Kevs50th

I have an '03 C5 A4 with just less than 11,000 miles. Last year right before I put her away for storage I started to notice a strange "tapping" sound coming from the engine after initially starting the car.

Last week I pulled my Vette out of storage and sure enough this "tapping" sound on initial start when the engine is cold is still there. Does this sound normal?

Please note: I have noticed that the "tapping" sound tends to decrease to the point of not concerning me as much after driving the car for a short while, getting out and listening.

Appreciate any feedback... I am concerned about this and thinking it may warrant a trip to the dealership (I have the GMPP).

GRUNIE

Here we go guy's. The infamous piston slap. Don't worry about it. My car does it too. Just let warm up before getting on it. The way I see it is, if the motor can survive the rigors of dyno testing, the piston slap is a moot point. Though I do hate that damn ticking on cold starts.

dgrant3830

Could also be a lifter going bad but I highly doubt it on an engine with only 11K miles. Depends on the tapping sound itself. Sound coming from higher up in the engine then lifters, down lower, piston slap. I lost a lifter but it was way up there in mileage.... a long ways up there, which doesn't mean you couldn't have had one go bad. If its a lifter, it will tap for a few starting up when cold then go away quickly. It will progressively get worse and take longer to go away. Finally, it will not go away till the engine starts to litterally warm up and at the end, it will start tapping loudy. Don't let it go past that point if this all happens.

jcerra

Nothing to worry about.

RFJohnston

yup I vote for piston slap..

RatedX

I have the same thing....Putting in a high flow oil filter helped a little, but it never really goes away. I hate it!

VinnyT

Yup, piston slap. I had a 98Z28 with LS1 that did it. Drove me crazy. Trust me, it was a LOT louder in the Z28 than ours.

Kevs50th

I think the sound is more prevalent from the bottom of the engine not the top. Based on the above posts (thanks!!!) it sounds like this is somewhat "normal" (piston slap) and I should not bring it in for someone at the dealership to look at. Let me know otherwise.

Thanks Again!!!

Phanni

Just what is piston slap? Pardon my ignorance.

VinnyT

When the engine is cold, the pistons are smaller than when it warms up. Cold - contracts, Warm - expands. When the motor is cold the pistons will slap from side to side in the cylinder until it warms up, which expands the piston.

Ishams00vette

Same thing happened to my 2000 SS... not on my Vette though!!

dndrsn

Why doesn't all eight of them slap?

dano99vert

I have same noise goes away after warmed up, 99 with 20k miles, not worried about it, everybody says its normal

ptdrummer54

http://www.pistonslap.com/

0DinoZ

What makes you think that all eight aren't slapping?

Big-Red

Back in the day we would 'blue print and balance' the piston slap away.
But with the LSX engine having sleeves I don't think this can be done or can it?

Kevs50th

Thanks all for the info. I did call a local dealer today and they suggested I bring the Vette in so they can inspect for a potential issue. I'll need to leave it overnight so they can hear the "tapping" when started first thing in the a.m.

I told them I'll monitor the situation for the next month or so to see if it is a predictable issue (e.g., "tapping" sound always goes away after engine warms up) or if the issue gets worse.

Corvette Don

Interesting article

FactoryRaceCar

My car does not do it though.

JustinStrife

Mine does it too. I just make sure she's got plenty of oil, and warm her up before I get on her.