12-24-06, 05:23 PM
I'm looking at a 96 and the owner says he got an oil change and a week later it started knocking. "It does have a motor knock, doesn't miss or skip a beat but the knock is loud enough to not drive. I got an oil change in it last week and after 1 week the car started to make that noise." Could it be from carbon buildup? Would it show up that fast if it was carbon?
Carbon build up aka "Cold Carbon Rap" will go away within 60 seconds or so after starting. If it is continuous, it is not likely CCR. I have had CCR show up overnight on my '97 Deville. Quieted down before I got out of the driveway. A dose of WOT keept it from returning for a long time.
12-27-06, 02:07 PM
^^ Agree. After the engine is warm, carbon doesn't knock anymore. There was/is an Eldorado for sale near me with a knock, for cheap. I checked it out thinking it was carbon, but after driving for a few minutes, it didn't go away.
I think a fellow member had a knocking sound. But his problem ended up throwing a rod in his engine! :eek: