I guess I did not post the question right. My car has a blown Head gasket that is allowing a bit of coolent to go through the exhaust and is messing up the sensors. The car has 90,000 miles
and my question was is it worth the money to have the head gasket replaced or am I throwing good money after bad and should just replace the whole engine?.....the coolent does not appear to be in the oil ....yet.
Thanks, Bob

 

Blown head gaskets happen, and unless engine damage has occurred or there are signs the engine is nearing the end of it's useful life it's just a repair job.

I'd do a compression (or even better a leakdown) test on the engine...accounting for the cylinder w/ the leakage being a tad out of spec, and make the decision. The leaky cylinder will be easy to identify, the spark plug will be really really clean.

If the engine checks out, do the head gasket swap and be sure both the head surface and block deck surface are true. If the block surface is warped or otherwise irregular...decision point is reached, and the engine is coming out for either rebuild or replacement.