Spark plug missing

impalabill1970 · #1 (**permalink**) 01-21-09, 11:39 AM

My '99 STS blew out a sparkplug yesterday. New plug put back in OK - threads seem OK, but did not do complete inspection. Has anyone experienced this before?

EcSTSatic · #2 (**permalink**) 01-21-09, 11:45 AM

You're in the wrong forum but to answer, it happened to me a long time ago on my '64 GMC p/u. I may not have tightened them it all the way after a tune-up. It might also be possible to cross-thread them and only think they are screwed in completely.

C&C · #3 (**permalink**) 01-21-09, 12:08 PM

Vibration can do funny things; glad you didn't do any harm to your cylinder head. Probably was never fully tightened when last spark plug was changed. Had the plug been cross threaded, definite evidence of damaged threads should have been noticeable.

Stoneage_Caddy · #4 (**permalink**) 01-24-09, 03:33 PM

grampa had one of the old buick speicals with the all alumium engine , used to evacuate all 8 spark plugs at 130 mph ...

as long as the threads looked ok you should be fine , never know why could be it wasnt tight , or had 10 gallons of anti seize on it ....too many reasons for it to happen ...but if your sure the threads looked ok and the new one went in ok you should be fine , but if it comes out you beatter go find some goodys headache powder

chubbyranger · #5 (**permalink**) 01-25-09, 11:42 AM

FSM torque spec for 99 spark plugs is 11 ft lbs. Don't overcrank the new one to make it stay or you could end up with another similar problem.