# knocking/tapping sound?



## GTOsarge (Oct 9, 2007)

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.


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## 05GTO (Oct 6, 2004)

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.


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## GTOsarge (Oct 9, 2007)

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.


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## GM4life (Mar 18, 2007)

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


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## GTOsarge (Oct 9, 2007)

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.


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## GTOsarge (Oct 9, 2007)

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.


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## GM4life (Mar 18, 2007)

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.


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## LOWET (Oct 21, 2007)

*engine noise*

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


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## GTOsarge (Oct 9, 2007)

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.


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## Red Bearded Goat (Mar 19, 2007)

GTOsarge said:


> 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!


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## NJG8GT (Nov 14, 2007)

*oil filter*

Yea, that doesn't sound right. I too use a k/n oil filter on my wife's '07 tahoe. It seems to be working fine. I don't change the goats oil, my dealership down the road, owned by so-called family, has a deal where you buy a new car from them they will change your oil for as long as u own the car. They even use mobil 1 and told me they would still change it every 3000 miles. I had goat for almost one full year and only have apprx. 850 miles.


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## LOWET (Oct 21, 2007)

*engine noise*



GTOsarge said:


> 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.




Let us know how you make out with it


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## GTOsarge (Oct 9, 2007)

Got the car back yesterday. They replaced the cam and lifters. I saw the old cam. It had chatter marks on one lobe. Looked like someone took a round file and went around the top of the lobe. Anyway all covered by warranty.
No scratches or dents. I nailed it a few times on the way home and it runs as advertised. Glad to have it back.


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## 6QTS11OZ (Mar 27, 2005)

GTOsarge said:


> Got the car back yesterday. They replaced the cam and lifters. I saw the old cam. It had chatter marks on one lobe. Looked like someone took a round file and went around the top of the lobe. Anyway all covered by warranty.
> No scratches or dents. I nailed it a few times on the way home and it runs as advertised. Glad to have it back.


Cool!


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## UdnUdnGTO (Jan 30, 2006)

GTOsarge said:


> 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.


OMG, that is new one on dealer/service manager psycho babble. I would love hear K&N view on that. Change the filter?? One of the highest rated filters is K&N. The medium is excellent and helps keep clean the longer drain intervals used by synthetic oils. Let me guess, they also recommended 3,000 oil change intervals, right?

Barbarians, that all they are preying on people that must defend themselves from such idioicy. 

Good luck.


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## PDQ GTO (Jun 21, 2007)

Red Bearded Goat said:


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


K&N oil filter causing the noise, I rather doubt it, very-very fishy. You would think the dealership could have come-up with something more plausible than that for an excuse. I use K&N, zero issues... :agree


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## 6.0goat (Sep 27, 2007)

*knocking or chattering*

Mine does this same thing. Between 1500 to 2000 rpm 25 to 45 mph in 4th, 5th or 6th. It drives me nuts. I suppose I'm going to have to make a trip to the dealer as bad as I hate to.


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## Rukee (Feb 8, 2007)

25mph in 4th 5th and 6th you`re lugging the motor, try down shifting.


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## GM4life (Mar 18, 2007)

Rukee said:


> 25mph in 4th 5th and 6th you`re lugging the motor, try down shifting.


CAGS might be getting the best of him.


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## 6.0goat (Sep 27, 2007)

gm4life said:


> CAGS might be getting the best of him.


What are CAGS?


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## GTO JUDGE (May 14, 2005)

Keep using the K&N filter. I have been using them since I purchased the car in 05'. I take my own oil and K&N to the dealer and they install it for me. 

I came across K&N's for like 4-5.00 a piece and purchased enough to get me to about 80K in oil changes. Starving the engine of oil? BOGUS.


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## GTO JUDGE (May 14, 2005)

6.0goat said:


> What are CAGS?


The Cags eliminates the 2nd gear lock out feature when shifting below 18-20mph.


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## GM4life (Mar 18, 2007)

6.0goat said:


> What are CAGS?


Computer Aided Gear Shift(or selection)AKA: Skip shift. It forces you to shift from 1st to 4th under light throttle condidtions under some circumstances. It was put there by GM on the T-56's to reduce emissions and to bypass the gas guzzer tax. It can be defeated by a risistor, programmer, tune or a $20 part called skip shift eliminator. Or you can rev your engine to about 3k and you wont see it.


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## mr.gto (Jul 2, 2008)

GTOsarge said:


> Got the car back yesterday. They replaced the cam and lifters. I saw the old cam. It had chatter marks on one lobe. Looked like someone took a round file and went around the top of the lobe. Anyway all covered by warranty.
> No scratches or dents. I nailed it a few times on the way home and it runs as advertised. Glad to have it back.



damn they must have hated to do that. According to book time..... replacing a camshaft in these cars takes 27 book hours!!! But im sure they beat that. Doubt ful they beat warrenty book time


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## GM4life (Mar 18, 2007)

mr.gto said:


> damn they must have hated to do that. According to book time..... replacing a camshaft in these cars takes 27 book hours!!! But im sure they beat that. Doubt ful they beat warrenty book time


I think the book calls for them to remove the engine.


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## mr.gto (Jul 2, 2008)

yea it also includes replacing the lifters. Im not sure exactly how they do it. Maybe they just pull the front off the car.


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