Jim Grant's Tech Tips
'96 Chevy Silverado, Intake Manifold Leak
The intake manifold gasket failed in my '96 Chevy Silverado. What caused
the leak? Was it the incompatibility of the Dex-Cool anti-freeze and the
gasket or mixing the red Dex-Cool antifreeze with normal green antifreeze?
- John Bradley
First, you should never
mix the GM type red/orange colored antifreeze Dex-Cool with the green
anti-freeze that most people are familiar with. The green anti-freeze
will cause the red/orange Dex-Cool to degrade and not perform as designed.
Now there are some concerns that you should be aware of. We have found
that Dex-Cool, which is rated for 5 years or 100k miles, is not always
making it to the 5 yr. or 100k mark. This coolant can go bad and when
it does it gets real nasty and creates a pile of problems. I guess what
I'm saying is do not be lolled in to believing that service is not required.
Regular testing and inspection of the cooling system with Dex-Cool is
a must. As we all know, what works great in the lab often has contrasting
results in the real world.