[Z06] Engine knocking
Thread Starter
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Joined: Jun 2000
Posts: 66
Likes: 3
From: Camp Hill PA
Engine knocking
I've noticed that my 02 Z06, which has 400 miles on it, has an engine knock when the engine is cold. I don't hear it at idle but only when the car slowly begins to move forward (as I let the clutch pedal out) I hear the knocking. After I've driven 1-2 miles the knocking is gone.
My trans makes noises too but this is not that. It's coming from the engine when under load. It's not very loud but I have good hearing.
I know there was a piston slap noise prior to 02 that was supposed to have been fixed with teflon coated fitted pistons. I'm hoping this isn't that.
Any ideas what is going on inside this beast? I can't wait for it to be broken in.
thanks
My trans makes noises too but this is not that. It's coming from the engine when under load. It's not very loud but I have good hearing.
I know there was a piston slap noise prior to 02 that was supposed to have been fixed with teflon coated fitted pistons. I'm hoping this isn't that.
Any ideas what is going on inside this beast? I can't wait for it to be broken in.
thanks
Le Mans Master
Joined: Sep 2000
Posts: 5,027
Likes: 320
From: N. CA
Re: Engine knocking (jeclarke)
Mine also had a diesel knock when cold during the first 2000 miles. It would go away once warmed up. The knock was very noticeable at about 2000 rpms...just like a diesel engine :eek:
Well, after many runs to the redline and letting it do its thing, no more knock. May be some carbon in the cylinders that needed to get cleaned out. Some report that the decarbonization procedure will take care of the knock also.
Get it broken in and then really rev it up, or try the decarb.
Good luck.
:chevy
Well, after many runs to the redline and letting it do its thing, no more knock. May be some carbon in the cylinders that needed to get cleaned out. Some report that the decarbonization procedure will take care of the knock also.
Get it broken in and then really rev it up, or try the decarb.
Good luck.
:chevy
Le Mans Master
Joined: Jun 2000
Posts: 5,555
Likes: 9
From: Indiana
Re: Engine knocking (jeclarke)
With 400 miles, you don't need to worry about carbon buildup. Describing noises can be difficult. The tranny does make some noise on takeoff, as mentioned in the Z06 video. Also, the injectors tend to click under light loads in the 1500-2000 RPM range, as reported by numerous owners. If you're really hearing a 'knock' rather than a 'tick' it bears monitoring. I doubt that having someone at the dealership listen to it would do much good, but if you can find a similar car in your area, maybe another forum member, try to set up a meeting to do an A-B comparison with your car. A heavy knock can be indicative of bearing problems, but this really seems unlikely on a new car. How's your oil pressure? Best advice is not to worry about it too much. Drive the car and enjoy it ... if it breaks, you've got the warranty. Just my $.02.
Race Director
Joined: May 2000
Posts: 12,712
Likes: 2,270
Re: Engine knocking (Jerry Velders)
The sound that you describe could be "piston slap", but late in the '01 model year the skirt clearance was tightened up to reduce cold slap and a polymer coating was added to the skirt to help prevent scuffing with the tighter clearance.
You didn't mention the ambient temps you are experiencing at cold start, but really cold weather could cause some audible slap, I suppose, even with the new design.
Cold piston slap shouldn't cause any long term problems, but just run the car easy until it warmsup and goes away.
Duke
You didn't mention the ambient temps you are experiencing at cold start, but really cold weather could cause some audible slap, I suppose, even with the new design.
Cold piston slap shouldn't cause any long term problems, but just run the car easy until it warmsup and goes away.
Duke
Racer
Joined: Sep 2000
Posts: 333
Likes: 0
From: Cedar Rapids IA
Re: Engine knocking (BOBSZ06)
Mine also had a diesel knock when cold during the first 2000 miles. It would go away once warmed up. ...
Some report that the decarbonization procedure will take care of the knock also.
...
Some report that the decarbonization procedure will take care of the knock also.
...
What works for me is to add a can of BG 44K or 3000 Mile fuel system cleaner to a full tank of gas. Some chevy dealers sell it over the counter. :chevy
Thread Starter
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Joined: Jun 2000
Posts: 66
Likes: 3
From: Camp Hill PA
Re: Engine knocking (Jerry Velders)
Jerry,
You're right about trying to describe noises in email. But since we're limited to that for the moment, what do the injectors sound like and would this noise go away after driving 1-2 miles?
You're right about trying to describe noises in email. But since we're limited to that for the moment, what do the injectors sound like and would this noise go away after driving 1-2 miles?
