Low Compression on One Cylinder
02-15-2015, 09:48 AM
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Low Compression on One Cylinder
I bough a 2007 Audi A6 3.2L with 107,000 miles. Right after I bought it in October it started making a knocking noise. After doing some research, I thought it was the timing chain. After tearing the engine apart, I found that the tensioners were just replaced. I bought a timing kit and everything is in time.
There was oil all over in the galley and in the passenger side spark plug tubes. I replaced the valve cover gaskets, installed 6 new ignition coils, and plugs. Started it up and the engine was still knocking.
I did a compression test and cylinder 2 was at 100 psi. All the others cylinders were between 170 and 180. Did a wet test on cylinder 2 and it jumped to 200 psi.
This shows that it is something with the piston, cylinder wall, or rings. Does anyone have any experience with a situation like this?
The car is nice, but I have driven it less than 200 miles since October as it has been parked trying to find research and time to work on it. I am trying to decide if I should just sell it as is, running with the knock, or try to fix it.
Thank you for any advice you have!
There was oil all over in the galley and in the passenger side spark plug tubes. I replaced the valve cover gaskets, installed 6 new ignition coils, and plugs. Started it up and the engine was still knocking.
I did a compression test and cylinder 2 was at 100 psi. All the others cylinders were between 170 and 180. Did a wet test on cylinder 2 and it jumped to 200 psi.
This shows that it is something with the piston, cylinder wall, or rings. Does anyone have any experience with a situation like this?
The car is nice, but I have driven it less than 200 miles since October as it has been parked trying to find research and time to work on it. I am trying to decide if I should just sell it as is, running with the knock, or try to fix it.
Thank you for any advice you have!
08-19-2017, 12:24 AM
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LOSS OF COMPRESSION ON CYL2 A6/3.2 USMODEL
I bough a 2007 Audi A6 3.2L with 107,000 miles. Right after I bought it in October it started making a knocking noise. After doing some research, I thought it was the timing chain. After tearing the engine apart, I found that the tensioners were just replaced. I bought a timing kit and everything is in time.
There was oil all over in the galley and in the passenger side spark plug tubes. I replaced the valve cover gaskets, installed 6 new ignition coils, and plugs. Started it up and the engine was still knocking.
I did a compression test and cylinder 2 was at 100 psi. All the others cylinders were between 170 and 180. Did a wet test on cylinder 2 and it jumped to 200 psi.
This shows that it is something with the piston, cylinder wall, or rings. Does anyone have any experience with a situation like this?
The car is nice, but I have driven it less than 200 miles since October as it has been parked trying to find research and time to work on it. I am trying to decide if I should just sell it as is, running with the knock, or try to fix it.
Thank you for any advice you have!
There was oil all over in the galley and in the passenger side spark plug tubes. I replaced the valve cover gaskets, installed 6 new ignition coils, and plugs. Started it up and the engine was still knocking.
I did a compression test and cylinder 2 was at 100 psi. All the others cylinders were between 170 and 180. Did a wet test on cylinder 2 and it jumped to 200 psi.
This shows that it is something with the piston, cylinder wall, or rings. Does anyone have any experience with a situation like this?
The car is nice, but I have driven it less than 200 miles since October as it has been parked trying to find research and time to work on it. I am trying to decide if I should just sell it as is, running with the knock, or try to fix it.
Thank you for any advice you have!
Same loss of compression on cylinder 2.\
Garage inserted camera into the cylinder and took photos of inside surface - result- deep scoring and deposts on surfece.
Valsves still seal-no damage, Piston rings-maybe.
Opinion of garage is that a substantial foreign object has been innserted into cylinder. In my case, coincided with replacement of plugs. My theory is that the mechanic tried to insert european plug (diam thread 14mm) into the american sparkplug thread (17mm) so the whole pplug disappeared down the cylinder! In any case, it wasnt me that dropped something in the engine!
I think Audi has to be challenged -
Why cylinder 2? Well, follwoing the manual cylinder 2 is the furthest to the front of the engine and is the first to be accessed by mechanic during a plug change.
How to be sure what happened?? I would say analyse the sump oil for enamel 9PLUG STEM) and analyse the film on the cylinder.
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