Tell me about your "Piston slap"

kevinmach1 · November 1, 2005

My 2002 Yukon XL 8100 has it and the dealership says its "Normal". It only does it when the engine is cold, and is fine once it warms up. It sounds horrible, and it can't be good for the engine. Anyone else had this problem, and what have you done about it? I have 60K on it, and I have an extended warranty, but if it's "normal" the warranty won't cover it.

What do you think.

I found a website at pistonslap dot com, check it out sometime.

Kevin

DanW · November 19, 2005

My 2002 Yukon XL 8100 has it and the dealership says its "Normal". It only does it when the engine is cold, and is fine once it warms up. It sounds horrible, and it can't be good for the engine. Anyone else had this problem, and what have you done about it? I have 60K on it, and I have an extended warranty, but if it's "normal" the warranty won't cover it.
What do you think.

I found a website at pistonslap dot com, check it out sometime.

Kevin

<{POST_SNAPBACK}>

It is normal, only because it happens to many of them. The good news is that it doesn't seem to bother long term durability. My dad has an 02 4.8 in his Silverado and it has done it for 3 years. It doesn't bother performance and the thing runs great. Fuel economy hasn't changed, either.

I have a friend who was a GM service manager and he's seen many with 100,000+ miles with no problems other than it being annoying. Many of those did much heavy towing, too. He said it wasn't piston slap, though. He said it was carbon build-up due to the piston/ring design. They cleaned my dad's a couple of times and cured it for about 5000 miles, but he just decided to leave it alone.

I had a 99 Silverado Z-71 5.3 that had 120,000 miles on it when I sold it. It now has about 130,000 on it and it just started doing it. I was on the throttle hard all the time and ran fuel system cleaner through it every 6k miles. The new owner drives short trips and is easy on the throttle. Other than that, the thing still turns in the same fuel economy and runs great when warmed up. Original spark plugs, belts, and hoses, too. That was a great truck. I'm starting to miss it!

Of course, I'm assuming you are having the same issue. It could be something completely different from my experience.

the mouse · December 16, 2005

My 2002 Yukon XL 8100 has it and the dealership says its "Normal". It only does it when the engine is cold, and is fine once it warms up. It sounds horrible, and it can't be good for the engine. Anyone else had this problem, and what have you done about it? I have 60K on it, and I have an extended warranty, but if it's "normal" the warranty won't cover it.
What do you think.

I found a website at pistonslap dot com, check it out sometime.

Kevin

<{POST_SNAPBACK}>

It is normal, only because it happens to many of them. The good news is that it doesn't seem to bother long term durability. My dad has an 02 4.8 in his Silverado and it has done it for 3 years. It doesn't bother performance and the thing runs great. Fuel economy hasn't changed, either.

I have a friend who was a GM service manager and he's seen many with 100,000+ miles with no problems other than it being annoying. Many of those did much heavy towing, too. He said it wasn't piston slap, though. He said it was carbon build-up due to the piston/ring design. They cleaned my dad's a couple of times and cured it for about 5000 miles, but he just decided to leave it alone.

I had a 99 Silverado Z-71 5.3 that had 120,000 miles on it when I sold it. It now has about 130,000 on it and it just started doing it. I was on the throttle hard all the time and ran fuel system cleaner through it every 6k miles. The new owner drives short trips and is easy on the throttle. Other than that, the thing still turns in the same fuel economy and runs great when warmed up. Original spark plugs, belts, and hoses, too. That was a great truck. I'm starting to miss it!

Of course, I'm assuming you are having the same issue. It could be something completely different from my experience.

<{POST_SNAPBACK}>

The problem is between the piston pin and piston. The clearance between the two is .00025 or less. Any varnish from oil breaking down would reduce this clearance further. A engine flush (Amsoil makes a great one) would clear this out, and reduce or eliminate the problem.