A few months ago I got my coolant flushed at a shop around here. Apparently they put green coolant into the system but they didn't get 100% of the dexcool out of the system Are shops with the coolant flushing system able to get every last drop out coolant out? Its annoying that it seems like this shop did a half *** job.

I went to check my coolant level today and there was a small piece of sludge on the stick. It also looks like the green is mixing with the dexcool because under the radiator cap you can see green and brown.

What should I do in this situation? Will anything happen if I leave this the way it is? Nothing has happened with the car but I would really like to get this completely flushed by a different shop and put in fresh coolant. Is it recommended to put green in or put the dexcool. Is there going to be any harm to my car with the green coolant and dexcool mixed?

Also, I noticed recently that upon startup and backing out of my garage I have a squealing/squeak noise. It usually goes away once the car warms up. Its never done this before. Not sure if the two are related.

 

I had the same thing done a few years ago and they used green coolant. I have sludge on the dipstick but the coolant in the radiator looks fine. I was advised to just keep an eye on it and that's it. I actually intentionally switched to green after reading how dexcool interacts poorly with aluminum. There's really no way to get *every* drop out, because some will hide places where the pressure just isn't going to clean it out. Personally if the sludge gets worse I'm going to have it flushed again and green added again. After a few times of doing this I imagine any dexcool residue should be gone and the coolant should be clean. I know this sounds expensive but I drive the car infrequently enough where I'll probably only do it about once a year. I think switching back to Dexcool at this point would be counter-productive and just cause even more sludge.

 

Well, you know the old saying......if you want it done right you have to do it yourself. Unless yo9u have a leak somwhere making the coolant dirty.

I've found only one way to get every single drop of old coolant/dirt out of the entire cooling system. Taking the t-stat out, putting the t-stat housing back on, pulling the drain on the radiator and letting it run for 15-20 minutes with a hose running in the radiator. Flushing with the t-stat in is just corny and won't really work that well.

When you say "sludge"...do you mean dark colored gummy looking ****? If its black its got nothing to with old coolant. Do you have the factory power steering fluid cooler in the upper radiator hose? Are you auto tranny with the tranny fluid lines running into the radiator?
You could have a leak in one of them, putting fluid into the coolant. The worst scenario is a cracked block and its oil getting into the coolant...which I doubt is the problem.


There's absolutely nothing wrong with Dexcool. I don;t know why some people have problems with it. If your coolant system is sealed and in good condition, Dexcool will stay clean and last for 10 years.

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Yeah, dark color brown gummy looking ****. Its definitely not black. I would find it hard to believe if it was a cracked block with only 50k miles. It is a V6 so it does not have the power steering cooler.

 

1 If the vehicle is warmed up to operating temp before the flush is started the t state will be open and the old coolant will be flushed through then entire system with the new.2 If the shop that the OP went to did not remove the old coolant and clean the over flow container out (which it sounds like they didn't) that is probably were you are getting your sludge from.3 There is no way Dexcool will last 10 years even in a sealed system.You should at least check the ph or flush your coolant every 2 years or 24,000 miles. Dexcool is way to prone to gel up to run longer the a couple of years.To the OP remove the hose running from the overflow to the radiator and flush the overflow tank with a water hose till it is clean then put the hose back on and top off the coolant with a 50/50 mix and drive it for a couple of weeks and check it again.

 

To get it right, get the coupon GM is running right now for $100 (full flush and clean out the old) and get the Dexcool back in it. Too many erroneous posts on numerous boards about how bad Dexcool is. It is designed for our cars and it works! I have over 14 years of personal experience that Dexcool is perfectly fine if changed every few years or if you have very low miles even longer provided you get the PH level checked. I have owned 3 GM Dexcool cars since new, a '95 Transport minivan, a '96 Formula, and now my '01 T/A. All were and are flawless with Dexcool. Zero issues. If you run high, high miles and 8 years go by, you will get all kinds of sludge and problems. The biggest 'problem' with Dexcool was the notion that it was a 'lifetime' coolant. Very wrong as any service manager will tell you and what owners of Dexcool cars will tell you that followed that 'lifetime' advice. It must be changed or checked at the very least. $100 every 3-4 years is not too much maintenance costs for something so important as the cooling system. If you can 'professionally' do it yourself, then even cheaper, but you better know what you are doing. Leaving old stuff in is counterproductive.

 

It will open, thats true, but it will also close in about 1 minute after it opens. t-stats don't just stay open. Therefore the coolant flow STOPS. Its a slow, cheezy way to do it. Taking the t-stat out is the best way, by far, to flush the system completely.
Mosdt gunk and **** stays in the block and gets stuck in there. I had to flush my engine for over an hour to get all the black **** out when my factory power steering fluid cooler starting leaking into my coolant system. That stuff doesn't just flow out nicley...it takes awhile to get it all out.

He could also have a cracked radiator and getting tranny fluid into his coolant.

Wrong again. Its all about a sealed system.

I agree it should be checked. But I didn't add a drop of coolant to my bone stock TA from April 1998 till May 2002 when my 427ci went in. It was topped off and 100% clean as a whistle. Dexcool can easily last double that...but not if your system has any issues.

Thats ridiculous. 2 years and it gels up. Thats just hilarious. As I said, mine was 4 years old and crystal clean.

Do you realize how many average Joes or soccer moms would be broken down all over the country if Dexcool gelled up in 2 years. Give me a break man. There wouldn't be enough tow trucks to keep up with the broken down cars everywhere.


How about first flushing the entire system porperly, cleaning the over flow tank at the same time, then spending money on new Dexcool. Then not have to worry about for years and years.

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Does that thing have the tranny fluid lines going to the radiator? I don't know **** about the V6's.

The inside of the radiator could be cracked, its common.

If everything is ok....just do a proper flush.

Here's how I do it. Takes a couple minutes to set it up, then flush it, then a couple minutes to put the t-stat back in. Short of pulling engine plugs and spending alot of time that way, there is no better way to flush all the old coolant and dirt out.

-Cold engine.
-Remove radiator fill cap.
-Remove the t-stat from the housing. Leave the housing attached to the rubber radiator hose, just remove the 2 housing bolts (2-3 minute job).
-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 it. It'll drain faster with it off and that’s what you want. ((Buy a new petcock valve before starting this flush, sometimes they break when you remove them all the way just because they're cheap plastic, they're like $2.00))
-Take a hose and stick it in the radiator fill cap, running medium to high.
-Start the engine.
-Let it run for about 15-20 minutes or until the water is running out the drain CLEAR.
-When it does 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. Big clumps of black crap. Make sure the lines that go to the reservoir are also cleaned out. 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:
Start it up and let it run and warm up till the t-stat opens, you’ll see it flow in the radiator fill neck, once it starts to flow the level should drop down, immediately top it off with coolant/water. Then the flow will stop. 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. I always massage the upper and lower hoses while its warming up to help move the air bubble by the t-stat on the engine side of the t-stat. Squeeze it rapidly and fully like 20 times each until it starts to flow. Always works like a charm. Just keep checking your temp gauge until the t-stat opens to make sure it’s not 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 those hoses again. Then start the engine again and see if the t-stat will open.

 

1 The pressure from the flush machine pump will continue to hold the t state open till the flush is complete that is if the you broke into the system on the correct side of the t state.2 I have 2 late model GMs in the shop right now that the Dexcool gelled up in(sealed system) the heater core and guess what no heat. I do know how many average Joes and soccer Moms have problems with Dexcool.I just don't bang on a keyboard about cars I fix them daily.If you made it for 4 years with no issues good 4 you.You are correct in the sealed system is the key to making it last but it will not last 10 years (What a joke).Just ask all the 3.4 and 3.8 gm owners who had to replace there intake gaskets because of the 100,000 mile Dexcool.It is pretty apparent you live in a special place where you know all and GM never makes mistakes.When clearly you dont know what the hell your talking about.

 

Also, what are the risks of leaving it like this? Can it cause any major harm? I haven't noticed any issues or overheating but maybe because the damage isn't done yet?

 

fyi the green coolant used my shops is called "khameleon". we use it at our shop. its is designed to mix with any color, orange and red included. so mixing it will not cause it to turn brown, you probably have air trapped somewhere in your system