LLY: Worried.. Coolant Question

[ShredLordXx]

Hi Guys,
I just bought my 04 Duramax LLY last week, and I thought it had Dex-cool in it, but while I was messing with my A/c system today, I noticed that it has green coolant in it, the previous owner told me that he had just finished changing the water pump, so I'm guessing that they refilled it with regular coolant. Should I be worried and change it?

Any info would be great!

 

[07keo02]

If it was completely flushed and now has green it is ok. If they are mixed at all (dex and green) it will cause issues.

 

[Huffy67]

This is why we use the global/universal antifreeze at work. It will mix with anything. It is green in color but will work with any make or model. If they used that, you should be fine. But if not, who knows. If your worried just do a coolant flush for some piece of mind.


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[ShredLordXx]

Yeah I'm not sure what's in it, I don't think its mixed together, it is an odd green color though. I just wasn't sure if it was safe to have green in it, considering it has only use dex-cool marked all over the place under the hood. lol

 

[ShredLordXx]

So if I were to go to the store and buy more coolant, should i stick to universal diesel green, or go back to dex-cool, I'm not even sure if I could go back to dex, I would probably get issues with the small amount left in the engine block.

 

[07keo02]

If your not positive whether Or not it's mixed you need to get it all out and fill up with whatever you desire. I have a long ongoing issue from sludge built up in my system from the previous owner mixing. I promise you don't want to deal with what it can do. There is green coolant out there these days with very similar properties to dexcool. If you go straight conventional green for a top off you may create more issues down the road.

 

[Huffy67]

Do not put dex cool back in it!!!!!!!!! If you wanna flush it you can use regular old green or whatever you prefer. That dex cool can be some bad stuff.


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[Awenta]

I'd take out the thermostats and flush everything with a hose. Then refill with final charge coolant. Or cat coolant.

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[ShredLordXx]

Yeah I dont think it's mixed, the guy had the engine appart then re-filled it, and when he had just got it back together the water pump failed and pissed coolant all over,he had to replace it and had to re-fill it again. Any recommendations of what product to put back in it if I were to flush it? I don't think they mixed any, one of the guys who fixed it up, is an actual diesel mechanic for international here where I live. So I'm hoping he had some common sense lol they take many duramax in for fleet service here.

 

[Huffy67]

Anything you want really. I got the cheap stuff at Walmart mart when I did mine.


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[ShredLordXx]

Nice, thanks for the help guys! I was just worried that green in the system would be a big no no, but i guess not lol

 

[Huffy67]

Mixing it with dex cool is the no no. As long as your flushing and filling with one type, you're good.


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[ShredLordXx]

Well i threw a straw down the res tank today, and to my dismay the coolant is orange!, if i shine it into the sun it seems to have maybe a greenish tinge, may just be the fluoresence of the orange I guess it does have dexcool in it, the green tinge concerns me a bit, I guess i will be doing an empty and refill. Or is dexcool in a clear cup with just a straw full, does it have a tinge of that sort?

 

[Huffy67]

I would drain, fill with water, run for a while, drain, fill with water, run for a while, drain, fill with your choice of straight antifreeze due to the remaining water in the block. That way you don't have to worry anymore


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[ShredLordXx]

Yeah I'm going to drain and refill it for sure next weekend, the whole water thing creeps me out just because it gets so cold here in the winter, but I know mixing a good anti freeze together will negate all undesired effects. Do you think I should stick with Dex-Cool Its on sale here, I haven't looked around to hard, but I'm not sure where to find CAT coolant or anything other exotic coolants of the such, we used to have a CAT facility down south a tad and they shut the plant down, I may be killed for whispering the name CAT lol

 

[07keo02]

Time to flush with plenty of water and get all the old out. I personally am going through this and I am going with zerox G05 coolant.

 

[ShredLordXx]

Cool fluid, I think I might just stick with dex, the truck has 364 thousand Kilometres, and has probably ran dex all its life, so unless I can find some other cool OAT Diesel coolant then I'll probably stick with it. How are you flushing yours, I was thinking of getting some big distilled water jugs from the grocery store and filling and emptying a few times.

 

[ShredLordXx]

Also with the water left in the block, how would I mix, do I still go along and mix 50/50

 

[Hot COCOAL]

Also with the water left in the block, how would I mix, do I still go along and mix 50/50

Technically, youre supposed to use distilled water to mix...also, if you are so inclined, there are drain plugs at the bottom of the block, rear/pass front/driver side...

If you pull the T-stats and drain plugs, flush the open system with a hose, then fill it with water and run it down the road for some miles and then drain again, you sould be good to go to final fill the system with Dex/water..."I THINK" you can buy both concentrate or pre-mix from GM

 

[Hot COCOAL]

FYI, there are several guys that have actually had the reault of the dredded sludge just from mixing with the left over residual in the system from a drain and fill...

Some guys have gone to great lengths (not limited to) running (diluted but strong mixture of) Simple Green in the coolant system for a short period to "chemically" remove/nullify whatever coolant they dont want in the system...its a time consumeing process but worth it as a precautionary measure IMHO