Dex cool

[c55asleep]

Changing out the upper, lower and some other hoses tomorrow and was wondering if dexcool is ok to use? Have about two gallons left over from my ctsv, but not sure if it's ok to use it or just use regular coolant. Thanks

 

[turbodave231]

If you have been using green coolant, I'd stick with it. All antifreeze is ethylene glycol based, but all flavors have different corrosion inhibitor packages. The green coolant has a silicate based corrosion inhibitor package. The silicate deposits itself on the interior surfaces of the cooling system. That's how the metal is protected.

Dexcool uses an organic acid as the corrosion inhibitor. The two inhibitor packages work in different ways. Mixing chemistry is like playing Russian Roulette with your cooling system. You don't know what you have for protection if you mix and match coolants.

On the same topic, I will never buy the Prestone "One size fits all" coolant for just this reason. No OEM manufacturer approves mixing the "one size fits all" coolants into their systems. The OEMs spent millions testing their systems with one coolant formula. Why try and second guess their decisions?

Those are my thoughts on the subject.

 

[charlief1]

Dexcool also has 1 other interesting thing. If it's heated and exposed to air, as if you run low, it will turn into a mud like residue. You're better off flushing the system clean with dawn dish washing detergent and then using the old green or universal type coolants. I've also seen the damage that dexcool can cause to head gaskets and intake gaskets. Do it once and don't use dexcool.

 

[c55asleep]

I will do a good flush and go with the green coolant. It had water mixed with rust. I do remember reading that GM had to change gaskets and other things when they started to use dex cool, but don't remember the exact details..

 

[charlief1]

Use dawn and you'll be surprised how much crap will come out. If it was muddy looking then you may have to do it 2 or 3 times to get it all out. Last one I did this way had chunks of rust come out and that's what sold me on using it. Very cheap and extremely effective.

 

[c55asleep]

Use dawn and you'll be surprised how much crap will come out. If it was muddy looking then you may have to do it 2 or 3 times to get it all out. Last one I did this way had chunks of rust come out and that's what sold me on using it. Very cheap and extremely effective.

I'll try that out. I've used cascade for heavy trucks cause it doesn't create foam.

 

[jim0207]

During the summer months I use RMI 25 with no coolant. Temps never exceed 190.

 

[novaderrik]

Dexcool also has 1 other interesting thing. If it's heated and exposed to air, as if you run low, it will turn into a mud like residue. You're better off flushing the system clean with dawn dish washing detergent and then using the old green or universal type coolants. I've also seen the damage that dexcool can cause to head gaskets and intake gaskets. Do it once and don't use dexcool.

the coolant will always be exposed to air in a TR because they don't have a totally closed coolant system- the overflow tank is vented to the atmosphere and will quickly get coated with a mud like sludge that will get sucked into the radiator as the coolant expands and contracts..

 

[turbodave231]

Charlie,

You are correct about the air/high temp problem with Dexcool. That problem has been acknowledged by GM.

The gasket eating properties are a myth. The real problem is that GM Powertrain designed some really crummy intake gaskets and they flat fail. When the cooling system gets low enough, the engine overheats and then the head gaskets fail. Those same engines used Dexcool ........and the Dexcool often gets incorrectly blamed. But, if you read it on the Internet, It must be true!!

I have Dexcool in my current Duramax equipped truck and used it in my last DMax truck. Never had the mud or any gasket problems in either....Why? Good gasket design and then system never ran low.

I have a friend who is the Service Manager at a CAT dealer. They regularly use liquid dishwasher detergent to flush diesel engine cooling systems. I've never tried it , but I'll bet it works well.

 

[c55asleep]

Charlie,

You are correct about the air/high temp problem with Dexcool. That problem has been acknowledged by GM.

The gasket eating properties are a myth. The real problem is that GM Powertrain designed some really crummy intake gaskets and they flat fail. When the cooling system gets low enough, the engine overheats and then the head gaskets fail. Those same engines used Dexcool ........and the Dexcool often gets incorrectly blamed. But, if you read it on the Internet, It must be true!!

I have Dexcool in my current Duramax equipped truck and used it in my last DMax truck. Never had the mud or any gasket problems in either....Why? Good gasket design and then system never ran low.

I have a friend who is the Service Manager at a CAT dealer. They regularly use liquid dishwasher detergent to flush diesel engine cooling systems. I've never tried it , but I'll bet it works well.

I've used dex cool on most of my cars but they were a lot newer than my GN. I wasn't sure if I should put it in this one for that same reason. I wasn't sure of the cause, but I know it was in the lines of it being about the gaskets.. I work on Mack trucks and we don't really use dishwasher cause it causes so much foam. You will be flushing it for hours lol.

 

[aminga]

Dex cool will also leach the lead out of the solder joints in the radiator.