Head gasket and check engine light in 2001 Subaru Forester on 2001 Subaru Forester

The check engine light came on unexpectedly with a code of P0420. The system was reset and the light has not come back on.

A month later the car needs a new head gasket. How long can I continue to drive the car without doing any major damage?

Are the two problems related or could these be two separate expensive repairs?

Asked by for the 2001 Subaru Forester
1 answer
first of all, resetting the light fixes nothing. the problem is still there. the 420 is a cat code and yes, it is expensive. the converter assembly is about 950 and the labor is 1 hour.

the overheating and head gasket need immediate attention as you will damage the internals of the motor by continuing driving. it is expensive as well. i would plan on 1500 and up.