Cold Engine Knockkkk!!!
Melting Slicks
Joined: Jun 2004
Posts: 3,439
Likes: 6
From: Newark, DE
St. Jude Donor '06
Originally Posted by samhane
If the oil filter did cure the problem then why wouldn't the dealership suggest this or place it in a service bulletin.
So true....
Melting Slicks
Joined: Nov 2004
Posts: 2,275
Likes: 5
From: Lake Oswego, Near Portland Oregon
It seems to me that there might be some issues that sound similar to cold piston slap that also occur at startup and pre-warmed engine conditions, like hydralic lifters taking a while to pump up, or worse yet, dry rods. This wouls explain why some drovers are experiencing the noise go away with high instant flow filters. All the oil in the world shouldn't have any effect on true piston rocking, unless it is actually sprayed onto the bore as a 'cushion' until the pistons swell up to fit better and not bang around. Rod bearings would respond instantly to full oil pressure, lifters very quickly thereafter. Piston pins are another question....some engines have pins press fit in the rod and some are full floating, loose in both the rod and the piston. I remember a race engine builder telling me once that if that interface gets sloppy that all kinds of noise can result. Beyond that, I am begining to stretch my knowledge of engine physics.
7th Gear
Joined: Jan 2002
Posts: 7
Likes: 0
From: Derry NH
my $.02 on piston slap
I have a 2001 coupe. Bought it new just 4 years ago and now has 25.5K miles on it. I've heard the piston slap sound for a while now, when the motor is cold and only between 1400-1600 RPM till it warms up, and took the car in the other day just so I have it documented. Anyway, the service rep gave me the Chevy party line: "it's normal, won't hurt the motor". Of course, like everyone else, I'm not entirely inclined to believe this but at this point, with 25.5K on it, it runs great and I'm using maybe 1 quart every 1K miles (which, again as we all know, Chevy says is normal). But if it makes anyone feel any better, I had a '95 Chevy S10 with the 2.3 4-cylinder and it had a pretty loud piston slap when cold. I took it to the dealer when it had around 23K miles on it and got the same story: piston slap, won't hurt it. I REALLY didn't believe them at the time but I drove that thing for 4 more years and put 100K miles on it and it ran perfectly when I traded it in. The noise never got worse, went away when it warmed up, the thing never used/burned/dripped a drop of oil. So, I know what it is and it's documented and like a number of others in here, I'll just live with it.
Racer
Joined: Jul 2004
Posts: 278
Likes: 0
From: Tallahassee FLorida
I should be noted that the engine ticking people sometimes hear from their engine is the fuel injectors, not the pistons or the valves. My injectors are as loud as can be no matter what the temperature of my engine is.
