Dex cool causing engine poblems?

[Horse_gal_jen]

General Motors Corp. Class Action Rejected
Detroit, MI: (Feb-24-07) A class action lawsuit was filed against the auto company for allegedly selling millions of vehicles prone to problems caused by Dex-Cool coolant. The lawsuit sought to represent owners of more than 35 million cars and trucks built by GM between 1995 and 2004. Those vehicles use orange-colored Dex-Cool coolant, which the plaintiffs claimed was responsible for numerous engine problems, especially radiator sludge and failed head gaskets.

US District Judge Patrick Murphy has ruled that GM will not face a national class action. State courts in Michigan and California already have rejected statewide class actions. [DETROIT FREE PRESS: DEX-COOL REJECTED]


anyone heard anything about this? any truth to it?

[Duramaster]

I have had vehicles that used DEXCOOL. No problems. The important thing is to keep the cooling system full. If a leak developes which then allows air into the cooling system............. well then that is when problems would start to occur.


We had numerous S/T trucks in the shop with plugged radiator cores. The problem was because the RADIATOR cap itself would develope a bad seal which allowed the engine to push the coolant out into the overflow bottle,but the cap had such a bad seal that the engine could not draw the coolant back into the radiator. Often referred to as Mississippi mud. The defective cap could be easily spotted on the earlier vehicels..... It was the plastic style cap that locked using the "push and half twist" lock. As far as the newer vehicles (GMC TRUCKS that is) that use the screw on caps, I have not seen any problems.

[More Power]

Here's a clip from an article I wrote in 2003 about Dex-Cool:


We have learned that an air/coolant interface within the engine or cooling system could create an environment for aluminum or iron corrosion when using Dex-Cool. Not coincidentally, GM incorporated an air-bleed screw in the 6.5L & Duramax 6600 thermostat housing. This provides a means to vent air from the cooling system. Additionally, the coolant surge tank is also designed to remove air from the cooling system. So, unless there is some sort of engine or cooling system failure (or inadequate initial fill), there should never be an air/coolant interface in your 6.5 or Duramax cooling system.

A recent class-action suit has been brought against GM for cooling system corrosion involving 4.3L engines used in GM's late model Blazer, Jimmy, Olds Bravada, Sonoma, and S10 pickups. As reported in the May 22, 2003 issue of The Columbus Dispatch, GM stated that it "is aware of concerns about Dex-Cool. However, those problems involve customers who ran their cooling systems for an "extended period of time" -- 15,000-20,000 miles - with low coolant levels." GM went on to say that "There are 35 million to 40 million GM vehicles on the road that use Dex-Cool, and the overwhelming majority have experienced no problems with the cooling system."

As stated earlier, we have also identified a problem with a coolant/air interface, and the potential for corrosion as a result. We also know that cooling system performance (when properly filled with a 50% Dex-Cool/distilled water solution) will surpass those using a green silicated ethylene glycol coolant.

I should also point out that since 2003, when the above was written, there has been no significant problem with Dex-Cool when used in the either the GM 6.5L turbodiesel or the Duramax. In fact, I believe there would be more cooling system problems if we were still using the green stuff.

Jim

[Mark Rinker]

No good deed (or in this case, relatively 'new' technology) goes unpunished. If you don't believe me - google all the negative reviews on Windows VISTA, hybrid cars, biodiesel, etc. :)

There is a large percentage of people that simply don't embrace change, and will resist most attempts for technology to move forward, away from their comfort zone. The whole DexCool thing seems to be more of that, than fact, in my opinion.

[Rabbler]

Not that I'm disagreeing with anything said but NEW doesn't always = BETTER.

[More Power]

Not that I'm disagreeing with anything said but NEW doesn't always = BETTER.

Dex isn't necessarily new - it's been in GM vehicles since 1996. In the case of Dex, it's better than the green stuff because ....

1- it has a longer service life - 5 years or 150,000 miles.
2- it provides a longer water pump seal life.
3- it offers a better coefficient of heat transfer.
4- in most cases, it offers better protection against cooling system corrosion.
5- NARSA (National Automotive Radiator Service Association) recommends its continued use. NARSA is an independent organization that assists the radiator rebuild shops nationwide.

Jim

[killerbee]

Dexcool is a confusing topic. There doesn't even seem to be just one formula either, though I have no factual data on it.

I no longer use dexcool, though my reasons are different from anyone who has switched. I came by way of factual information that dexcool is not very good at inhibiting pump cavitation during high flow scenarios. The price for this is a lower flow rate, and some water pump damage, which is now showing up on some of the water pumps I have seen in high milegae vehicles, nothing catastrophic mind you.

And for some reason, Ford rejected dex in its testing for the diesel. You even find "no dexcool" placards on its degas bottle and cap. So I suspect the decision was not a political one, but who knows.

After doing some homework, I settled on using the G-05 low silicate formula at 40%. It is the same formula used in Ford Gold. I just add a little red food coloring, you can't tell the difference.

[Mark Rinker]

So what about DexCool would cause it to be more likely to cavitate - or release gas from suspension under high flow?

Would adding a surfactant help?

[killerbee]

The honest answer is I don't know. I could try to find out. Not sure that it is a surface tension issue.

I am fairly certain that the silicate free chemistry is the key part. But it has been awhile.

In any event, I don't think dex is problematic for most, but I do know it is incompatible with green silicate formulas. The worst thing you can do to dex, is top off with old green, some type of precipitate sets up in the passages after a time. Beware of Jiffy Lube

[More Power]

The worst thing you can do to dex, is top off with old green, some type of precipitate sets up in the passages after a time. Beware of Jiffy Lube

The worst thing that will happen, according my research (done 4 years ago), is that mixing coolants containing carboxylate corrosion inhibitors with those containing silicates will shorten the service cycle to that of silicated ethylene glycol.

Jim

[Horse_gal_jen]

thanks for the information all.

We use Dex cool in all 4 of our gm vehicles and haven't had problems.

I recently had the problem that duramaster described where my coolant resevoir cap failed and was causing the system to purge all the coolant.

my sister in law however has a venture which is the same motor as my grand am and she recently had a problem with her head gasket.

the system was causing bubbles to form up into her resevoir tank. she took it to a shaudy mechanic who insisted it wasn't the head gasket but rather the intake gasket and she spent a fortune replacing that, only to find out it was in fact the head gasket.

they do NOT look after their vehicles, they ignore warning signs of something going wrong until it is too late and they are in trouble. so honestly I can see why they had this problem with a 3 yr old van.

however, my sister in law prefers to blame the dex-cool for the problem isntead of her ignorance so I will just let her have her own opinion, I just wanted to see what others had heard about the problem.

I really appreciate all the info, I prefer to be informed on this sort of thing cause i am certain my sister in law will start a debate about it and i want to be able to give her an informed response.
Thanks all!

[copperhead]

I have to say that I recently had to replace the water pump on my '03 Duramax and I have never seen cleaner coolant passages than I did on my dex-cool'ed duramax.

[JohnC]

Nothing but Dexcool for 12 years now and nary a single problem.

I'm no expert, but GM seems to have an issue with the intake manifolds on the V-6 engines, I think more because the're running EGR through plastic than anything else. The mechanic's guess was not unwarranted, unless he actually looked at the vehicle... Don't see how the bubbles could come from the intake.

So you in-law's logic is that Dexcool made the mechanic stupid? ;)

[killerbee]

I have to say that I recently had to replace the water pump on my '03 Duramax and I have never seen cleaner coolant passages than I did on my dex-cool'ed duramax.

what was the failure point?

[MaxACL]

I just replaced my waterpump at 240,000... Seal failure. I still use the Dex and change it every 100,000 miles.

Water pump $230.00 Labor 2 hrs.

Mike

[MaxACL]

On Edit:

I just replaced my water pump at 240,000... Seal failure. I still use the Dex and change it every 100,000 miles.

Water pump $230.00 Labor 2 hrs.

By the way, there is an air cavity somewhere in the engine that takes a while to get rid of. The mechanic that replaced my water pump is an experienced DuraMax hand and showed me that if you loosen the thermostat housing bolt, it will "burp" the trapped air.

Mike

[More Power]

I suspect at least some of the water pump seal leaks we hear about are due to excessive cooling system pressure as a result of head gasket or injector cup seal leaks.

I checked a couple coolant tank caps recently by pressing on the relief valve with a blunt tool (remove the cap and place it upside down on a table). I wanted to see how much pressure the spring exerted - I was just curious.... What I discovered was that the sealing valve was somewhat stuck. It took more pressure on the tool to unseat the valve than just compressing the spring should require. Unseating the valve a second time was much easier. I wondered if a sticking relief valve would allow more than 15-psi to build in the cooling system, which could also impact water pump seal life...

BTW - the high point in an LB7 cooling system is the coolant hose that connects to the turbocharger.

Jim

[EdHale]

the water pump on the '98 6.5 Suburban I sold to my son in law is still going strong at 265,000. Ed