# new M06 gto motor is knocking



## KC.MO.GTO (Jul 7, 2006)

I just bought my 06 gto with 63 miles and noticed knocking from the motor and a clunk from trans or rear end. What the heck I traded my 01 2500Hd with the 8.1 piston slap vortec for an 06 6.0 ls2 rod knocker. I regret getting the diesel goat and just want my piston slappin truck back. And the dealer said this is no big deal and they cant get me in for almost two weeks and its ok to drive because theres nothin wrong and if there is it would just be an exhaust leak. Now I have 530 miles on it and noticed that the knocking can be heard from both front wheel wells and usually begins knocking about 30 seconds after start up. IF it was an exhaust leak both headers must leak and find this hard to believe. I bet somebody had there foot sar far in the motor it was sticking out the grill. Has anybody had such issues with there gto? OH ya forgot to mention the clunk that happens when i shift my 6 speed


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## Mike-Omologato-G. (May 13, 2006)

*.*

Check the front struts, if you have a Feb. '06 build, they're toast.
My car also kind of clunks into 5th.


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## Holden (Sep 10, 2005)

Sounds like buyers remorse, I hope it turns out OK. 
http://www.gtoforum.com/showthread.php?p=83406#post83406


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## onyx_z71 (Jun 29, 2006)

My new '05 has plenty of piston slap until it gets warmed up. While my Avalanche didn't start slapping until about 25,000 miles, and doesn't slap at all when outside temps are above 50F degrees, I was suprised that the GTO was slapping new, and on an 80F day. I wondered if premium fuel may help in the hopes that it is only a cold slight pre-ignition knock. I haven't put premium gas in it yet, and don't know what the dealer put in it when they filled it upon delivery. Car only has around 400 miles on it, so I'll give it a few thousand, try premium, and see if it gets any better.


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## MaximumPwr (Oct 13, 2005)

My 06 started making a knocking noise after I put in 87 octane. I put in 93 octane and it hasn't done it again. But for about a day I was freaking out.


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## Cadsbury (Dec 6, 2005)

GM Recommends premium fuel for our cars and the cost difference between regular and premium isn't enough for me to be concerned about. I've allways used premium and have never had a knock problem. A friend of mine uses regular and complains about knock all the time. Both are 05's with about 8000 miles on them...


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## onyx_z71 (Jun 29, 2006)

Yeah, at the next fill up, I'll try premium gas. Hopefully, that'll help. It's just a little hard for me to believe that it'll do the trick. I would think that spark knock would be more likely to happen when it's warmed up rather than cold, but variable computer controlled factors when it's cold probably play into the mesh with possibly more fuel being delivered when it's cold and causing it. I've got about a half tank to burn out before I try it. Shouldn't take too long.


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## KC.MO.GTO (Jul 7, 2006)

My gto does not have piston slap wich will begin knocking right after start up and quit when it gets up to operating temp. My gto knocks after motor starts getting warm and seems to become very noticeable at normal operating temp.
I have 92 octane here in Kansas City MO. and only fill my tank with that. I suspect my salesman filled up with 87 octane but he denies this when i asked him. So as far as i know only premium fuel has been used. I wonder if the dealer ran the crap out of my car during those 63 miles they put on it.
when i went to check out the gto the salesman takes me for a ride up to 100 miles per hour in an automatic and then let me have a go for it. Well his sales tactic worked now I own a manual. Ive been reading some other forums and people are talkin about how easy it is to downshift from 5 to 2 on accident causing the rods to bend slightly. ?? wonder if lead foot up at the dealer got the chace to make this nasty mistake in my car before i bought it?? Monday the car goes to the dealer. I almost bet money my car will still be ticking and they willl say this is normal. JUst like they did with the piston slap that i learned to live with in my truck. LOVE the car HATE the tick its embarrasing.


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## GTO JUDGE (May 14, 2005)

KC.MO.GTO said:


> My gto does not have piston slap wich will begin knocking right after start up and quit when it gets up to operating temp. My gto knocks after motor starts getting warm and seems to become very noticeable at normal operating temp.
> I have 92 octane here in Kansas City MO. and only fill my tank with that. I suspect my salesman filled up with 87 octane but he denies this when i asked him. So as far as i know only premium fuel has been used. I wonder if the dealer ran the crap out of my car during those 63 miles they put on it.
> when i went to check out the gto the salesman takes me for a ride up to 100 miles per hour in an automatic and then let me have a go for it. Well his sales tactic worked now I own a manual. Ive been reading some other forums and people are talkin about how easy it is to downshift from 5 to 2 on accident causing the rods to bend slightly. ?? wonder if lead foot up at the dealer got the chace to make this nasty mistake in my car before i bought it?? Monday the car goes to the dealer. I almost bet money my car will still be ticking and they willl say this is normal. JUst like they did with the piston slap that i learned to live with in my truck. LOVE the car HATE the tick its embarrasing.



*Sounds to me like the timing may off a little. If the timing is off and even if you use proper octane, you can still get knocking. *


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## KC.MO.GTO (Jul 7, 2006)

GTO judge said:


> *Sounds to me like the timing may off a little. If the timing is off and even if you use proper octane, you can still get knocking. *



If the timing is off a little will f things up if i keep drivin it?
I pray that they get me fixed up so i can get some sleep I am worried sick about this car


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## GTO JUDGE (May 14, 2005)

KC.MO.GTO said:


> If the timing is off a little will f things up if i keep drivin it?
> I pray that they get me fixed up so i can get some sleep I am worried sick about this car


*The timing not correct will not hurt anything, but the engine's performance will be diminished. Prolonged knocking will in time damage internal parts. If the knocking is as extreme as you describe, I would be leery on driving it. Octane ping is easily corrected by intalling a higher grade gas, but you already have done that and the problem persists. 

If the timing is "out" this may be the easy fix by tuning the engine, but until the car is tested you won't know for sure. 

I think I'd have the car at the dealer and not drive it until the problem is fixed. Better safe than sorry.*


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## KC.MO.GTO (Jul 7, 2006)

I will leave it in the garage until monday. When starting somtimes it seems to turn over more slowly than other times. I would think that you could be right about the timing


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## GNX231 (Dec 12, 2004)

first thing is salesmen are putting reg. gas into the goats when filling them up before you take it home that happened to a friend of mine who bought an 05 after i told him the car has a high comp. ratio and needs super he said "are you sure" right there i new this guy just does not care and was not a car guy. 

as for the knock you discribe if it's that bad and is infact a rod knock don't drive it you'll just end up throwing a rod. that said the injector pulse is very loud and could be mistaken for a knocking like sound a true rod knock can only be described if you have not ever heard one is like a little man inside the block with a hammer wacking away


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## KC.MO.GTO (Jul 7, 2006)

Mike-Omologato-G. said:


> Check the front struts, if you have a Feb. '06 build, they're toast.
> My car also kind of clunks into 5th.


MY car was built 02/06 no visible problems yet. When I first brought my car home there was oily junk dripping from driver side wheel well. Dealer said it was the undercoating getting hot and melting. This seemed kinda wierd that a new car would melt but it did quit drippng the next day or so. The black coating is still tacky though. Wonder how long before it dries or will it?


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## KC.MO.GTO (Jul 7, 2006)

GNX231 said:


> first thing is salesmen are putting reg. gas into the goats when filling them up before you take it home that happened to a friend of mine who bought an 05 after i told him the car has a high comp. ratio and needs super he said "are you sure" right there i new this guy just does not care and was not a car guy.
> 
> as for the knock you discribe if it's that bad and is infact a rod knock don't drive it you'll just end up throwing a rod. that said the injector pulse is very loud and could be mistaken for a knocking like sound a true rod knock can only be described if you have not ever heard one is like a little man inside the block with a hammer wacking away


It's like one single knock as apposed to multiuple knocking or clattering if that makes any sense


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## GTO_Mike (Jul 24, 2006)

*low octane*

I was reading through the manual today and the book said that if you use lower octane fuel you may hear a knocking from the motor. Also, how much do you drive it? I had to let mine sit a few weeks and it made what sounded to me like a freaking horrible knocking sound when I first started it up. Once oil pressure got up though it was fine and now I drive it everyday and it doesn't do it anymore.


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## sonofgasguy (Dec 18, 2006)

KC.MO.GTO said:


> It's like one single knock as apposed to multiuple knocking or clattering if that makes any sense


:agree with Mike G:
1. Your front struts are fried. Return to dealer.
2. You should use premium fuel.


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