1995 Bmw 325is E36 Engine Knock, Intermittent Sputtering.
Posted in Exhaust and Mufflers | Asked on Jul 31, 2010
The knock sounds like a diesel, or an exhaust leak. The sputtering/hesitation is totally intermittent. Some days it runs great ‘n others its dropping 200rpm approx randomly then picking it back up.
My diagnosis so far: It isn’t one of the 6 ignition coils,
The knock sound goes away if I remove the spark plug from Cylinder 5 and replace it (I typically also clean it). The knock sound will completely go away, you can’t strain to hear it at all. That last for like 2-3 days then it comes back.
One more thing i’ve noticed is there are 4 bolts on the head in between the ignition coils and one of them seemed to slowly be leaking oil so I go to tighten them all down, and they’re all tight except that one. It seems it may be stripped or something because it doesn’t ever get tight.
I figured that if that bolt is getting loose it would explain the exhaust leak (knock?) and the lack of compression could explain the intermittent hesitation because it would be catalyzed by the heat and expanding of the metal. Any ideas? Experts have suggested it could be VANOS, or my lifters. I know its not my lifters …
Worst case scenario is damaged valves?
There are 2 Answers
Do the following: FIrst, locate, remove, and clean your IDLE AIR CONTROL VALVE. THis controls fuel mixture at low speeds. Secondly, use Butyl cello-solve to de-sludge the inside of your engine. Lastly, start using ELF oil, BMW specifications, to continue cleaning the engine out as you drive it. Mobil One is good, too.
I think it sounds like your injectors are being blocked by gunk. I dont think injector cleaner will work but you could try it. As for the knocking sound it could be the exhaust manifold missing a bolt maybe. If it was a lifter it would not stop knocking. Oh, and you prolly need a valve cover gasket. Hope this helps.