knocking/tapping sound?

GTOsarge · 11-11-2007, 01:45 PM

Hello all. I've had my 06 for about a month now. It has 10,500 miles. Noticed when I accelerate normally with the windows down I hear a light knocking/tapping sound at about 1500 rpm. At first I thought it was an exhaust leak. This happens when it's hot or cold. I don't have any performance issues. Runs great. Got home today and pulled it on the ramps
so I could pinpoint the noise. It's coming from the engine area underneath. I've heard about the LSX piston slap but this still goes on after the car is warmed up. As much as I hate to I'm thinking about takibg it to the dealer
to get it documented. Anyone suggestions would be appreciated.

05GTO · 11-11-2007, 02:12 PM

I had the same problem, turns out the A/C belt tensioner was bad. The service writer also thought it was coming from the valve train. It was covered under warranty.

GTOsarge · 11-12-2007, 02:01 PM

Took it in to the dealer this morning. Damn I hate it but what else could I do?
Waiting for an evaluation. It's not my daily driver so I told them to take their time and find out what it is.

gm4life · 11-12-2007, 07:16 PM

Keep us updated. Did the sound speed up when the engine rpm increased?

GTOsarge · 11-13-2007, 06:33 AM

Couldn't really hear it unitl 1500 rpm. It's not real bad but I thought it prudent to get it checked while warranty is still in effect.

GTOsarge · 11-13-2007, 12:53 PM

Update. When I changed the oil 4 hundred miles ago I used a K&N oil filter. My bad for not replacing it before taking it to the dealer for an engine knock.
When I talked to them this morning they asked about the filter and said that could be causing the problem. He said it could be starving the engine for oil???
Soooo.... they are going to change the filter and see If the noise goes away.

gm4life · 11-13-2007, 01:13 PM

Humm probly not, but hopfully its that simple, I can't remember on our engines but on the BB/SB engines you had a bypass valve that let oil bypass the filter it was small but it worked.

LOWET · 11-13-2007, 04:34 PM

once the LS2 motor is broken in [ your's is ] they are a little on the noisey side. Hearing a little lifter noise and other mechanical sounds are normal to hear at idle, but you should not hear it at 1500 RPMs or when driving it, Unless the owner before you put a cam in it. Get the oil changed because you don't know for sure what oil is in there now or HOW LONG it has been in there. Could be oil starvation if the level was too low or if the oil has broken down from long term use. OIL Change is a cheap way to know.

GOOD LUCK

GTOsarge · 11-14-2007, 05:57 AM

Thanks for the input folks. I changed the oil myself. Mobile 1. No cam. No low oil levels. I plugged my scanner in before I took it to the dealer. No codes.
I'll give them another week and see what they come up with.

Red Bearded Goat · 11-14-2007, 02:29 PM

Quote:

Originally Posted by GTOsarge

Update. When I changed the oil 4 hundred miles ago I used a K&N oil filter. My bad for not replacing it before taking it to the dealer for an engine knock.
When I talked to them this morning they asked about the filter and said that could be causing the problem. He said it could be starving the engine for oil???
Soooo.... they are going to change the filter and see If the noise goes away.

Lots of people use that K&N oil filter including myself and don't have a problem... sounds fishy... good luck!