Neon new head gasket/not starting - chris562
The head gasket on my 1998 Neon failed a couple of months ago.

My regular repair man has replaced the gasket and the car ran for 15-20 minutes then stopped whilst they were flushing out the cooling system. I understand the compression dropped because the hydraulic tappets over presurised.

Since then it has resisted all attempts to get it running.

The car has been taken to a main dealer who reckoned no problems were showing up on their computer diagnostics - they offered to remove the head again but were talking very large sums of money.

I am assured the timing has not slipped during re-asembly. Both the crank sensor and the cam sensor have been replaced but still the car fails to run.
Neon new head gasket/not starting - Civic8
I would guess the timing belt slipped due to incorrect tensioning.from what you said belt jumped and threw valve timing out.would suggest a compression test is done this will confirm whether you have bent valves.I may be wrong and hope so.
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Was mech1
Neon new head gasket/not starting - Peter D
You say they were flushing out the cooling system, do you mean they were using a flushing agaent or running a hose pipe through the system on a hot engine. If so there is your problem, the cold water in the hot head has cracked it may be in several places. If you crank it do you have a spark and fuel if so and the bely timing is correct then it does not sound good. Regards Peter