Engine Knock?
Thread Starter
Instructor
Joined: Apr 2009
Posts: 100
Likes: 0
From: Lynchburg VA
Engine Knock?
So I just bought this C6 yesterday and I notice on my way home 'Check oil level!'. I pulled over and put some mobil 1 5-30w in. When I got home I checked everything out again to make sure everything was alright. I've come to notice a noise in the engine bay. The noise is faint at idle but when rev'd gets pretty loud. Its not the lifter tick either, it sounds much much much deeper and louder. You can't hear the noise while your inside.
http://www.youtube.com/watch?v=XQ7D5qjZHxk
Also, while driving I have noticed when the clutch is engaged, from 2.5k and up there is a loud knocking noise.
http://www.youtube.com/watch?v=Gzmc8wnytGU
Anyone have a clue? I know its hard to hear from the videos. The first video you can hear it more right at the end.
Also, at idle with everything on (lights) the battery gauge flickers down and up, and the lights inside try to shut out.
Everything was perfect when I bought it..
http://www.youtube.com/watch?v=XQ7D5qjZHxk
Also, while driving I have noticed when the clutch is engaged, from 2.5k and up there is a loud knocking noise.
http://www.youtube.com/watch?v=Gzmc8wnytGU
Anyone have a clue? I know its hard to hear from the videos. The first video you can hear it more right at the end.
Also, at idle with everything on (lights) the battery gauge flickers down and up, and the lights inside try to shut out.
Everything was perfect when I bought it..
Melting Slicks
Joined: Dec 2006
Posts: 2,887
Likes: 2
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St. Jude Donor '13
Its hard to tell from a 10 second and a 4 second video.
Film a longer video and it may help with the Forum suggestions on what it may be.
This noise came up after the Low Oil light came on?
Any mods?
Ben
Film a longer video and it may help with the Forum suggestions on what it may be.
This noise came up after the Low Oil light came on?
Any mods?
Ben
Melting Slicks
Joined: Oct 2008
Posts: 3,355
Likes: 11
From: Beverly Hills, MI
Educate us more on the history of the car (what you know). New/Used? Mods? Oil level when you purchased it? Purchased from a dealer or from an individual? I assume that you were under the hood with the engine running to look things over before you purchased it?
Thread Starter
Instructor
Joined: Apr 2009
Posts: 100
Likes: 0
From: Lynchburg VA
I'll try for some longer videos. Everything was checked and in good order when we left. Unfortunately this was picked up by my dad and he didn't check the oil level. Car still had oil on the dipstick and I didn't hear any noises when I first got it.
Used, 05 with 56k on it. Stock. Bought from a small dealer locally. Warranty covers 50% labor/parts.
Used, 05 with 56k on it. Stock. Bought from a small dealer locally. Warranty covers 50% labor/parts.
Burning Brakes
Joined: Nov 2005
Posts: 804
Likes: 3
From: San Francisco Ca.
You mentioned that you added some oil, but, not how much. Also, since it is a used car, do you know when the last oil change was done? Too many variables.
Personally, I would change the oil and see if that helps first. Hope that helps.
Personally, I would change the oil and see if that helps first. Hope that helps.
Safety Car
Joined: Jan 2007
Posts: 4,300
Likes: 6
From: San Antonio Texas
Run the vin thru any GM service dept, just for the heck of it. That will show service history while under warranty.
Then, ask someone to run a carfax on it. NOT HERE. Any reputable car dealer runs car faxes daily.
Do that oil change first.
Then, ask someone to run a carfax on it. NOT HERE. Any reputable car dealer runs car faxes daily.
Do that oil change first.
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Burning Brakes
Joined: Oct 2006
Posts: 874
Likes: 0
From: Campbell Ca
From that first video right at the 9sec mark, right when the engine is winding down, it sounded like a faint rod knock to me. But like everyone says, its har do to tell from a short video clip. But it did sound more like a knock than a tic. Hope its not.
Maybe do a long clip when running cold and hot?? Just a thought.
Maybe do a long clip when running cold and hot?? Just a thought.
Melting Slicks
Joined: Oct 2008
Posts: 3,355
Likes: 11
From: Beverly Hills, MI
Honestly I don't hear anything. Based on your discription, I'd say either rod knock or piston slap, or maybe even poor oil circulation or oil pressure. An easy test to run is to (when you're about ready to change your oil) add a 1/2 quart of STP oil treatment. You know... the thick stuff? If after a few minutes the knock goes away, then that is a definite clue. If it goes away, then probably rod knock or poor oil pressure/circulation. If the knock doesn't go away, then maybe piston slap? Also, if the sound goes away when the engine warms up, then I'd vote more towards piston slap. I don't know if this helps you, but I thought I'd make the suggestion.
Team Owner
Joined: Aug 2004
Posts: 22,437
Likes: 2
From: Hamburger Hill...MAY 69
St. Jude Donor '08
After listening a few times to 1..at different volumes ..I kind of agree with Rocket ...a bottom end ...noise ....as stated connecting rod ....
Hope I'm wrong ...
Hope I'm wrong ...
Le Mans Master
Joined: Dec 2005
Posts: 7,753
Likes: 210
From: North Western Connecticut
I'll try for some longer videos. Everything was checked and in good order when we left. Unfortunately this was picked up by my dad and he didn't check the oil level. Car still had oil on the dipstick and I didn't hear any noises when I first got it.
Used, 05 with 56k on it. Stock. Bought from a small dealer locally. Warranty covers 50% labor/parts.
Used, 05 with 56k on it. Stock. Bought from a small dealer locally. Warranty covers 50% labor/parts.
Le Mans Master
Joined: Mar 2009
Posts: 6,893
Likes: 1
St. Jude Donor '09-'10-'11
Thread Starter
Instructor
Joined: Apr 2009
Posts: 100
Likes: 0
From: Lynchburg VA
Going to try the oil change tomorrow. The noise is not apparent when cold (thick oil). I added 2 quarts when it was low. Theres oil burnt on the top of the dipstick but the oil level has kept up since I added it so its not leaking or burning.
If all else fails, how much is a rebuild?
Also, the car has full power (i think). I smell exhaust if i take it over a certain RPM so maybe its an exhaust leak. I'm going to play with it alittle.
If all else fails, how much is a rebuild?
Also, the car has full power (i think). I smell exhaust if i take it over a certain RPM so maybe its an exhaust leak. I'm going to play with it alittle.
Thread Starter
Instructor
Joined: Apr 2009
Posts: 100
Likes: 0
From: Lynchburg VA
can engine knock be ALOT louder when the engine is engaged? In the cabin, when the car is not engaged, I can't hear any type of knock.
but when the car is in gear, its insanely loud when past 2.5k rpm. Before that no sign at all.
but when the car is in gear, its insanely loud when past 2.5k rpm. Before that no sign at all.
Burning Brakes
Joined: Nov 2005
Posts: 804
Likes: 3
From: San Francisco Ca.
You added 2qt's of oil? That indicates to me that the previous owner did not take care of this car. I would take it back to the dealer that sold this car, explain what you found. I don't know if that will help you or not. The engine did not have enough oil in it to protect it.
Good luck.
Good luck.
Drifting
Joined: Feb 2008
Posts: 1,320
Likes: 20
From: New York and Florida
Yes, since the engine will be under load.