Alright guys, kind of in a dilemma here.

I need to change my engine coolant soon here as it looks pretty gross, just looks like nasty sludge on the dipstick. It's been in the car for quite a while I can tell. Well, I went to an auto shop just out of curiosity to see how much it would cost for someone else to do it and they claim that they put it on a machine and do an "engine flush" for like $90 or so.

I have heard many horror stories about shops doing these so called "engine flushes", however since the coolant is so nasty and old that's in there currently, would it still be a bad idea? Car has 73k almost 74k miles on it and I'll be honest, it looks like it was never changed before. The other option is to just go through the average coolant changing process, basically drain the old crap out and just pour some new stuff in and be done with it, no flush or anything like that. What would you do?

Opinions, comments, suggestions?

Thanks a bunch in advance guys.

 

The horror stories are from engine flushes (oil), not Coolant flushes. Don't let them do and engine flush! A coolant flush is ok.
There is a few threads on here about people's favorite way to do it themselves.

 

Here ya go. My write up. Looks like allot, but its easy. Read through it, then go do it. I would do the degreaser part if I were you.


Best/easiest way to flush and get every drop of old coolant out.

****My power steering fluid leaked into my block, so it was bad, but this flush process works for normal maintenance flushes too. You might just want to skip the degreaser stages.****
-Cold engine.
-Remove radiator fill cap.
-Remove the t-stat from the housing. ((Buy a new t-stat housing gasket, they're like $3.00)) Leave the housing attached to the rubber radiator hose, just remove the 2 housing bolts and pull it away from the water pump to get to the t-stat. (2-3 minute job). ***The t-stat itself can be removed from the so-called one piece t-stats just like we can remove the t-stat from the newer two-piece t-stats. And the housings will bolt right back to the water pump.***
-Put t-stat housing back on. (1 minute) Just put one bolt in, no need to put them both in, there’s no pressure in the system during the flush.
-Take the entire radiator drain valve (petcock) "off" and let it drain, don't just open the valve itself. It'll drain faster with it off and that’s what you want. ((Buy a new petcock valve before starting this flush process, sometimes they break when you remove them all the way just because they're cheap plastic and they get briddle over time, they're like $2.00))
-Take a hose and stick it in the radiator fill cap, running medium to high.
-Start the engine when the radiator looks like its full again.
-Turn heat on full blast
-Let it run for about 15-20 minutes or until the water is running out the drain CLEAR.
-((If you want to, you can wait till it runs clear, "close" the drain valve, add some degreaser (I use ½ gallon of Formula 88 to clean mine) and let it run for 15 minutes, then let it sit for 15 minutes, then run it for 5 minutes, then drain it all again. Then open the drain and put the hose in for about 5 more minutes and run it all out till its CLEAR. The degreaser will help break up the crap thats stuck DEEP in the BLOCK that sits and swirls and doesn't like to come out.)) ***NO…degreaser will not hurt anything. Just make sure its ok for aluminum.***
-When it runs clear your entire system is clean.
-Remove the overflow reservoir from the car and clean it out real good. (I had to use gasoline to clean mine out because the sludge and grime was so thick inside. The gas broke it all down and then it flushed right out. I filled it about 1/3 up with gasoline and shook the hell out of it real vigorously, the black stuff kept coming out. I did that like 4 separate times with gasoline till no more chunks of black crap came out. Make sure the lines that go to the reservoir are also cleaned out. Or just buy a new piece of 3/8” heater hose and replace that line, 3 feet will do, then cut to fit. My sludge came from my power steering fluid leaking into my coolant system.)
-Put the t-stat back in.
-Put the overflow reservoir back in.
-Put the drain valve back in. Use the new one, what the hell.
-Put half a jug of Dexcool in the radiator. (Or if you live in very cold places, 1 to 1 ½ jugs of Dexcool)
-Fill the rest with water.
***You do not need to use distilled water, clean hose water is just fine, just make sure your city water is clean and not total crap quality.

**Bleeding the system of air:
Take the radiator cap off when its COLD, top it off, start it up and let it idle, and let it warm up till the t-stat opens. I rapidly squeeze the upper and lower radiator hose like 20 times each while its warming up to help move any air bubbles through the system and by the t-stat on the engine side. When the t-stat opens you’ll see the level drop as you squeeze the hoses, its sucking the coolant through the system. You will also see the coolant start to flow in the radiator fill neck, once it starts to flow the level should drop down a lot, IMMEDIATELY top it off with coolant/water. Then the flow will stop when the t-stat closes. Wait one more time for the t-stat to open again and start to flow, if it drops down again top it off again. Do it a 3rd time if you want to make sure. When the level does NOT drop down when the t-stat opens and coolant is flowing....you're system is free of air bubbles. I always squeeze the upper hose during the whole process to keep any air bubbles moving through. Always works like a charm. Just keep checking your temp gauge until the t-stat opens for the first time to make sure it’s not sitting there overheating from a trapped bubble. May take 10-15 minutes for the t-stat to open the first time.
If you do start to get hot while sitting there and the t-stat will not open…..you have an air bubble on the engine side of the t-stat. Shut the engine off and rapidly squeeze the upper and lower radiator hoses again. Then start the engine again and see if the t-stat will open. Sometimes you just have to work those hoses to move the air through. Even after it seems topped off after a couple cycles…check it the next time you have a cold engine…top off if needed.


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Ahhh, I gotcha. But, the person who I talked to at the shop made it sound like they weren't only going to do a coolant flush, but an actual engine flush which is something I don't want any part of, maybe I misheard her though. Thanks for your input man.


LS6427, that's a very helpful write-up, thanks a lot for posting that up. I'm on the fence about doing it myself however because I feel like the machine at the shop I plan to take it to will do it much faster and do a much better job than me myself, I'm a complete noob at this stuff. I mean the coolant that's in the car is very nasty, looks almost like poop and has little particles in it, I can't believe my car hasn't been overheating. As much as I hate to do it, I just feel like it really needs to be thoroughly flushed out by a professional.

 

My flush with degreaser is better than they will do it with that machine. That crud gets in the block and swirls around in certain areas and it takes allot of time to get it all out. Just flushing with a machine won't really clean it....unless they use degreaser.

But thats cool. Just be there when they do it and make sure you see pure fresh water coming out of the drain, or wherever they are expelling the dirty coolant from. Some shops are good and they'll do it right, some will just swap the bad for new coolant and it will still have **** everywhere in the system. Its hard to clean out the heater core too.

Also, make sure you remove the over-flow tank and have it rinsed inside with gasoline or a strong degreaser.....you'll be amazed at what comes out of those things after allot of years.......fill it about 1/3 with gas or degreaser, shake the hell out of it and dump it like 4 different times. Buy a new 3/8" heater line for it too. You'll have to buy one clamp for the metal tube on the overflow tank.

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Yup, I hear you. Your degreaser method seems extremely effective. Seems like it would get rid of all the old coolant and other little particles.

The main problem is that, like I said, I really am quite the amateur when it comes down to actual hands on work with stuff like this. I can't afford to trial and error on something involving the coolant system because that can end up doing serious damage if it's not functioning like it it should. Can't afford to take that gamble since it's my daily driver. So, I'd rather just leave this type of thing to someone who knows what they're doing. Even if it's not done 100% perfect, it has got to be better than the diarrhea that's flowing around in there at the moment.

 

Ok.....maybe they'll allow you to run degreaser through it, mixed with the water they run through it to clean it. Then let it sit for 15 minutes. And don't let them tell you it'll hurt things....it can't hurt anything, as long as you use a degreaser that does not harm metals. Formula 88 is awesome.

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Yeah the overflow will get nasty looking, but if you look into the actual radiator it will not be that way.

 

So your recommending to dilute the degreaser? How much 50-50 with the water? I think I'm gonna use the degreasing process seems like it would be pretty effective.

 

Not sure what the ratio is....but I pour 1/2 gallon into the system and let it circulate. Its a pretty strong ratio that way.

It will also suds up allot when draining the degreaser out....takes a long time to get all the degreaser out. When you stop seeing the suds and bubbles, its all gone.

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