Bad Valve Cover Gasket Change

[BlueBat]

I'm really stressed over a recent VC gasket change on an 00 LS V6 and could really appreciate some input on this topic.

While replacing the RH VC gasket a bolt broke off. I tried to remove the bolt with one of those Sears rethreading kits and ... the bolt-removing bit broke off too. Frustrated, I went ahead and replaced the VC with some gasket silicone and the remaining bolts. When I tried to start the car, there's a loud clanking noice I can pretty much assume is coming from that RH VC gasket. I'm not a big fan of the dealership mechanics since I have long history of bad experiences with them. Plus, I've done most all of the car's maintenance for several years and like to stay intimately familiar with all the parts.

Does anybody know just how much trouble I'm in here or have any suggestions? Before I take it to the dealership, I just want to get a good concensus.

[shorod]

Well, since I wasn't watching over your shoulder as you did the work, it will be very difficult for me to speculate on what may have happened. However, there are a few things to think about. When the bolt broke, I'm assuming you did not have the cover off yet, so no fragments of that bolt should be in the valve train. However, when the bolt remover broke, did you attempt to piece what you had with what remained in the head to make sure there weren't fragments that may be in the valvetrain? Maybe a chunk of that tool from when it broke landed on a camshaft or something and is contributing to the noise.

Another possiblility is that when you installed the cover with the RTV gasket maker, a section of the RTV squeezed out and covered an oil passage and now the cams/valves are not getting enough oil.

Yet another possibility is that you dropped a tool somewhere and it is rattling around on the exhaust manifold or intake, etc. If you're lucky, this will be the case.

Bottom line is this engine is not a cheap one. If you don't find something laying on the engine and you are pretty sure the noise is coming from within the valve cover, you may as well remove the valve cover and inspect the cams and valves. If you see any obvious scoring, assess the damage and go from there.

-Rod

[BlueBat]

Originally Posted by shorod

Well, since I wasn't watching over your shoulder as you did the work, it will be very difficult for me to speculate on what may have happened. However, there are a few things to think about. When the bolt broke, I'm assuming you did not have the cover off yet, so no fragments of that bolt should be in the valve train. However, when the bolt remover broke, did you attempt to piece what you had with what remained in the head to make sure there weren't fragments that may be in the valvetrain? Maybe a chunk of that tool from when it broke landed on a camshaft or something and is contributing to the noise.

Another possiblility is that when you installed the cover with the RTV gasket maker, a section of the RTV squeezed out and covered an oil passage and now the cams/valves are not getting enough oil.

Yet another possibility is that you dropped a tool somewhere and it is rattling around on the exhaust manifold or intake, etc. If you're lucky, this will be the case.

Bottom line is this engine is not a cheap one. If you don't find something laying on the engine and you are pretty sure the noise is coming from within the valve cover, you may as well remove the valve cover and inspect the cams and valves. If you see any obvious scoring, assess the damage and go from there.

-Rod

Rod,

Thanks for the response. I was thinking on the same lines. I originally thought it was something in the manifold and looked up and down but didn't see anything. Then I thought about that bolt that broke and thought maybe the cover may not be on tight enough because of the missing bolt. I tried to crank it up twice and then left it alone. The cover was on both when the bolt and when I tried to get it out with the rethread bit. The check engine light came on, but I did not have a scanner to get it. Do you think it could be a loose cover due to the bolt?

[shorod]

I wouldn't expect that the missing bolt would cause the cover to distort enough when the remaining bolts are tightened. I'm also glad to hear that your attempt to remove the broken bolt was done with the cover still in place. That should certainly minimize the risk that a fragment of either was introduced into the machined parts.

You may want to see if your local chain auto parts store will loan you a scan tool to see what code was set. They will probably have you give them a refundable deposit for the tool.

-Rod

[BlueBat]

Originally Posted by shorod

I wouldn't expect that the missing bolt would cause the cover to distort enough when the remaining bolts are tightened. I'm also glad to hear that your attempt to remove the broken bolt was done with the cover still in place. That should certainly minimize the risk that a fragment of either was introduced into the machined parts.

You may want to see if your local chain auto parts store will loan you a scan tool to see what code was set. They will probably have you give them a refundable deposit for the tool.

-Rod

Rod,

I finally got a hold of a code scanner and pulled the following code:

P0193 Fuel Rail Pressure Sensor Circuit High Input

Do you have any input on this? I don't know if it has anything to do with the knocking noises or not or with the valve covers since I also changed the PCV valve.

[shorod]

The P0193 code is listed in the factory service manual as having the following possible causes (FRP = Fuel Rail Pressure):

• FRP signal shorted to VREF or VPWR.
• FRP signal open (gasoline only)
• Low fuel pressure (NG only)
• Damaged FRP sensor.
• Damaged PCM.
• High fuel pressure (caused by damaged fuel pressure regulator) NG.

Did the code scanner you got ahold of happen to be a scan tool with datastream capability? If so, there should be a parameter for the fuel rail pressure which may help to determine if the code is being set due to a shorted or open sensor.

Unfortunately, I doubt the pressure is the cause of the noise you are experiencing, but if you managed to pinch a wire in the process or assembling everything, maybe there is a wire fragment contributing to the noise?

-Rod

[BlueBat]

Originally Posted by shorod

The P0193 code is listed in the factory service manual as having the following possible causes (FRP = Fuel Rail Pressure):

• FRP signal shorted to VREF or VPWR.
• FRP signal open (gasoline only)
• Low fuel pressure (NG only)
• Damaged FRP sensor.
• Damaged PCM.
• High fuel pressure (caused by damaged fuel pressure regulator) NG.

Did the code scanner you got ahold of happen to be a scan tool with datastream capability? If so, there should be a parameter for the fuel rail pressure which may help to determine if the code is being set due to a shorted or open sensor.

Unfortunately, I doubt the pressure is the cause of the noise you are experiencing, but if you managed to pinch a wire in the process or assembling everything, maybe there is a wire fragment contributing to the noise?

-Rod

Yeah, once I read that code I figured that it wasn't likely related to the other problem. I had a difficult time trying to dislodge the harness when I changed the PCV valve - my hands just aren't small enough.