tcr1016

I read that the DEX-COOLŽ coolant has been known to ruin gaskets and seals in a forum. Is this true??? I just bought my truck with 56,000 miles and want to change all fluids, but am worried about what I read about DEX-COOLŽ coolant. I have the state required GMC warranty till 100K miles, so I do not want to void the warranty.

What coolant do most use without voiding the warranty, and what intervals do you change it??

wellmax

if it were me i would at least change out the orange coolant, flush system and install new orange coolant if you are concerned.

I do not know what they mean when some say orange coolant is fine if it properly serviced.

mine has the yellow coolant after i had the intake manifold gaskets changed out.

gm service shops made a mint on changing the manifold gaskets.

DoubleO7

What year do you have?
Supposedly Dex-Cool was "bad" due to age and air infiltraion via the rad cap and/or the coolant expansion tank allowed to suck air.

I am in the process of changing the intake gaskets on my 99 5.7L Tahoe.
No wonder those OEM gaskets leak. There is but a 1/8" bead of silicone on some sort of falling apart "carrier" that makes up the gaskets.
At the heads.
Then a bead of I bet the cheapest silicone available at the front and back ends of the block where the intake touches. With no grooves no nothin to prevent the silscone from getting squished out.

Before I got around to changing the gaskets, I was using Prestone AF to top it off as it leaked out of the intake.
The Prestone I used claims to be ready for use in any vehicle running any color of coolant. No warning about mixing colors, etc.
Some said adding green/yellow to the orange/pink stuff cause it to gell up.
I did not find that tho happen with mine.

wellmax

double07,

it happen to my buddy, 96 modle truck, he mixed green coolant with his orange, the whole system turned to mud. had to have the motor, radiator all boiled out.

if you want to change from orange back to green, you need to flush system good!! before you add the green coolant.

however, the yellow will mix with either.

birdie

i would think you would use the coolant your owner manual tells you to use. my 09 4.3,v6 reg cab. takes dex-cool, the orange one.

in2pro

My .02cents
Is that its not the Dex that causes problems its the failure to maintain/change the coolant regularly that causes problems.
Any coolant can become acidic if not maintained...

LARIDERS

I have never had problems with dex-cool. I use it for all my gm cars and trucks. It is best to use the coolant it calls for and follow the maintenance plan given.