Sorry Dex Cool haters

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Originally Posted By: roadrunner1
I did not comment to contribute to this thread because I am a "Dex-Cool Hater".
One of your coolants jobs is to help protect the seal of the water pump, and I realize the age of the vehichle posted above.

With saying that I have more than a few friends with Chevrolet products that have had early water pump failures, one Tahoe with approx. 35,000 mi. they bought new.
I don't know if the seal failure is coolant related or poor quality control at the time of assembly or sub-par water pumps

To start a post stating that the cooling system looked great at just over 100,000 mi. because you are in there replacing the water pump sounds like you are overlooking the obvious. Something caused the seal failure.


That pump was redesigned and it is best to use that factory pump.
 
I've noticed quite a few premature WP failures on late model Toyota's recently. I've been wondering if it is because of the switch to the Pink extended life coolant losing it's additive qualities/effectiveness. I don't remember this being a problem when the Red fluid was in vogue changing at 30K intervals.

My latest project has been trying to investigate how coolant could be contaminating the engine oil in my daughter's 2008 Avalanche 5.3L engine. I came across these two articles about DexCool and other extended life coolants:

http://www.sancarlosradiator.com/dex-cool.htm

http://www.sancarlosradiator.com/antifreeze_coolant.htm

They helped me understand some of the problems that the industry is having.
 
I'm not jumping on the Dex-Cool bandwagon. My current daily driver, 2002 Monta Carlo SS with a 3.8L experienced a UIM(Upper Intake Manifold) gasket failure. Resulting in a UMI failure. Replaced the gasket and UIM with GM's "New Design". Been fine and circulating Dex-Cool for 100k+ miles.

My girlfriend has an 2002 Century 3.1L. Typical leaky intake manifold gaskets. They were also replaced with GM's new design gaskets and the intake was reinstalled with GM's updated installation procedure. That was at 23k miles. Car now has 48k. Doing fine.

Not going to point out the elephant in the room but...both cars came factory filled with Dex-Cool and both had intake gaskets fail...
 
My '05 Saturn Vue 2.2L came with Dexcool. Bought it last year w/ 81k miles. Changed it out over a few months via two radiator drain/fills with more Dex - no issues and the cleanest looking coolant I've ever replaced. Probably could have left it in till 100k easily.
Seems more engine related than coolant.
 
Originally Posted By: OhioGuy82
I'm not jumping on the Dex-Cool bandwagon. My current daily driver, 2002 Monta Carlo SS with a 3.8L experienced a UIM(Upper Intake Manifold) gasket failure. Resulting in a UMI failure. Replaced the gasket and UIM with GM's "New Design". Been fine and circulating Dex-Cool for 100k+ miles.

My girlfriend has an 2002 Century 3.1L. Typical leaky intake manifold gaskets. They were also replaced with GM's new design gaskets and the intake was reinstalled with GM's updated installation procedure. That was at 23k miles. Car now has 48k. Doing fine.

Not going to point out the elephant in the room but...both cars came factory filled with Dex-Cool and both had intake gaskets fail...


Both cars were maintained by you, and both had intake gaskets fail. Is it your fault? These engines both have a known issue with intake manifold gaskets. Replacement, updated gaskets are available.
 
Originally Posted By: INDYMAC
I've noticed quite a few premature WP failures on late model Toyota's recently. I've been wondering if it is because of the switch to the Pink extended life coolant losing it's additive qualities/effectiveness. I don't remember this being a problem when the Red fluid was in vogue changing at 30K intervals.
Do you see any differences in the water pumps used vs the pumps in the "Red" years? Also there is a difference in chemistry between red and pink.
 
Originally Posted By: cchase
Originally Posted By: LeakySeals
New (to the family) 08 Grand Pix purchased with 69k 6 mos ago. I've never seen coolant that bad. None of my Asian cars did that no matter how many miles were on the coolant. Forget sludge, it feels like sand is in there. Red/orange blobs hard and crumbly. No doubt thats wearing out the pump seal and plugging up the system. 2 drains with peak global lifetime it was still pretty bad. Started adding RMI-25 and phew, problem mostly solved. Did the PO change the coolant? Doesn't look that way. But I'm sorry, there's no excuse for that coolant condition at 69k.


Usually the red/orange blobs you describe are "Stop Leak" tabs or something along those lines. I have read that they are put in from the factory in some vehicles (not just GM).
Thanks. Wish I'd known that before I went through all the trouble to get it out. I researched it before drawing any conclusions, but the net is full of complaints. So I guess in this case, I believed it.
33.gif
 
Originally Posted By: LeakySeals
Originally Posted By: INDYMAC
I've noticed quite a few premature WP failures on late model Toyota's recently. I've been wondering if it is because of the switch to the Pink extended life coolant losing it's additive qualities/effectiveness. I don't remember this being a problem when the Red fluid was in vogue changing at 30K intervals.
Do you see any differences in the water pumps used vs the pumps in the "Red" years? Also there is a difference in chemistry between red and pink.


I have not seen the pumps, just read about leaking on various forums of different models as early as 15K miles. Here's an example from a Tundra forum:

http://www.tundrasolutions.com/forums/tundra/222753-5-7-leaking-water-pump-comon/

I remember having my timing belt changed for the first time on my 2000 Tundra at a dealership. It had red fluid. I asked the service advisor if I should have my water pump changed at the same time (70K miles). He said it wasn't neccessary because he hadn't seen one fail before 135K miles. Mine was starting to leak at 142K miles when I had the belt changed again.
 
Originally Posted By: OhioGuy82
Not going to point out the elephant in the room but...both cars came factory filled with Dex-Cool and both had intake gaskets fail...


It's people like this who perpetuate the myth that dex is a bad coolant. He even outlined what actually failed!

Yes, it is absolutely true that GM spec'd some really poor gaskets. And my heart goes out to the folks who bought a bad one. The expense and disappointment is real. But there are gazillions (ahem, that is facetious) of dex vehicles on the road and it works very well.

We rarely do a water pump before 200k miles plus on our fleet trucks, and some go much farther!
 
Both of the vehicles I mentioned also received new design parts and updated procedures. They have not had any type of issues since the repair.

I just installed new valve cover gaskets on the Monte Carlo During the installation had to move the tensioner, lost some coolant. I topped the car off with Dex-Cool. Didn't think twice about it.
 
I've used it in five vehicles with mixed, but I believe in hindsight predictable, results.

It was terrible for the 1999 Suburban where it filled the coolant passages of the 5.7 Vortec engine with brown sludge, took out the intake manifold gasket, leaked into the oil and caused engine problems from there. The 5.7 wasn't designed for Dexcool and GM should have never used it in that application.

It has been great in the 2000, 2001, 2003 and 2005 Cadillac Northstar engines that my family put something close to 500,000 miles on without a problem. I did replace it and put in a new thermostat in each car every 3-4 years, but never had a water pump failure or any other kind of cooling system problem. We still have the 2003 and 2005 Devilles, so "knock on wood." The Cadillac Northstar engine was designed to use Dexcool and it works well for them.
 
Originally Posted By: ronrackley
The Cadillac Northstar engine was designed to use Dexcool and it works well for them.


My '99 Northstar (Caddy STS) tuned its dexcool coolant into brown sludge. The GM dealer cleaned it out and refilled with dexcool and replaced the radiator cap and put in the GM stop leak stuff (Bar's Stop Leak equivalent, the crushed walnut shell stuff). Later, the engine overheated and the head gasket blew at only 110K miles. The Northstars are well known to blow head gaskets, not sure if it is just a mediocre design in general or its the fault of dexcool in that application. The engine did have a new water pump too due to leaking seals.
To compound the problem, a head gasket change requires timecert installation. You are looking at well over $2000 to replace the head gaskets, possibly on an engine that is sludged up with brown gunk.

Call me crazy, but dexcool is never going near one of my cars again. Pretty much every coolant sludge story is about dexcool, nothing else. All my cars run Peak Global Lifetime now.
 
I work at a shop and its 95% GM vehicles needing intake gaskets and heater cores flushed 2-3 a week easy.I have had good luck cleaning these systems with TSP but it takes a few days of driving to work. You can actually see the globs of dexsludge in the coolant.
 
Originally Posted By: ronrackley

It was terrible for the 1999 Suburban where it filled the coolant passages of the 5.7 Vortec engine with brown sludge, took out the intake manifold gasket, leaked into the oil and caused engine problems from there. The 5.7 wasn't designed for Dexcool and GM should have never used it in that application.


More anecdotal mythology. We have raised and ruined a ton of 5.7's in service vans and trucks all factory filled with dex. Never a single issue.

These are maintenance issues, nothing more. Dex is even used by Ford now. Nothing wrong with it.
 
Originally Posted By: maybehabitformin
I have had good luck cleaning these systems with TSP ...


Which product do you use that has TSP, or you use plain TSP e.g. DAP brand?
 
Originally Posted By: Raybo
Its a rare car forum where you find people who say Dex Cool is OK.
Cost GM millions in the class action Dex Cool lawsuit.

Never met a mechanic who didn't say get that orange [censored] out of there.

http://www.girardgibbs.com/dexcool/


Probably more to do with the fact that the vast majority of car forums are just echo chambers of other forums and a great example of how to spread mis-information about a variety of topics.

What does a mechanic know about coolant chemical make-up and root cause analysis on (for example) gasket failure? In most cases, likely nothing.
 
My 4.3 is spotless running Dex, and Ive never had any indication of sludge, build up or anything. Then again, Ive never let anyone top it up with green.

Newer vehicles with pressurized tanks dont seem to have the dex issues, AFAIK.
 
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