05-03-07, 04:13 PM
Hey guys I need serious help, just the other day my engine started knocking, so i brought back home, i was a little low on oil but not enough for it seize or anything like that. I would usauly the engine needs to be replaced but the knock isnt their all the time, only when i start it up and when its in low gear, if only could help with any ideals that would be great
05-03-07, 04:36 PM
Search the archives and technical threads for "knock", "carbon knock", "cold knock" and a few other N* quirks. Depending on how you drive, you may have a carbon buildup which, in a N* with minimal quench area above the piston, leads to a cold "rap". A few judicious WOT runs may clear the situation. The other possibility is some sort of fuel/timing glitch. Pull codes and see if there is a timing/PCM code set. Did you just fuel up ? Try a tank of 93 with a slug of Chevron Techron fuel additive from your local station or auto chain store. Running a N* a quart low is not normally cause for concern - I habitually run my '02 a half quart low and have essentially zero oil usage. (3000 mi.+/qt.) One of the main jobs of oil in a N* is for COOLING!
05-03-07, 05:15 PM
Thanks Sub, Ill Look into the carbon Knock Thing,
If it is only at cold start up, sounds like dry lifters and goes away in 60 seconds or so, the problem is cold carbon rap. The cure is WOT.
I have a 94 SLS N* VIN Y, had the same symptoms, hard knock when at idle, no knock when at speed or hard acceleration. Was unfortunately a spun bearing, I replaced with a used motor, to costly to rebuild. Good luck!!