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Discussion Starter · #1 ·
Hey Everyone,
I'm sure this has discussed many times before, has anyone here had any luck quieting down "The Slap"... Piston Slap by switching to a different weight oil I.E 10-30W..? was just curious....My 02 Coupe is so loud in the morning its embarrassing....it still does after i have driven the car for a while and let it sit for 10 mins or so...Any help here would be appreciated ! :drunken:
 

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Are you sure it's not the tranny making noise when in neutral?

My 02 Z06 has some cold piston slap noise for about the first 3 minutes after a cold startup, but then quiets down pretty good. Running Mobil 1 5w-30 oil.

Try pushing in the clutch to see if the noise changes or not. Otherwise, trying 10w-30 might help ... I've been thinking of running 10w-30 on the next oil change.
 

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I ran M1 10W-30 in my '02 Trans Am. It didn't change the piston slap issue at all. Mine starts out quiet, but after 10 seconds or so it starts to make noise. It gets louder and louder.

So far the '04 Z06 doesn't have this problem.
 

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Oh No !! I've got "The Slap!" Don't worry about it, it's normal. As long as it goes away shortly after start up. If you want quite buy a Lexus. :cheers:

.
 

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Hows Buying a Lexus going to make his Z06s Slap go away, :lol: :lol: :lol: , maybe blasting the stereo right when he starts it will :D
 

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Try a bottle of Pro-Long engine additive, I'm not guaranteeing it will work but one of my buddy's had an LS1 in his high boy roadster and it had some piston slap, he was going to be selling the high boy at the Fathers Day Roadster Swap Meet and put the Pro-Long in it a month or so before he sold it even though he was already using Castro Synthetic oil, the engine slap did however go away until the time he sold last June. He instructed the guy that bought it that he had been using Castor with the Pro-Long additive and I still see the car at Hot Rod runs in So Cal and the guy has never complained to him about any more piston slap to his so i'm assumining it must have helped.
I'm not one to beleive in miracles in a can but for the price of a bottle of Pro-Long I would give it a try. GOOD LUCK
 

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If the sound you are hearing is a hollow knocking scraping sound that goes away sometimes and is more pronounced in the morning and after the car sits, check the idler pulley bolt to see if it is loose or the bearing is worn out. My 01 had this sound at 13,000 miles and that is all it was. No noise at start up anymore cold or not, no "piston-slap". To determine this I started the engine cold with no belt and the noise was gone. ;)

The bolt may feel tight, it has lock tight on the threads. I also replaced the idler because they are cheap enough and most auto parts stores have them. While I was at it, I replaced the belt.

Hope you track the noise down this is sometimes hard to do.

Good Luck.
 

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02VETTECOUPE said:
Hey Everyone,
I'm sure this has discussed many times before, has anyone here had any luck quieting down "The Slap"... Piston Slap by switching to a different weight oil I.E 10-30W..? was just curious....My 02 Coupe is so loud in the morning its embarrassing....it still does after i have driven the car for a while and let it sit for 10 mins or so...Any help here would be appreciated ! :drunken:
I had the slap when I was using Mobil 1 and it was quite loud . I switched to Amsoil series 2000 and the slap has quieted down quite a bit . It is not gone but unless you are under the vette right after you start it you cant hear a thing. I have not heard of anyone else that this worked for it is just what happened for me after the change
:cheers: :cheers:
 

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Took the Trans Am to the dealer today for piston slap. They do agree that is the noise I hear. They carbonized the engine. I don't think this will help the problem, but I will let you guy know. Do I need to change the oil know?
 

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The piston slap problem seems to be with the 01-02 cars....

My 01 firehawk had it really really bad from the factory and I added a heads and cam package and the car ate a quart of oil every 1000 miles and just got worse.....then I added a supercharger and it toasted the rings.....good tuning too....the motor was dog crap from the factory and I gave it an early grave at 16,000 miles....

My 03 z06 doesn't make a peep at all cold, using 5w30 mobil one oil, doesn't burn any oil at all...motor has 2200 miles on it, so far so good, I'm going to switch over to redline 5w30 next oil change.....if the slap is really bad I would take it up w/the dealer, I've heard of some places replacing motors.....because of this slap and oil comsumption problems
 

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Discussion Starter · #13 ·
WELL... ITS AT THE DEALER TODAY....I'VE HAD THE DE-CARBON PROCESS DONE BEFORE.....THAT DIDNT DO ANYTHING... CURIOUS TO SEE WHAT THE DEALER SAYS AFTER HE HEARS IT..WHEN STARTED COLD..THE ENGINE IS QUIET FOR THE FIRST MINUTE OR TWO ,THEN IT STARTS "KNOCKING" AFTER THE HI-IDLE KICKS DOWN, AND IT WONT STOP EVEN AFTER ITS WARM....BUT IF YOU GIVE IT GAS..ITS GOES AWAY FOR A FEW SECONDS...THEN ONCE THE IDLE COMES BACK DOWN...THE KNOCKING STARTS AGAIN...EVEN WHEN ITS WARMED UP...ITS HARD TO PINPOINT WHERE THE NOISE IS COMMING FROM....ITS SEEMS TO BE THE LOUDEST ON THE PASSENGER SIDE...IT'S LOUD ENOUGH THAT MY NEIGHBOR FROM ACCROSS THE STREET HAS WALKED OVER AND SAID " HEY, WHATS UP WITH YOUR CAR.?" IS IT SUPPOSE TO SOUND LIKE THAT ..??? :screwy:
 

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02VETTECOUPE said:
WHEN STARTED COLD..THE ENGINE IS QUIET FOR THE FIRST MINUTE OR TWO ,THEN IT STARTS "KNOCKING" AFTER THE HI-IDLE KICKS DOWN, AND IT WONT STOP EVEN AFTER ITS WARM....BUT IF YOU GIVE IT GAS..ITS GOES AWAY FOR A FEW SECONDS...THEN ONCE THE IDLE COMES BACK DOWN...THE KNOCKING STARTS AGAIN...EVEN WHEN ITS WARMED UP...ITS HARD TO PINPOINT WHERE THE NOISE IS COMMING FROM....ITS SEEMS TO BE THE LOUDEST ON THE PASSENGER SIDE...
And it's done this since day one? If not, maybe there is a mechanical problem starting to surface. Maybe a bad lifter or rocker arm with a few needle bearings missing or maybe a flat spot on the rocker's roller.

Let us know what the dealer finds.
 

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Discussion Starter · #15 ·
UPDATE:
Well, its been in the shop for 7 days now. They can hear the "slapping" noise but can't pinpoint where its comming from.
heres the short version of whats its doing.
Turn the key and start it...as soon as the "high idle" starts to kick down (about 30 seconds) the knocking sound starts....i've timmed it before....if you dont give it any gas ...its goes as long as 12mins before i gave up and gave it gas to make the sound quiet down.....heres the bad part...it dosnt go away when warm....i'll drive the car for 20-30 mins and its still there. (Sounds just like rod knock) ....you can really hear it when you pull into a garage or a Drive-thru or somewhere where you can hear the sound "bouncing" off a wall or another car while sitting in traffic....any ideas here folks.???
The service manager called me back today and told me they are "99%" sure this is "normal"....but are going to contact GM to see if there are any TSB's about this...everyone at the dealer has heard how bad this engine sounds...i asked him.." How am i ever going to be able to sell this car someday..?? Who would buy it..??......any idea how i can get a GM area rep to come in and hear this..??
Thanks again, Sorry about the "Novel"...just venting here
 

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This sound like piston slap, but piston slap always goes away after a few minutes or so.
I've used Mobile 5w-30w and did not hear any slap. over the summer i switch over to Royal Purple, it ran great until winter/fall set in and then i got the slap. I changed over to Amsoil SAE 10W-40 Synthetic High Performance Motor Oil, nor more slap...
 

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I've been told the Amsoil Series 2000 Synthetic 0W-30 Motor Oil
is a great oil with lots of anti-wear agents.
 

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Turn the key and start it...as soon as the "high idle" starts to kick down (about 30 seconds) the knocking sound starts....i've timmed it before....if you dont give it any gas ...its goes as long as 12mins before i gave up and gave it gas to make the sound quiet down.....heres the bad part...it dosnt go away when warm....i'll drive the car for 20-30 mins and its still there.
Hmmm, difficult to say if that's piston slap or not. The fact that it doesn't go away when warmed up is what has me thinking it may not be piston slap in your case.

My '02 has a classic case of piston slap, and everything is as you described, EXCEPT the noise goes away once the engine is warmed up (about 3-5 minutes after startup, with oil temps about 140F and higher, its quiet).
 

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IMO I would rather put up with piston slap then run prolong in any motor.

http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=11;t=000113


RoHo said:
Try a bottle of Pro-Long engine additive, I'm not guaranteeing it will work but one of my buddy's had an LS1 in his high boy roadster and it had some piston slap, he was going to be selling the high boy at the Fathers Day Roadster Swap Meet and put the Pro-Long in it a month or so before he sold it even though he was already using Castro Synthetic oil, the engine slap did however go away until the time he sold last June. He instructed the guy that bought it that he had been using Castor with the Pro-Long additive and I still see the car at Hot Rod runs in So Cal and the guy has never complained to him about any more piston slap to his so i'm assumining it must have helped.
I'm not one to beleive in miracles in a can but for the price of a bottle of Pro-Long I would give it a try. GOOD LUCK
 

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Z06ified said:
Hmmm, difficult to say if that's piston slap or not. The fact that it doesn't go away when warmed up is what has me thinking it may not be piston slap in your case.

My '02 has a classic case of piston slap, and everything is as you described, EXCEPT the noise goes away once the engine is warmed up (about 3-5 minutes after startup, with oil temps about 140F and higher, its quiet).
Mine does what Z06ified's does ... makes some cold piston slap noise when first started, but goes away after 3~5 min of idling. Actually, for the first 30 seconds after it starts, the engine is very quiet ... then the piston slap feathers in and stays for 3~5 min then feathers out. Stays pretty quiet after warm-up.

I'd sure make the dealer check it out as much as possible. Might even be a good idea to have them remove the valve covers and checkout the valve train. Could be a mechanical problem with a rocker arm or roller.
 
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