Volvo: volvo 850 1997 not starting, head gasket repair, volvo 850 1997

Question
QUESTION: I recently bought a 1997 volvo 850 non-turbo. It was running hot when i first bought it and was having to pull over to let it cool off quite a few times during my attempts to fix the problem by flushing the radiator and replacing the thermastat. i finally put some head gasket repair in the coolant and it fixed the overheating probem. i drove it 250 miles, stopped and attempted to start it not 5 min later and it wouldnt start. i had the starter rebuilt, replaced the plugs and battery. it barely started but when it did it ran fine all the 300 miles to get where i was going. once again 15 min after i stopped, it didnt start again. just turns over and sometimes sounds like its about to start but then doesnt. i replaced the cam sensor, rpm sensor, coil pack, distributor cap, rotor, and cleaned connections. still nothing. car runs fine after it starts, but since this started it's only started 3 times. any ideas?

ANSWER: Joe,
I would say that the over heating warped the head or blew out the head gasket and now the compression is too low to fire it up. Do a compression test and cylinder leakage test. You appear to have spark and fuel so then maybe the compression is getting weak due to the warpage or bad gasket.

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QUESTION: i will do the compression test next, i pulled each wire out yesterday and tested the spark, it only sparks about once a second on each wire. i read to test the distibuter you can pul the cap and see if the rotor turns when cranking. i am going to do that as well, but if the spark is really weak, how does it get enough spark to stay running when it finally did start the few times? thanks for your response.

Answer
Joe,
Why the car started and ran a few times, I can not tell you. On a warmer day or a day the the air was dencer there was enought of everything needed to run the car maybe? I don't know. I was going with the information that you told me and if I had the car in front of me these are things that I would do. I can tell you that more than once I have seen a car that was overheated and that was enought to lower the compression so the engine would not start.