Probably the biggest and most well known problem to affect SC/XR7 owners is
that of blowing head gaskets. When the 3.8L V6 was being upgraded and
beefed up for use in the SC/XR7, the cylinder heads were altered. They used
smaller coolant passages so that more metal could be put into the head thus
making it stronger. This restriction of coolant flow allows the heads to run
hotter than usual. The SC/XR7 also uses a unique lower intake that creates a
restriction in flow of coolant through the rear of the heads. Given the fact that
most SC/XR7ís make anywhere from 11-12psi stock and up to 15psi modified,
this can really put a lot of stress on the cylinder heads thus causing the gaskets
to blow out.

How you look at this situation will depend on how bad you feel about it. It is
an annoyance that some SC/XR7ís donít make it to 100,000 miles without
blowing head gaskets, but there is an optimistic way to view this. If cylinder
head pressures get too high, there needs to be a way to relieve this pressure. It
is relatively inexpensive to replace a couple gaskets as opposed to rebuilding an
engine. Therefore, most people view the head gasket as a safety valve. It
would be better to blow out this low cost item rather than bend a rod or cause
greater internal damage because the pressure had nowhere to go.

Many of the head gasket failures that occur on the 3.8L motor are the result of
improper changes the owner makes or because of poor maintenance. Other
questions within the FAQ section clearly show that installing a smaller
supercharger pulley will definitely increase your chance of blowing the head
gaskets if the car still has its stock exhaust system. Secondly, engine coolant
should be changed every two years to keep electrolysis at bay. Because of
dissimilar metals between the cylinder head (aluminum) and the engine block
(cast iron), the coolant will actually begin to attack gaskets if it is not changed
on a regular basis.