[Stuckinda60s]

I've got 105K on my 2000 GMC with the 4800. In the last year or so, it's developed a rap when first started with it much more pronounced in cold weather. In warm weather it might or might not do it. I know they have issues with piston slap but this sounds more like a single, loud, lifter clack. It clears up within 15-20 seconds.

What I'm thinking is that the oil may be draining back and it takes that length of time to fill the system and I get the clack until it does. The oil pressure comes right up on the gauge, but that doesn't mean everything's pressurized.

It's not impossible that it's piston slap, but it does clear up more quickly than the engine warms up and has a higher frequency than what I'm used to with slap.

I haven't listened to the piston-slap issue but I know a lot of engines developed very quickly after they were put into service.

Anyone got any experience or expertise in this area?

Thanks, Rich

[Stuckinda60s]

Anyone??

Rich

[Larry P]

Its piston slap all of the trucks have been doing this for a while now my 2000 Tahoe has 150k and does it for a min or so cold. The pistons have very short skirts in these and with tube style headers it really makes some noise at first start. I have seen no oiling poblems or any problems with the piston slap. GM was going good for 100k on the motors when the problem first started . The Chevy dealer I work for sells over 500 trucks a year and were not having any issues other than the noise.

[Stuckinda60s]

Thanks, Larry!

I really didn't think there was any major problem with it. Just wanted to double check and see if there were any oiling issues. It doesn't even last for a half-minute and is only apparent in cold weather. I imagine it will be somewhat noticeable in the warmer weather as it's louder, now, than it has been in the past.

One concern was that I may get a new one and I'm debating whether to sell it outright or trade. If I sell it outright I don't want to tell potential buyers it's a good vehicle despite the noise. And, if they don't hear it because the weather's warmer, I still want to give them a heads-up

Thanks, again, Rich

[Jerry H.]

Just FYI, I was a sales manager at a GMC store from 2000-2003. A lot of those trucks made that noise when BRAND NEW! Especially the 4.8 trucks. I remember cranking one that had been sitting a couple of months without being moved and thought it was a diesel! But as has been posted, I don't think their has been any real problem from this. My 6.0 in my 01 Yukon Denali does it with 60k miles. It seems as they had the problem under control by 2004, as my 04 Sierra 5.3 doesn't seem to have this problem. I wouldn't give it a second thought.

[Stuckinda60s]

Thanks again, guys! I guess I've been lucky that it hasn't been noticeable before now. Correct me if I'm wrong, but doesn't carbon contribute to the noise? I've heard of the noise diminishing or disappearing after a dose of Top Engine Cleaner. Anyone else heard of that?

Rich

[trailwing]

What they said. My buddies worked at a GM dealer at the turn of the century. They rebuilt/replaced several motors around 2000 and finally quit doing anything about it. Doesnt seem to hurt anything. My 2004 doesn't do it, so I think they figured it out by then.

[Stuckinda60s]

I still have the truck, 135K on it, now. I bought a new '08 Sierra with the 5.3 and decided to keep the old truck when they would only give me $2K for it.

I used a good dose of Red Line Fuel Treatment on it and the noise cleared up, for a while. I started a thread about it. It appears that there''s a problem with carbon in the clearance volume which contributes to the noise. The noise came back within a couple of months.

[poncho-mike]

My son has a 2000 GMC with the 5.3, and it's had what I thought was piston slap since he got it with around 140K. As it now approaches 300K on the bottom end, it hasn't caused any issues yet. He recently rebuilt the top end, but the bottom end was untouched. It certainly hasn't hurt the longevity of the motor.

[FrankieT/A]

I had 2001 suburban with 6.0 that thing was noisy upon start up (piston slap) got quieter upon warm up. The X got it in the divorce when it had 140,000 4 years ago. Her brother has it now so I don't what's going with it. But, I never had any issues with it.
I presently have a 2001 with a 4.8. It has 234,000 on it never had it apart. Runs perfect and is fast as shti. Ive never done anything to it. It still has original spark plugs. I do change the oil though. I flog the hell out of it. it gets a lot of WOT blasts. Because of how fast it is I haven't had the heart to sell it. I have a new Denali with a 6.2 and have no noise or issues.

[mechanic17]

I call the 10-30 second startup noises the "Ford Death Rattle" because every SB Ford I've owned did it. The oil pump pickup tube is so long (pump in front, pickup 10 or 12 inches back) that it takes several seconds to prime.

My Kawasaki Vulcan did it, too.

My 2009 5.3l GMC will make a little lifter noise in extreme cold.

In every case, Lucas Oil Stabilizer quieted or fixed the problem, except for the Fords that were already too far gone to help.

[Formulabruce]

GM added more nickle to the newer truck pistons and bores to help prevent this