Weird Tapping noise @ 3500 RPM under decent acceleration

[jojo506082]

Fellas,

I have a black '07 z06 with about 39200 miles on it. I've had a string of problems lately starting with a a/c compressor failure, a water pump leak, and now I've been hearing a tapping noise coming from the engine at 3500 rpm in third or fourth gear under pretty decent acceleration. I don't track the car and only take the it to the dealer for mx.

I have GMPP major guard with no deductible that I've decided I'm going to extend (it expires on 11 Feb). So I haven't needed to pay for any of these problems.

Problem is I took it to the dealer to investigate the latest tapping noise and they found an oil leak in the cooler line, which they've fixed. They thought that would solve the tapping problem but it's still happening. The dealer advised me that the tapping is so hard to hear and only at a very small range of engine operation that they can't pinpoint it. The service dude thought it might be a problem in the #2 cylinder. If I have them tear apart the engine and they can't find the source of the problem I'll be on the hook for the engine tear down and rebuild (approx $900) because they can't bill GMPP without an actual problem. The service dude said hes worried that they won't find anything, that it could be a piece of carbon build up making that noise. He explained that if I take the car back it will not void the warranty--and if the noise gets louder just take it back in and theyll take care of it.

Any thoughts?

Thanks

[lar66bb]

Did they check the heads for valve guide wear?
Lot of info on the other forum in the Z06 section.

[dcsteg]

Originally Posted by lar66bb

Did they check the heads for valve guide wear?
Lot of info on the other forum in the Z06 section.

Valve guide. Improper machining as pointed out in service bulletin. GM finally admitted there is a problem. Check with them. I think your year is mentioned. They advise bringing it in before engine failure. I am surprised the SD didn't catch this.

Continue to run it if they ignore you. The tapping should get worse and then engine failure for sure. New Engine on them.

[jojo506082]

Thanks for the replies guys. I have the write up back at my house, I'm out of town this weekend so I can't look at it. But I think it said something about checking the valves for a triangle stamped on them?? I can't remember if it was the rocker arms or valves now that I'm out here. When I get home I'll grab the write up and post it on here.

Anyway, I saw the valve guide post which said:
LS7 Valve guide issue summary:
• Affects a small, number of '08, 09 ’10 and ’11 Z06’s...

Did '07s get added to this list? From what I understand its common knowledge (tech bulletin??) that '07s can have a rocker arm issue.

[dcsteg]

Originally Posted by jojo506082

Thanks for the replies guys. I have the write up back at my house, I'm out of town this weekend so I can't look at it. But I think it said something about checking the valves for a triangle stamped on them?? I can't remember if it was the rocker arms or valves now that I'm out here. When I get home I'll grab the write up and post it on here.

Anyway, I saw the valve guide post which said:
LS7 Valve guide issue summary:
• Affects a small, number of '08, 09 ’10 and ’11 Z06’s...

Did '07s get added to this list? From what I understand its common knowledge (tech bulletin??) that '07s can have a rocker arm issue.

I could be incorrect that 07's were included in the list. Better check it out.

[jojo506082]

I got their write up, they're thinking possible cylinder 2 rod bearing worn. They removed the valve covers and checked valve springs, rocker arms, and push rods... they checked for a stamped triangle on the rocker arms, which mine did not have... so they're good. Anyone have a rod bearing wear out and know what it sounds like?


Anyone know if an oil analysis would do any good?

[PG45]

My 08 only has 4500 miles and is tapping at 3500 rpm looks like im going to have to bring it to the dealer to check this out. I thought it was detonation from bad gas.

[jojo506082]

Hey PG45, did you ever take it in and figure it out??

I'm in the middle of a move and haven't had time to post on the forum. But I took the car back from the dealer and the noise stopped after driving it for awhile, so maybe it was a piece of carbon??

[PG45]

Originally Posted by jojo506082

Hey PG45, did you ever take it in and figure it out??

I'm in the middle of a move and haven't had time to post on the forum. But I took the car back from the dealer and the noise stopped after driving it for awhile, so maybe it was a piece of carbon??

Thats funny...same thing happened to me. Sent it to the dealer, they could not replicate the noise and its hasnt come back. They were thinking "bad" gas.

[jub jub]

I wouldn't lose any sleep over it. Check out this thread. More common than you think.

Poll: Does your 02 or newer engine tick?

[jojo506082]

well I guess we're in the clear