Piston Slap? Or something worse?
Thread Starter
Instructor
Joined: Oct 2022
Posts: 213
Likes: 58
Piston Slap? Or something worse?
I have always heard this sound to some degree since I bought the car last August, though I had it up on jackstands today to do an oil change, and when I got under the car, it was too loud to ignore.
The car was definitely cold in this video, haven’t been started in a day or so and it did quiet down a bit after a minute or two, but I could still hear it slightly.
This video is under the car just beneath the front of the engine and belt assembly.
let me know your thoughts.
The car was definitely cold in this video, haven’t been started in a day or so and it did quiet down a bit after a minute or two, but I could still hear it slightly.
This video is under the car just beneath the front of the engine and belt assembly.
let me know your thoughts.
Burning Brakes
Joined: Jun 2022
Posts: 758
Likes: 366
Mine definitely has it and sounds like that. It should speed up with rpm’s
I might say that it’s a little higher pitched than what I’m used to but my hearing sucks and I’m not in person.
The sound should go away after the car is warmed up.
I had a 4.8 Silverado farm truck that made that sound for 200k miles ( started with a 100k) and never had an issue.
I might say that it’s a little higher pitched than what I’m used to but my hearing sucks and I’m not in person.
The sound should go away after the car is warmed up.
I had a 4.8 Silverado farm truck that made that sound for 200k miles ( started with a 100k) and never had an issue.
Thread Starter
Instructor
Joined: Oct 2022
Posts: 213
Likes: 58
Mine definitely has it and sounds like that. It should speed up with rpm’s
I might say that it’s a little higher pitched than what I’m used to but my hearing sucks and I’m not in person.
The sound should go away after the car is warmed up.
I had a 4.8 Silverado farm truck that made that sound for 200k miles ( started with a 100k) and never had an issue.
I might say that it’s a little higher pitched than what I’m used to but my hearing sucks and I’m not in person.
The sound should go away after the car is warmed up.
I had a 4.8 Silverado farm truck that made that sound for 200k miles ( started with a 100k) and never had an issue.
Burning Brakes
Joined: Jun 2018
Posts: 756
Likes: 172
From: SC
Sounds just like mine when not warmed up. I can hear it much more outside the car at idol vs inside rolled up. But yep as I drive off, higher revs make it clear inside rolled up. Sometimes it's hard to let go as piston slap, I grew up with noises like that being valve tap or rods...but everyone says piston slap. I wish there was an additive to quiet it before warm up. It bothers me because it sounds broke. Ya know.
Burning Brakes
Joined: Jun 2018
Posts: 756
Likes: 172
From: SC
Race Director
Joined: Aug 1999
Posts: 11,126
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From: SE Pennsylvania
St. Jude Donor '03 thru '26
Oldtimer
Most if not all LS1 have 'piston-slap' and both of my 03's had/have it, it is not a dangerous. I'm not too sure you have piston-slap. mine is a very deep internal sound, more internal than a rocker out of adjustment. My car has it once started cold, but by the time I back out of my driveway, and have gone 2 blocks and or the temperature rises over 100 degrees. 1 mile down the road it is gone.
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Michael S. Palmer
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I do know that at one point in time GM was replacing engines if the slap was bad enough. Never happen now, 20 years down the road. If it goes away after a couple 3 minutes, I wouldn't worry about it. Even though mine sounded bad in cold weather, it never used much oil, maybe 1qt every 4,000 miles, when I'd change oil. The totally stock motor was healthy enough to take my car to a 12.50@114mph 1/4 mile....
Intermediate
Joined: Oct 2021
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My 2000 Silverado 4.8 has done that for over a decade, with no apparent ill effects. I just let it warm up a bit, especially in winter (it sounds pretty bad starting in the middle of January). The Vette doesn't do it (also MY2000), but it has 1/3 the mileage and I never start it when cold out.
Racer
Joined: Oct 2021
Posts: 324
Likes: 157
From: Maine
I have the same sound and I can hear it going down the road until the oil get to 100-120 degrees. The sound bugs the crap out of me until its warms up so I turn up the stereo, then it's all better.
Last edited by JCMDoug; Apr 10, 2023 at 06:44 AM.
Race Director
Joined: Oct 2004
Posts: 12,864
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My 2000 Silverado 4.8 has done that for over a decade, with no apparent ill effects. I just let it warm up a bit, especially in winter (it sounds pretty bad starting in the middle of January). The Vette doesn't do it (also MY2000), but it has 1/3 the mileage and I never start it when cold out.
Thread Starter
Instructor
Joined: Oct 2022
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Thanks everyone. You put my mind to ease! I also now realize that the car is lifted up, has the wheels off, and is idling in my garage.
That’s probably the perfect recipe to make that piston slap as loud as it’s ever been to my ears. It’s like and echo chamber in the garage.
That’s probably the perfect recipe to make that piston slap as loud as it’s ever been to my ears. It’s like and echo chamber in the garage.
Burning Brakes
Joined: Jun 2018
Posts: 756
Likes: 172
From: SC
Thanks everyone. You put my mind to ease! I also now realize that the car is lifted up, has the wheels off, and is idling in my garage.
That’s probably the perfect recipe to make that piston slap as loud as it’s ever been to my ears. It’s like and echo chamber in the garage.
That’s probably the perfect recipe to make that piston slap as loud as it’s ever been to my ears. It’s like and echo chamber in the garage.
Burning Brakes
Joined: Jun 2022
Posts: 758
Likes: 366
Thanks everyone. You put my mind to ease! I also now realize that the car is lifted up, has the wheels off, and is idling in my garage.
That’s probably the perfect recipe to make that piston slap as loud as it’s ever been to my ears. It’s like and echo chamber in the garage.
That’s probably the perfect recipe to make that piston slap as loud as it’s ever been to my ears. It’s like and echo chamber in the garage.
It’s not a pleasant sound but it does go away. Like I said I just start mine and walk away for a bit when it’s colder outside