Thread: dex-coolant BAD !!

Thank you SyntheticShield . You gave me probably the best advise yet . changed out my dex-coolant to regular green coolant . when draining the dex-coolant there was sooooooo much dex-gunk/sand coming out . i went and paid $90.00 after seeing how much started coming out to have my radiator flushed . the guy at the shop told me the same thing when he was flushing it out there was alot more of the dex-gunk/sand that came out . car runs about 5* colder now that all that stuff came out . thanks for that advice !

I will have to post pics of my overflow bottle it is extremely tarnished, I can't imagine wha my radiator looks like. what brand green coolant are you guys using? Why does it say not to use anything but dexcool in the owners manual also?

I know you cannot mix it, I mixed them up in an expiriment in a cup one day to see why it says do not mix, other than the obvious reasons. Needless to say I didn't want that happening in my motor.

I guess the being easier on aluminum is why then.

First, bayareagtp, you are welcome. I know Im not an isolated case and I know that if I had the time and resources I could pull nearly everyones radiator that is running Dex-Cool and find that Dex Sand. You should have saved some of it and let it dry out for a few days and then put a small amount of sand in one hand that Dex crap in another and I bet you cant tell the difference.

You did a complete flush and that is a really good thing, because as Toasty mentioned you cannot mix Dex Cool and the green coolants. They are two different types. If I recall correctly, Dex Cool is a HOAT technology (Hybrid Organic Acid Technology) and the green coolants are OAT (Organic Acid Technology). I dont recall the differences between the two right now, but you can search google and find out.

Quite frankly, if you can afford it, the new G-06 coolant is supposed to be the cats meow. I know Propylene Glycol is very good at reducing wear in the cooling system too, but also suffers from higher cost.

I will tell you now, get your hands on a coolant filter and install it right away. It is worth the money and will go a long way to keeping your coolant clean. More so, it serves a better purpose in keeping a great deal of contamination from reaching and settling in the radiator.

Toasty, check your radiator cap. If you see that gelatin type stuff there, you can bet its in the rest of the system and some of it is hardening and making its way into the bottom of your radiator and accumulating. If you dont have any, you would literally be the exception to the rule.

i will admit i was very hesitant at first when i heard this , then i took off my radiator cap and saw all that gunk built up and decided i might as well try it . i am glad i went to the shop and had the guys down there flush the system . i would hate to see jello in my radiator .

You guys are aware that that the brownish gunk is the sealant tablets GM puts in the cooling system from the factory. Those tablets also will leave a caoting on the overflow bottle as well. As long as you don't let your coolant system run low, and do more frequent flushing than was the manual suggests, it should be fine.

That said back when I bought my SS, it was used with 9Kmiles on it. As a part of the purchase aggreement I had them flush the system install green and put in writing ( service manager) that doing so would NOT void my warranty. He said it would be no problem as long as I had the system flush every 30K miles.

I've learned quite a bit since that time, and would most likely stay with Dex if given the oportunity again...since I'm green in this car it will stay. All of our other cars have dex and I'm not woried about them at all.

disclaimer: Your results may vary.

Indeed, Im going to have to call you on that one, well at least based on my experience. Aware that GM used sealing tabs I had mine flushed at a shop professionally. I still had the gelling issue. I started seeing the gel on the cap again so I had it flushed again. Still kept getting the gel on the cap.

Ive seen the GM sealing tabs and I will tell you until the day Im in a grave what I pulled out of the radiator was not sealing tabs. I bought some that I was going to put in there to try and delay the needed LIM gasket repair but I never put them in. With my coolant filter I can top off the radiator much better than most because the filter is on the upper hose. In fact I don't have the bleed air out of the system nearly as much as I did before installing it. So I know its not air exposure that caused the issue in my car. Though Dex cool seems to be WAY overly sensitive to air, much more than any green coolant Ive used in the past. In fact I NEVER EVER had a cooling system related failure until I got my Grand Prix with Dex Cool in it. And prior to this Grand Prix, I paid little attention to cooling system maintenance.

Im not trying to start anything, so please dont take it that way, but I took every step I could to make sure that cooling system was clean and topped off as much as possible. I may be a fluke, but I don't think I am. Furthermore, if GM puts something in there that gels like that (referencing the cooling tabs) then I would not think very highly of their decision.

Originally Posted by Toasty

eh, i do wonder if they're even using the sealing tabs anymore.

i recall now (it's been awhile) that early on in the dexcool life cycle, the tabs were used, but for some reason, i am now thinking they may have stopped. at some point

They are still using them. My 04 had the brown sealing stuff around the cap and stained overflow bottle.

Those that have the nasty gel, and I know what that is, normally is caused from not flushing soon enough, contamination, some type of breech in the system or not keeping the system full. EDITED the rest: because I looked more like an A** than being helpful.

Originally Posted by Reptile

I've had 4 vehichles with Dex-Cool in it....and have yet to have a gel issue or anything like that. Take that for what it's worth. I'm tired of arguing about it.

cranky old ...er young fart. This falls into that which is oil, oil filter, intake, is better catagory. My question for you since you are a GM mechanic, is could the results people have with this be related to the health of the vehicle?

My daughters Cavalier has 70k+ miles and her dex is just as clear orange as can be. I don't think they needed sealing tabs in the Cavi engine and the reason why hers looks so much better than any Impala or GP that I've seen.
I've been told by a couple of other GM tech's the 3.4 and 3.8 cooling systems were notorious for leaking and instead of redesigning, GM put the tablets in as a preventive measure. Can you confirm or deny?

Brian, sorry I didn't get the job correctly and thanks for your take on what the differences. My wifes Venture (3.4) had to have the LIM gasket replaced on it. GM priced it out at $2000 to replace. I'm going to help my son replace his as I can smell coolant when he pulls in the garage. However no way would I attempt this on a van. We wound up having Midas do it for $700 IIRC. Man was I ticked off about that.

Yeah my silverados never had any of this "dirt" or "sand" leftover ever and I have owned 5 silverados. I am going to say, lee, your theory sounds reasonable.