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Re: CEL upon engine failure Posted by Larry West [Email]  (#1140)  [Profile/Gallery]
(more from Larry West) on Thu, 2 Apr 2009 05:45:54
In Reply to: CEL upon engine failure, nbgardens, Thu, 2 Apr 2009 04:01:56 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Pistons don't crack of their own accord, usually, and if they did, it would happen in the piston's very early life.
Pistons can crack due to stresses in the combustion chamber. If you ran a fuel that burned significantly hotter than gasoline in a gas motor, this could be a problem (I once had a friend who ran jet fuel in his motorcycle...can you say meltdown?). However, that would take some time, and presumably would set a code (or several) in the engine management.
The second thing that would crack a piston is mechanical. This could be from a number of sources. Foreign Object Damage would be the engine sucking in something from the outside, or perhaps a part that falls into the combustion chamber during work on the motor. The next thing would be domestic object damage, where a part of the motor in the combustion chamber (like a valve head) breaks off, and pounds the piston to smithereens.
That last item can happen on the V6 in the 9000, NG900 & 9-5 if the timing belt breaks. This V6 is an "interference" motor, where by the valves and pistons will damage one another if the cam timing is not correct.
A mechanical issue may or may not set a light fast enough for the driver to react to, or fast enough to happen before the engine stops completely.
If you have a V6, and the timing belt is broken, along with the cracked piston, it is 99 44/100 % certain the belt broke first, taking the piston with it. Not the other way around. Were the piston to crack by itself, it would likely set many codes in the ECU, and the CEL, but if the timing belt was fine, then the motor shouldn't stop mechanically.
The V6 in the 9-5 should be fine for 60,000 miles on a timing belt, tensioner & pulley set. But much beyond that, and the owner risks an extremely expensive repair.
_______________________________________ Current: 2002 9-5 Aero Kombi Cosmic Blue 2000 9-5 SE sedan, Imola Red 1990 900S Rose Quartz, Auto Past: 1999 9-5 LPT Combi 1999 9-5 LPT sedan 2002 9-5 Arc 1990 900 5-speed 1986 900 turbo Convertible 1991 9000 turbo 1980 99 GLi 1986 900 turbo 1986 900 S 1991 900 turbo 1984 900 turbo 1976 99 GL
, Thu, 2 Apr 2009 08:09:09, Thu, 2 Apr 2009 05:45:54 <-- Viewing This Message
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