Knocking noise at start up since vehicle was new. GM sent me a letter in 2001 stating that this was normal. I have 217,000 miles on the vehicle now, and the same knocking noise at start up that I did at day one. But I just read about someone with a similar problem who installed a higher volume oil pump out of a Camero, and the knocking noise ceased. GM COULDN'T FIX THIS ? Should I eventually rebuild this engine, I will definitely be giving this remedy a try.
Update from Jun 7, 2013: Bosch makes an oil filter with a check valve inside, it keeps oil up in the engine where it is needed for start up instead of draining back into the pan when engine is turned off. Noise is virtually gone. Still a good idea to let engine warm up a minute though. AC Delco also makes a similar filter for about $4, where the Bosch is about $12.
What a problem this has been. I have taken it to 4 different mechanic shops to get fixed and none can give a good answer as to the problem. I even had the complete bottom of the engine removed and had the oil pump replaced and still nothing. I must have paid at least 3,000 dollars in repairs and it"s still making that ugly diesel sound every morning. If Chevrolet Motor Co. says that it's not a problem then why don't they make it right and put a new engine in our Suburban. I love Suburbans and I love me Chevy's but come on MAN! Somebody help me..
This is what GM calls CSK (cold start knock) or piston slap. It is supposedly caused by differences in expansion of metals used to manufacture the block, pistons, heads, etc. The noise is caused by the piston having too much clearance in the cylinder and consequently banging against the cylinder walls. After expansion under temperature the noise goes away. The problem has apparently existed for a long time but was amplified by the use of skirt-less pistons up until 2001-2002 year. My 01 Suburban sounds like a diesel in the morning, but fortunately the noise eventually goes away. The dealer told me about all the above and that the only real solution was to replace the engine. GM says it should not affect performance or durability, I however, do not like the thought of pistons banging around... that cannot be good.
when i start the car up in the morning when it is cold it makes a knocking noise until it is warm and then it goes away. The dealership said it is just carbon between the rings and there is nothing to worry about. they suggested i use some lucas oil additive next time i change the oil but they assure me there is no problem. i sure hate the noise!!!!
A D V E R T I S E M E N T S
Drive it, just don't rev the engine till initial warm up is done, about 1 minute
- dstevenson53, Sarasota, FL, US