Jim Grant's Tech Tips '96 Chevy Silverado, Intake Manifold Leak
Q: 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
A: 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.