when do you know when you need new head gaskets or know when you blow one out?

 

Taking the head off to inspect is the definitive way, but a leakdown test to find lost compression is a good idea, and coolant in the oil is a sign that something has to come apart.

 

The most common type of head gasket failure is combustion chamber to coolant passage. The common symptom of this failure is sudden and severe overheating. We verify this type of head gasket failure by testing for HC either in the radiator or more commonly in the coolant reservoir. For this test I like to use my 4 gas analyser but you can also purchase a chemical test kit at the auto parts store. A severe cumbustion to coolant failure will create a steady stream of exhaust gas bubbles in the coolant reservoir. If you see this you need head gaskets.