Dexcool problems?

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autogear
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Re: Dexcool problems?

Post by autogear »

My grandmothers Go-to-church-and-hairdresser 96 GMC Jimmy had 2 transmissions and a heatercore go because of the Dex-Cool problem. Details are sketchy but it was exhibiting problems when they were on vacation and a quick-lube joint did the cooling repair. My belief is they used the wrong coolant to top off the system. Soon after in our frigid winter, the trans went. Then the heater core. The shop that replaced the trans did flush the coolant (or at least charged for it). When the heater core plugged up in like negative 20 weather, I finally got the call to look at it. (I was in the dark about all this so far). Flushed everything and the junk that poured out of this pig was incredible. I never did get it all out. Ended up killing the replacement tranny (under warranty). Finally I replaced the cooling system from stem to stern and got her to sell the truck.
UGH never again. I doubt its really GM's fault. Sometimes they really don't take into account the budget conscious home mechanic or shop and perhaps the Dex-Cool was always too finicky to begin with.
Bellman
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Re: Dexcool problems?

Post by Bellman »

I always topped the wifes car off with a 50/50 mix of Dex-Cool.. Nothing else..

I wonder if the tap water I used caused the problem.. A study said that St. Louis has some of the best tap water in the country..

Also.. Like I said before.. The wifes car only had 70K miles on it when the low coolent light started coming on.. That was 2 years ago, and her car just broke 90K.. I am the original owner, and always maintain my vehicles very well..
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af2
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Re: Dexcool problems?

Post by af2 »

Bellman wrote: I wonder if the tap water I used caused the problem.. A study said that St. Louis has some of the best tap water in the country..
What the best tap water means I haven't a clue. :idea:
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Re: Dexcool problems?

Post by timinator »

There is an easy check for the condition of the Dexcool in your radiator. Connect your VOM to the negative terminal of your battery and put the positive lead into the coolant in the radiator. If it reads negative voltage the coolant is good. If it reads positive the cooling system has turned into a battery and is now plating the soft metal (aluminum) onto the cast iron. The pink slim usually indicates an air leak in the system. It turns darker the worse the air leak. I replace the plastic intake gaskets on trucks all the time for that reason. When you flush the cooling system the water drain plugs in the block must be removed. The block gets a sandlike material in it that needs to be flushed out. If you don't the Dexcool will go back to a positive voltage in a short period of time.
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af2
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Re: Dexcool problems?

Post by af2 »

timinator wrote:There is an easy check for the condition of the Dexcool in your radiator. Connect your VOM to the negative terminal of your battery and put the positive lead into the coolant in the radiator. If it reads negative voltage the coolant is good. If it reads positive the cooling system has turned into a battery and is now plating the soft metal (aluminum) onto the cast iron. The pink slim usually indicates an air leak in the system. It turns darker the worse the air leak. I replace the plastic intake gaskets on trucks all the time for that reason. When you flush the cooling system the water drain plugs in the block must be removed. The block gets a sandlike material in it that needs to be flushed out. If you don't the Dexcool will go back to a positive voltage in a short period of time.

Thank you!!!!!!!!!!!!!!!!
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Re: Dexcool problems?

Post by Dodge Freak »

timinator wrote:There is an easy check for the condition of the Dexcool in your radiator. Connect your VOM to the negative terminal of your battery and put the positive lead into the coolant in the radiator. If it reads negative voltage the coolant is good. If it reads positive the cooling system has turned into a battery and is now plating the soft metal (aluminum) onto the cast iron. The pink slim usually indicates an air leak in the system. It turns darker the worse the air leak. I replace the plastic intake gaskets on trucks all the time for that reason. When you flush the cooling system the water drain plugs in the block must be removed. The block gets a sandlike material in it that needs to be flushed out. If you don't the Dexcool will go back to a positive voltage in a short period of time.
I gotta do that tomorrow on the 2008 Saturn

Don't think gm uses the Dexcool now, I do trust Prestone more then gm
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Re: Dexcool problems?

Post by rally »

Wife has a 99 GMC Jimmy. 4.3 liter. The heater core has been a huge problem on these after talking to a GM Service Rep. We had to replace the heater core on this 99 Jimmy due to leakage. The service tech who replaced this said that dex-cool caused problems on these heater cores, actually eats the material over time. Recommended i use the old green anti-freeze when this was replaced, which i did. The service tech told me dex-cool was used for enviromental issues being safe for animals, but this dex-cool eats heater cores on these models, go figure.
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Re: Dexcool problems?

Post by stockcar5 »

rally wrote:Wife has a 99 GMC Jimmy. 4.3 liter. The heater core has been a huge problem on these after talking to a GM Service Rep. We had to replace the heater core on this 99 Jimmy due to leakage. The service tech who replaced this said that dex-cool caused problems on these heater cores, actually eats the material over time. Recommended i use the old green anti-freeze when this was replaced, which i did. The service tech told me dex-cool was used for enviromental issues being safe for animals, but this dex-cool eats heater cores on these models, go figure.
your rep was wrong. dexcool doesnt specifically corrode jimmy/blazer heater cores as they are made from the same material as nearly every other vehicle...they were just a poor design.
dexcool also is not safe for animals since it is Ethylene Glycol based like the green stuff. gm uses it for its extended life and it is still used in new gm vehicles.
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Re: Dexcool problems?

Post by SilverXJ »

Many of the all makes all models coolant are actually a clone of dexcool.
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Re: Dexcool problems?

Post by DaveMcLain »

It seems to me that I heard somewhere that one of Dexcool's problems was that for whatever reason it tended to break down/get bad if there was a very minor combustion leak into the cooling system. A leak so minor that it would never even be noticed but it would cause the Ph to change and the coolant to break down whereas the older coolant tolerated this condition much better. Could this be true?
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Re: Dexcool problems?

Post by novadude »

SilverXJ wrote:Many of the all makes all models coolant are actually a clone of dexcool.
+2

Prestone "All Makes All Models" coolant says right on the label thatg it includes 2EHA. This is the "evil" inhibitor blamed for all the problems with dexcool.
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Re: Dexcool problems?

Post by SilverXJ »

DaveMcLain wrote:It seems to me that I heard somewhere that one of Dexcool's problems was that for whatever reason it tended to break down/get bad if there was a very minor combustion leak into the cooling system. A leak so minor that it would never even be noticed but it would cause the Ph to change and the coolant to break down whereas the older coolant tolerated this condition much better. Could this be true?

Combustion, air leaks, other contamination all cause problems for Dexcool. IIRC there are some rad caps that are better than others for dexcool as well.
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Re: Dexcool problems?

Post by mike22l »

Dexcool = garbage.

It ate my water pump, ate the block heater core plug, three intake gaskets, the aluminum heater hose quick connect nipple front and back. This is all on one vehicle and yes the rad was grounded.
Had the same problem on my other vehicles also.....

I drain every vehicle now and put in the green and no problems at all...I still own the one truck and i put on 160000 miles after switching and not one problem.

Here's one for ya. I worked in at a major Truck company in Engineering doing design and I had the same argument with our cooling guy. I told him i've taken out the orange crap and never had a problem with the green...so...we experimented.....We used 2 trucks both 96 gmc 1/2 ton chevs with 30000miles on them...both got complete flushes and one had green and one had orange. They were both put out for service and the one with the green put on 70000 miles and the one with the orange put on 62000 miles....well the one with the orange had 2 intakes changed, 2 heater hose nipples changed, the intake had to be replaced because it ate the crap out of the aluminum and 2 core plugs. The one with the green stuff? Not one thing!....Nuf said

Yes we added 3 grounds on both vehicles. frame to engine and cab to engine and cab to frame
If you run the orange and everything looks good well...good for you...I had problems with it and real world tested it.

so what..you have to change the orange every 30000 miles so it doesnt eat the crap out of everything. why worry about it...switch to green.

As for the gewy jelly stuff....I put an intake on for a guy1 year ago and it got a complete coolant flush..i tried to talk him into green but he went orange....guess what..back one year later with an intake gasket that was all corroded and nasty...i just said..told ya so..he runs green now....and he switched his other vehicles over also...

Now before everybody gets all fired up...im just giving u my experiences with it. I know guys that say they dont have any problems with it. I know more that do.

phew...
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Re: Dexcool problems?

Post by mike22l »

Why worry about your orange going corrosive? go green...

now im done..promise
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Re: Dexcool problems?

Post by 1989TransAm »

"Sometimes they really don't take into account the budget conscious home mechanic or shop and perhaps the Dex-Cool was always too finicky to begin with."

I think that is the problem right there. That is why I switched back to the green stuff. Don't have to worry about it as much as you do with Dex-Cool.
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