I am a bit skeptical myself. The used car dealer I bought the car from sells and services used Volvos and said he has never replaced a flywheel. A new starter did not fix the problem. The Volvo mechanic cleaned the crankcase sensor( it has a lot of metal filings on it) to no avail. He said the flywheel is "chewed up". The car will crank for a few seconds, then stop, and continue cranking until it fires up. It appears that either the starter looses connection with the flywheel or power is interrupted briefly. It does always eventually start--at least so far. Could it be a bad crankcase(rpm) sensor?