Dex-cool???

[Beast388]

I've been reading some of the horror stories about Dex-cool on the internet. There seems to be numerous stories about sludge, short gasket life, and corrosion throughout many current GM engines.

What is the consensus among the CK5 guys who drive new GM vehicles? Any problems? Has anybody switched to the regular green coolant with any ill effects?

I ask because I just bought the wife an '01 Pontiac Montana and it currently has the Dex-cool in it. The intake gaskets were replaced in '04.

 

[Robert D]

By Dex-Cool are you referring to the Orange fluid? After having the old Porsche in a shop to have the H20 pump and timing belt replaced they gave it back with orange fluid, I thought it was made by Prestone...The fluid didn't seem to cause harm to my motor, and I left it in for ~40k miles (while adding a bit here and there).

 

[Emmettology 101]

I have a 99 Tahoe with Dex-cool. It currently needs the intake gaskets replaced. Mentioned to my friend about switching to regular anti-freeze and he said stick with the Dex-cool. Then something about the horror stories and problems were from the first year vehicles that ran dex-cool. *shrug*


**EDIT** Forgot to add that my friend is a GM Tech.

 

[randy88k5]

I have a few friends that work at the dealerships. Many many vehicles have come in for cooling related issues. The mechanics are now instructed to flush the dex-cool/etended life out and put the conventional green antifreeze back in.

 

[Emmettology 101]

Check my edit.

 

[colbystephens]

From what I understand, there is a replacement hybrid cooland which is intended for these vehicles which will not sludge up. It is basically what the dex-cool was intended to do, only it actually does it. I've switched my 95 s series blazer over to the green coolant with no problems. Just be sure you flush your system really well and get all the dex-cool out. I've read in an article in a book printed by The Diesel Page that it's ok to mix these two coolants in extremely minor amounts - but this will drastically reduce teh life of the coolant. The point - if you're going to do it, do it really well.

 

[txfiremank5]

I had just about very water related failure (except the water neck) in my 97 with Dex-Crap. I chose to flush it all and replace it with the green. I plan to do my wifes 01 Tahoe too, now that it's out of warranty.

Maybe it's not bad.. I don't know. But the only real advantage to it is it's long life. Screw that.. I'll be content changing it every couple of years. It's worth the peace of mind.

Also, for anyone who does swap over.. I was told to do a VERY THOROUGH FLUSH .. otherwise the dex-crap will gell with the green.

I've been green for a few years now with no problems at all.

 

[spydermonkey454]

gm has never instructed its techs to use anything other than dexcool if thats what it came with from the factory.

the 3.1/3.4's have intake gasket problems.

the only reason they sludge up is because the coolant level gets low.

honestly 3 years is pretty good on a set of intake gaskets. my wifes car had only 30k on it when the intake gaskets started leaking. still under warranty.

i would make sure that they put the updated gaskets on it though. and should have replaced the intake bolts.

89017279 updated intake gaskets
11588915 updated short bolts
11588914 updated long bolts

and they have to be torqued in a very specific pattern
go back and ask your dealer if these parts were used.
reference bulletin #03-06-01-010B

steve

 

[JIM88K5]

Don't belive anything you read on the internet .

It is air in the system that causes the sludge. Leaky intake, bad cap ect...

 

[beater_k20]

gm has never instructed its techs to use anything other than dexcool if thats what it came with from the factory.

the 3.1/3.4's have intake gasket problems.

tell that to the hundreds, upon hundreds of trucks that went through 3 local dealerships equipped with Vortec 4.3s, 5.0s, and 5.7s. not a single one of them left the shop with anything but conventional green glycol based antifreeze. i worked the parts counter at one, and had friends who worked at the other two as techs. i personally sold at least 500 sets of the 5.0/5.7 gaskets in the 2 years that i worked for the dealership. we couldnt keep the damned things on the shelf. it got so bad at one point that i moved them from their intended spot in the stockroom, to a shelf directly below my teminal. dex cool is hell on your engine if you develop a leak, as when it reacts with air it makes a nasty mess, almost as if it were trying to seal the leak. contact with green antifreeze makes a nice concoction with a consistence much like that of oh say, pudding. not exaclty what i like attempting to flow through my radiator.

another GM wonder is the NA 3800 Series II intake plenum. PN 17113136 if i remember correctly. they burn out at the EGR port, apparently its not a good idea to route hot exhaust gas through a composite plenum. used to sell about 2-3 of those a week too.

 

[sweetk30]

bad intake gaskets are caused by the stupid morons that made them from plastic.


the old school paper stuff rarly went bad as much as these stupid new plastic ones go bad. you mean to tell me that some of the gaskets that blow out at under 35k miles is o.k.

sorry i wont buy new car/truck anymore . all this plastic is breaking faster than a tuneup is done. what the f

i have flushed some out and gone green no problems. and to some have you tryed to get the build up out of the dexcool rads with all the sludge? that stuff is like glue.

 

[dodgedude99]

i had a friend that had a radiator replaced on his jeep cherokee, the dude filled it back up with dexcool, without flushing out the etylene glycol.

needless to say 6 months later i was replacing the radiator because the radiator was sludged up with some brown crud.

we flushed the system and filled it back up with good ole green.

 

[ryan22re]

tell that to the hundreds, upon hundreds of trucks that went through 3 local dealerships equipped with Vortec 4.3s, 5.0s, and 5.7s. not a single one of them left the shop with anything but conventional green glycol based antifreeze. i worked the parts counter at one, and had friends who worked at the other two as techs. i personally sold at least 500 sets of the 5.0/5.7 gaskets in the 2 years that i worked for the dealership. we couldnt keep the damned things on the shelf. it got so bad at one point that i moved them from their intended spot in the stockroom, to a shelf directly below my teminal. dex cool is hell on your engine if you develop a leak, as when it reacts with air it makes a nasty mess, almost as if it were trying to seal the leak. contact with green antifreeze makes a nice concoction with a consistence much like that of oh say, pudding. not exaclty what i like attempting to flow through my radiator.

another GM wonder is the NA 3800 Series II intake plenum. PN 17113136 if i remember correctly. they burn out at the EGR port, apparently its not a good idea to route hot exhaust gas through a composite plenum. used to sell about 2-3 of those a week too.

since the intake gaskets for the 3.1/3.4's, the 4.3/5.0/5.7, and even the 3800 have been revised, we do alot less intake gaskets. the new style gaskets have metal inserts that prevent the gaskets from crushing (always from overtightening the bolts). also the new bolts are designed to work together with the gaskets to clamp the intake, but not allow the bolts to be overtorqued.

why is the sludge a problem? if you keep track of your vehicle, and its coolant level, air in the system shouldnt be a problem at all. the majority of the vehicles in question probably never get their hoods opened but one every 5000 or more miles. i find it hard to beleive that your water pump springs a leak on the way home and you develop sludge in the system. the sludge is developed over time.

so its gm fault that the majority of its customers can't open their hood and look at the coolant level?

ryan

 

[73k10sub]

Dex Cool

My '98 C2500 and '99 Yukon, both 5.7L, developed various leaks at about the same mileage . My mechanic, who specializes in GM vehicles only, flushed and went back with the green stuff after the repairs.

 

[beater_k20]

why is the sludge a problem? if you keep track of your vehicle, and its coolant level, air in the system shouldnt be a problem at all. the majority of the vehicles in question probably never get their hoods opened but one every 5000 or more miles. i find it hard to beleive that your water pump springs a leak on the way home and you develop sludge in the system. the sludge is developed over time.

so its gm fault that the majority of its customers can't open their hood and look at the coolant level?

in short, yes it is GM's fault. not everyone is as mechanically inclined as your average, or hell, your less than average CK5er. working at Jiffy Lube for 4 years (3 yrs in HS, and 1 as a weekend job when i was in college) i have seen some pretty crazy stuff. had a lady come in with low coolant, told her about it, and the 2.99 it would cost to top it off. she ok'd it. after paying her bill, she walked outside, opened the hood, removed the oil cap. she then proceded to ream me a new posterior orifice for not adding coolant to her car. when i kindly pointed out the radiator cap and the reserve bottle, she was ok with the coolant. she then commenced to yet another reaming for not filling it with oil. why? because she couldnt see it through the oil cap hole. took me a while to get her to understand that you check it with the dipstick. then there's the guys who come in, and when asked what weight of oil they prefer, trying to be cool, they respond, "WD-40". or how about the guy whose temp guage was reading hot, so he too removed the oil cap, and filled the crankcase with pure water. couldnt figure out why it was knocking, spewing the brown milky fluid all over the place, and still overheating. still not sure how he managed to get it to run with all of the water in the crankcase. ended up being nothing we could do for that one, the motor was trashed, all for a 10.00 lower radiator hose that sprung a leak. not everyone out there knows how to maintain a vehicle, so they resort to Jiffy Lube type places, and 99% of them will refuse "extra" services, no matter how badly they are in need.

 

[beater_k20]

i said "in short" at the beginning of that last post.

 

[ryan22re]

i agree.

most people spend more time reading a cell phone instruction manual then the owners manual.

an ounce of prevention weighs a ton.


ryan

 

[sled_dog]

eh, most of the GM techs at school(most of my teachers are ex-GM techs) agree, flush the crap and go green.

The BIG problem I have found is this, when you NEED anti-freeze, most places don't have dex-cool.

Surprise my 97 C2500 with a 5.7 blew an intake gasket on the way to Long Island. Too far from home and not yet there, so I had to limp it to the Island. Well everywhere I stopped along the way for water and anti-freeze, NONE of them had Dex-Cool. Needless to say my ATF was a nice brown, after a while it was green as the Dex-Cool disappeared out the front of the block.

 

[jhellwig]

The only thing bad I have heard about the stuff is that it turns to an acid after 3 or 4 years. But if I recal aren't you supposed to change you antifreeze every 2 to 3 years? All you realy need to do is keep an eye on the ph and it whould be fine.

 

[sled_dog]

The only thing bad I have heard about the stuff is that it turns to an acid after 3 or 4 years. But if I recal aren't you supposed to change you antifreeze every 2 to 3 years? All you realy need to do is keep an eye on the ph and it whould be fine.

yeah but Dex-Cool is suppossed to be long lasting anti-freeze.