Intake manifold gasket leaks
According to the majority of people I've talked to, my engine is prone to this type of damage, either because of bad gasket design, bad formula of the Dex-Cool, which is the standard coolant used in these vehicles, for both reasons, ..or maybe for none of the above reasons. While the causes for an intake manifold gasket leak may be different and depend on various factors, this page is dedicated to the repair, which always involves replacing the intake manifold gasket.
How do you know that your intake manifold gasket has developed a leak? For the non-mechanical people among you, this type of leak can be internal, external, or both at the same time.
Coolant seeps through the broken intake manifold gasket to the outside of the engine. Most times this happens where the aluminum intake manifold sits on the straight portion of the engine block. There is no actual gasket at that location, but a gasket substitute formed by a bead of RTV.
If your leak is bad, you will see orange coolant constantly dripping under your truck, but if you have a tiny leak, you may just smell the coolant, but not see it. This is due to the coolant evaporating almost instantly as it touches the hot engine block. As the engine cools down you might see a few drops under your vehicle.
Coolant seeps through the damaged gasket to the inside of the engine, mixing with motor oil. If you suspect an internal leak, check your oil dipstick. If you see that your oil has a milkshake-like consistency and there is rusty looking residue inside your oil filler cap, than.. most likely you are right and you have coolant leaking into the crankcase.
So.. which type of leak is better?
There is no type of intake manifold leak that is better than the other. Both internal and external intake manifold gasket leaks are bad for your vehicle. Both types of leaks have at least one thing in common: Coolant disappears mysteriously (at first), then the disappearance is more and more obvious. Sometimes you can find the source of the leak right away and sometimes you don't.. Be patient, run your step-by-step diagnostics and you will eventually find the exact location of the leak. I found mine!