. I know that different blocks have different drain plugs and drain locations, but it is worth tracking them down.

@steveo170 Жыл бұрын

I read that using tap water with all the minerals it contains is discouraged. I decided to use the pre-diluted coolant in my rebuilt 350 L83. Not sure if there’s anything here but giving it a shot. Thanks for sharing your knowledge.

@bitsofwisdom460 Жыл бұрын

Yes, you are correct. Water quality matters and mineral content can add to the build up and scale. One of the challenges is that it you do a flush, and don't drain the block, you still have the water from the garden hose in the bottom of the block. I was on well water for some of the time. I would try to flush with softened water to help that - tricky to get a hose from an inside faucet since normally outside faucets aren't plumbed for soft water. Now I drain the block to be sure it is empty and use distilled water for mixing. Pre-diluted is certainly good, too.

@sypher0101 Жыл бұрын

@@bitsofwisdom460 What if you pulled the block drain plug, removed the radiator hoses, removed the thermostat and shot pressurised water through the system, draining out of both the other radiator hose and block at the same time until clear water, then run a cycle of Radiator flush before draining again and filling with fresh Coolant? Would water from tap be ok then as you'll be flushing it out anyway?

@bitsofwisdom460 Жыл бұрын

@@sypher0101 Yes, you can run tap water for flushing, if you remove the drain plugs and open the radiator drain when you are finished. That should drain all except possibly a couple of ounces of the tap water. Then plug / close the drains and fill with fresh coolant and distilled / deionized water.

@user-ds9zd8eq6u 2 ай бұрын

I knew about the drain plugs,but never used them or their exact location, I'm going to do it today!! Ty!!

@Malachi4DaWin Жыл бұрын

Hi thanks for sharing your knowledge, Something l must do on my 85 iroc she runs ok in winter but doesn't like the summer heat,l have flushed the radiator and she's had a new water pump but it made little difference

@bitsofwisdom460 Жыл бұрын

You're welcome. Cooling issues can be difficult in some cases. If the water pump isn't leaking, it usually won't make much difference. There are cases where the impeller can corrode and not be efficient, but I don't think it is common. On the 85 IROC, there are a few things to look at: 1. First, if you have Tuned Port, the factory electric fan is set for about 220 degrees F. So, it will be normal to see 220 or so on the dash gauge in summer in traffic. If you're running higher than that make sure the electric fan is triggering at the right temperature. There is a thermal switch and relay to control that. Not sure if the carb models have the same system. 2. The fan motor could be defective. I had to replace mine because the bearings were howling, but the motor could also be weak and not making the correct speed. See if it seems that it is running normally. 3. Be sure that the air dam under and behind the front bumper is in place and intact. It is under the radiator. That air dam helps push air up into the radiator. 4. Be sure your thermostat is in good condition. You want to stay with a factory rating--195F as I recall. But sometimes they don't open all the way. It is a little difficult to reach if you have TPI. 5. Consider running the Prestone Heavy Duty Radiator Cleaner as I mention in the video. It will help clean scale out of the radiator tubes and block. Follow instructions on the package. I think the IROC needs two bottles and you run straight water with it, so you need to be sure you are out of freezing temperatures to do that.

@budsodalsky Жыл бұрын

WOW - never knew there was block plugs OR that binford 2000 gun! What about my 1955 chevy 6 cylinder, would it have a block drain? what about my 3.1 camaro 6?

@bitsofwisdom460 Жыл бұрын

I think if you get underneath that you will probably find them in both engines. I have seen square heads, hex heads and socket heads on the plugs. Incidentally, these are the drains the marine engines use for winterization.

@budsodalsky Жыл бұрын

@@bitsofwisdom460 You see, I always knew they were on marine engines - my gm "iron duke" 4 cylinder boats- i always opened that to winterize them when I lived in Hoosier IN - never paid attention on my classic cars - Your videos are very informative - keep em coming Dan! Fellow Purdue Alum! (Purdue is #1 in the country in Basketball right now Dan! Hail Purdue!)

@patrickwilliams4788 Жыл бұрын

Can you tell us the name of the strong chemicals you used to eat up the crud in the lower part of your engine block?

@bitsofwisdom460 Жыл бұрын

Well, I'll provide this for information and not with any recommendation. I don't know why they disappeared from the market somewhere around the early 1990's, and there are safety precautions needed with the concentrated acids. I found a reference through internet search -- Google books, Popular Science June 1973 that had an article about different radiator cleaners that were being sold in the retail market and some tips how to use them. The active ingredient in a couple of the major brands (Dupont and Prestone) was reported to be oxalic acid powder, frequently sold as wood bleach, some form of a detergent for grease or oil, and a neutralizer called sodium carbonate (washing soda)--not sodium bicarbonate / baking soda.

@patrickwilliams4788 Жыл бұрын

Thanks for Answering my question. I have another if you don’t mind. Is it a three step process? Oxalic acid then rinse? Then detergent for grease and oil and rinse again? And finally rinse with the neutralizer (sodium carbonate)? I wouldn’t want to mix the acid and detergent together would I? Your videos are very well done thanks again Pat W.

@bitsofwisdom460 Жыл бұрын

@@patrickwilliams4788 It is a two step process. Based on the Popular Science article, it was reported that there was a detergent in the mix with the acid. When I did mine, I didn't use any detergent. I had already run multiple flushes with a current generation cleaner and decided that de-greasing likely wasn't necessary after all that cleaning. I was also uncertain what concentration to use. The process was to use the acid portion and follow it with the neutralizer to stop the action of the acid. I encourage you to look up the Popular Science write up because it gives a very nice background and some good details. Just search the string "Google books Popular Science June 1973" and look up page 122.

@mikebruegger8654 Жыл бұрын

Nice to know! Do small block Chevrolet engines have the same? I know they have casting holes sometimes called freeze plugs, but they are more permanent and a pain to remove. Be nice if I could flush out the bottom of the IROC.

@bitsofwisdom460 Жыл бұрын

Yes, the small block has them. My 305 has one pipe plug on each side of the block in the same area. I think the right hand drain has the knock sensor screwed in instead of a pipe plug. You don't want to try to remove the casting core plug / freeze plugs. Those aren't meant to be removed unless the engine is out for something major. I know that on occasion one will leak and need repair, but otherwise leave those alone. And yes, while those core plugs are often called freeze plugs, that isn't their purpose. My original block apparently froze and cracked and those plugs looked just fine.

@mikebruegger8654 Жыл бұрын

Yes, I did have to replace one by my starter that was leaking. It made for some colorful language...

@tireroastersgarage 3 ай бұрын

Thank you friend!

@bitsofwisdom460 3 ай бұрын

You're welcome!

@stevecarlson6462 Жыл бұрын

I will try to loosen the block drain bolts on my '98 chevy 5.0. If they don't drain, I will just twist them back in. Why open a can of worms on a 200,000 mile engine? Besides, I already flushed it with Thermocure and it's pissin' clear distilled water when it drains. It would be great to drain the block completely though.

@bitsofwisdom460 Жыл бұрын

If you're not having an issue, it may be fine either way. Checking to see if it drains is just another clue to the state of your cooling system.

@stevecarlson6462 Жыл бұрын

@@bitsofwisdom460 It did drain. Thanks for your opinion. Everything worked out well!