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Re: Not a Saab, but a general car question... Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Fri, 12 Apr 2002 10:30:23
In Reply to: Not a Saab, but a general car question..., Joe98, Fri, 12 Apr 2002 10:17:28 Members do not see ads below this line. - Help Keep This Site Online - Signup |
I've seen this happen for three reasons -
(1) the obvious one - the plug got loose and blew out. This normally happens if the plug wasn't put in tight enough, as plugs tend to get more frozen with time. But temperature excursions can loosen things up.
(2) Plug too tight. Huh? The plug is held in by the threads. If the plug goes in too tight or goes in cocked, it can strip the threads. Stripped threads don't hold well - the plug is held in only by a little bit of metal. Over time and temperature changes, that little bit of metal holding things in can't hold up to the constant pounding of combustion, and out it goes.
(3). The center core of the plug got blown out. The plug is a metal base that screws in, with a center ceramic core that holds the electrode. If the ceramic core breaks for some reason - thermal shock, manufacturing defect, etc. - the pressure from the cylinder can blow it out. The metal base will still be in the head, but the center electrode is gone.
In general, (1) and (3) are easy to fix - put a new spark plug in. For (2), you need to put a helicoil in to the head to repair the stripped threads.
Good luck!
posted by 140.157.4...
, Fri, 12 Apr 2002 10:30:23 <-- Viewing This Message, Fri, 12 Apr 2002 15:57:57
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