More Dexcool fun

[Chris142]

This 02 Blazer with a 4.3L rolled into my shop today. I asked the owner about it's history.

He bought it new. @80K he put a water pump on it and bought new Dexcool @ the Chevy dealer. @ 105K he had to replace the intake manifold gaskets, he also replaced the radiator cap and got more new Dexcool from the dealer.

He said that he is the only one thats ever worked on it so there is no chance of it been contaminated by Jiffy lube.

He said that it was clean @ 105K. Now has 149K.

You guys can draw your own conclusions.

 

[StevieC]

It had to be overheated, or the Transmission cooler is leaking into the Anti-freeze or bad head gasket/head... Something's not right. I have used Dex-Cool coolant in my previous cars and my neighbour uses it with 100,000km changes and it never looks like this...

 

[-Clayton-]

Stop leak?

 

[Chris142]

Originally Posted By: StevieC
It had to be overheated, or the Transmission cooler is leaking into the Anti-freeze or bad head gasket/head... Something's not right. I have used Dex-Cool coolant in my previous cars and my neighbour uses it with 100,000km changes and it never looks like this...
No trans fluid in the coolant/mud.It would be pink and not brown. No stop leak added.

@105K when he replaced the intake manifold gaskets all he did was gaskets and new Dex with distilled water. He said that it has not overheated. I did a block test on it and that came up negative for hydrocarbons in the cooling system.

 

[StevieC]

Can you send some of the coolant for UOA type test to see what contaminants are in it. Could it be that he filled it with Dex-Cool at one point then added some other similar Dex-cool product that wasn't actually Dex-cool and the two chemicals reacted?

Like I said my neighbour has 2 GM vehicles full of Dex-Cool and he changes it every 100,000 and it always comes out clean.

 

[sciphi]

Eww...

I can see a very light form of that in a system that was flushed completely until the water ran clear for a minute and then topped off with a Dex-clone that has similar chemistry.

 

[Chris142]

Originally Posted By: StevieC
Can you send some of the coolant for UOA type test to see what contaminants are in it. Could it be that he filled it with Dex-Cool at one point then added some other similar Dex-cool product that wasn't actually Dex-cool and the two chemicals reacted?

Like I said my neighbour has 2 GM vehicles full of Dex-Cool and he changes it every 100,000 and it always comes out clean.
Thats all fine but I work at a Radiator shop and this is a daily event. He claims that he only used Dexcool from the dealer in it. He's sposed to bring it back on Wednesday for me to flush it. If he does I'll try to grab a sample.

 

[StevieC]

I believe you.. My dad is a retired mechanic of 35 years and had used Dex-Cool in customers cars without any problems... ???

 

[cronk]

That does look like oil contamination. Blazers do have engine oil coolers in the radiator as well as trans oil coolers.
I'm not sticking up for Dex-cool, I flush it out of every vehicle I own and put Peak in. It just appears that there is more to the problem than just the Dex-cool.

 

[Chris142]

Oil contamination turns the coolant grey

 

[Firehawk409]

I'm sure my 94 firebird came with dexcool but I have flushed my coolant mulitiple times, way before it ever hit 100k, and it still always comes out brown and gunky. I have taken out my radiator and totally flushed it out. I also flushed out my engine block. Just recently i stuck the waterhose to the heater core line and flushed it till it came out super clear. Still comes out looking like brown gunk. It doesnt bother me to much though. My temp is always stable and it has never over heated on me.

 

[StevieC]

Originally Posted By: Chris142
Oil contamination turns the coolant grey
Not with most Dex-cool stuff, it turns it brown I have seen this a few times...

I put only the green glycol stuff in because I find that it stands up a bit better if the trannie cooler leaks etc... and it doesn't get too gooey like the dex-cool does...

IMO.

 

[onion]

I just don't understand the denial... it's not like these people work for GM. What stake do ya'll have in defending Dexcool?

If a successful class action lawsuit, the near-universal contempt of experienced mechanics who encounter dex-sludge routinely, readily available visual evidence (do a yahoo image search on "dex sludge" sometime), and 2EHA's well-established gasket-dissolving properties are not adequate to convince these folks that Dexcool has very real propensity to turn into a nasty, sticky sludge under relatively common (if not ideal) conditions... then I suppose nothing short of a thorough sludging of THEIR OWN Dexcool system will convince them.

Good luck with that. Personally, I'll be using a readily available alternative that suffers none of these inherent problems.

 

[StevieC]

I didn't know about the lawsuits, and only seen very few sludgers most of which were caused by a bad trannie cooler in the rad... I never ever seen a dex-cool system sludged.. Interesting... Thanks for telling!

 

[Maritime Storm]

I've seen a few S10/Blazers like this. I thinks think it's got more to do with the set-up on that particular cooling system than Dexcool in general. I've never seen the cooling system on a Saturn, Cavalier/Sunfire like this. Dexcool doesn't like Oxygen, in unsealed systems it does this, ie those with a non-pressurized overflow tank.

 

[The Critic]

Originally Posted By: Maritime Storm
I've seen a few S10/Blazers like this. I thinks think it's got more to do with the set-up on that particular cooling system than Dexcool in general. I've never seen the cooling system on a Saturn, Cavalier/Sunfire like this. Dexcool doesn't like Oxygen, in unsealed systems it does this, ie those with a non-pressurized overflow tank.

Exactly.

In over 122,000 miles on various silicate-free and Dex-Cool antifreezes, my Saturn's cooling system is still clean. Nothing like this at all. When I changed the radiator hoses a few weeks ago, only a small amount of sediment was found at the bottom of the system. So in good faith, I refilled with Prestone Dex-Cool.

Could water quality be an issue here? I wonder if the deposits have something to do with the hard water that Dex-Cool is sometimes mixed with.

 

[Dan55]

I have used Dexcool (Prestone) in my 93 SL2 for over 200K and no problems. I replaced the radiator because of a cracked trans coolant fitting and it was clean inside after 11 yrs.

 

[Donald]

Originally Posted By: The Critic
Originally Posted By: Maritime Storm
I've seen a few S10/Blazers like this. I thinks think it's got more to do with the set-up on that particular cooling system than Dexcool in general. I've never seen the cooling system on a Saturn, Cavalier/Sunfire like this. Dexcool doesn't like Oxygen, in unsealed systems it does this, ie those with a non-pressurized overflow tank.

Exactly.

In over 122,000 miles on various silicate-free and Dex-Cool antifreezes, my Saturn's cooling system is still clean. Nothing like this at all. When I changed the radiator hoses a few weeks ago, only a small amount of sediment was found at the bottom of the system. So in good faith, I refilled with Prestone Dex-Cool.

Could water quality be an issue here? I wonder if the deposits have something to do with the hard water that Dex-Cool is sometimes mixed with.


Why didn't you switch to a G-05? Did not want to do a complete flush. G-05 is as good as DexCool at being an antifreeze, roughly same price and no risk of sludge.

 

[The Critic]

Originally Posted By: Donald
Why didn't you switch to a G-05? Did not want to do a complete flush. G-05 is as good as DexCool at being an antifreeze, roughly same price and no risk of sludge.

I did perform a complete flush-- I drained the coolant and refilled water and Prestone Super Radiator Flush and idled for 45 minutes, then drained and refilled twice with water.

I just wanted an easy to obtain over the counter coolant. Dex-Cool issues are rare with Saturns. If I had a GM 4.3 or something of that nature, then yes, I would've seriously considered switching to something else. Also, if I wasn't around and the car needed cooling system work performed, the shop would probably refill with Dex-Cool. And I wouldn't want two different fluids in the system, so to play it safe, I decided to stick with Dex-Cool.

 

[PeteTheFarmer]

Originally Posted By: The Critic
Dex-Cool issues are rare with Saturns.

Is your engine made of aluminum? I suspect part of the problem with Dex-Cool is that it doesn't protect iron well, and when air gets into the system rust happens quickly.