O2Form

There is noway a piston thats slaps could stop slapping, its either fitted too loose or its not. Now carbon could cause a knock that comes and goes and i'm betting that what most of you are hearing.

If i start mine 100 times it sounds EXACTLY the same every time. It has a sound of a diesel engine for about 5-10 mins then its silent. Thats normal piston noise in a LS1.

A loose slapping piston WILL NEVER BE QUIET.

00MaroonZ28

iTrader: (3)

the 5.3's are nutorious for piston slap on warm up. My silverado as well as many of my other friends have it as well. Just let it warm up before you hammer on it.

lemons12

iTrader: (71)

I do.. But I let her warm up by holding it steady at about 5,500 RPMs for around 10 minutes.. She likes it I think.


Does a bit on start up and goes away. Did on my old white TA too, exhaust was too loud to hear it though. Only one that hasnt was a black Z28 I bought to DD for a while.

pat-ls101

Decarboned? How much does the dealer usually charge?

Ape Man

I have bill from GM when mine had 55,000KM for "knocking when cold" and lots of oil build up on piston tops.

They put in a brand new long block.

Car has 314,000, motor obvy 55,000 less, but quiet as a mouse

slayerized6

iTrader: (12)

the piston slap on my car is faint and I only hear it on colds start ups during the winter months.

xTraViSx

i've had two different motors in my car. Each have had piston slap. I replaced the first motor at 122,000. It was a 00. It had piston slap. Bought the car with 111k and it had it then. Replaced that motor with a 59,000. It was a 99. When i put the newer motor in it didnt have piston slap. I was thrilled. After about 5-10k of usage i had piston slap again. This motor now has 99k. Still has piston slap. The motor has made 5 700 mile road trips without failure. The motors was also daily driven in between those trips. Piston slap starts after about 30sec. to a min. It continues untill the car is at normal operating temp. I can even feel it in the petal when im driving it between 100-200 degrees. I try to let it warm up to 110 before i start driving. I take it very easy untill its completely warm.

green28

iTrader: (8)

Same deal here as most others, 99 with 49k miles. Have owned it since it had 17k miles on it. Has piston slap on cold mornings until the car gets to normal operating temps and then it goes away.

nukeemall454

my 98 Trans Am had none, but my 02 SS slaps pretty good on start up but then clears up pretty good once its warmed up.

Swampfox357

My 99 has 117k on it and it only has this on cold morning until it warms up. Say below 40 degrees. Does not burn oil or have any power loss. I worried about it until I checked and found it was almost normal for these cars.

Camaro99SS

iTrader: (4)

My 99 was very noticeable on cold startup, even over dumped true duals I used to have. It could very easily be mistaken for a bad rod knock. It would quiet down after it was above ~150 degrees, and it never burned any oil over 4-5k oil change intervals until I sold it at 134k. As long as it goes away and doesn't burn oil, there's nothing to worry about. The Chrysler Hemi's are like this (it's barely audible on my Charger down to 10 degrees, but a friend's Jeep is as loud as my Camaro was) too as are a number of other engines in a fairly high state of tune.

Jason

Mr CHI

iTrader: (3)

I have it and when it's cold, as in 10-20's, it is B.A.D. I'm scared to start it because I think it's going to start shooting parts out of the manifold.

Even when I turn the key to prime the fuel pump it takes .5-1 second for the electrics to even kick on. But when it cranks it idles nice, then 10 seconds later it starts pli-plip-plipping until it hits ~180, then it's really faint.

That's only in winter though. Summer it doesn't happen as much.

tatersalad25

my 5.3 started slaping last december when it got like down in the 20's and never went away after that, it progressively got worse untill I had to overheat the engine by pinching off the upper radiator hose to get it to go away.... needless to say out with the 5.3 and in with the 6.0

blsnelling

iTrader: (4)

The 5.3 in my '01 Sierra had it. It would be gone though by the time I got to the end of my drive, 300'-400'. This LQ4 I just built has none. I'm using the original pistons with 85K miles. They are the later style with coated skirts and the LS2 rods. No knock at all.

robertbartsch

none here.

ask yourself this. Why did Government Motors go bankrupt? Labor unions demanded high wages and benefits, GM became less competitive and cut corners on stuff like testing motors before they are introduced into the market.

O2Form

My 02 Formula has it so bad you would swear its lifters. It starts up quiet for about 30 seconds then starts to click and clack so bad its insane, hot its quiet. I've heard others wiith the exact noise. I know gm replaced ALOT of 5.3 engines with the same noise. Most dealers thought it was lifters but after replacing the lifters the noise was still there. Turned out to be piston noise.

Even hot in my engine you can still hear it but it doesn't click, Its a steady knocking that blends into the engine noises.

3rdgen92maro

iTrader: (20)

Mine has it and its LOUD on a cold morning...makes the usual clanking and clunking awful sound until shes warmed up. Then its nice and quite.

hiltsy855

iTrader: (35)

Like most people my '02 has it on a cold start, then goes away after 2-3 minutes. I think part of the problem is the LS1 has pretty short piston skirts.

robertbartsch

I know the later models of LSx engines do not have the problem. Is this due to the fact they later units do not have short piston skirts?

I thought the ring groves and ring designs were changed too: right?

NBM99SS

iTrader: (33)

Mine has it. It doesn't hurt anything. I let it warm up for about 30 seconds and take off