I own a 2007 350z. Recently I noticed an oil leak around my valve cover. I decided to go ahead and replace the valve cover gasket. Since a massive harness sits above the passenger valve cover it was pretty difficult to get the gasket to sit flush. After I thought I did it correctly I took it for a test drive. On the drive I noticed a burning oil smell which I contributed to the left over oil that came out when I removed the valve cover. However when I pressed down on the gas I noticed I was going extremely slow for the amount of throttle I was giving it. I instantly assumed misfire. Then my motor shut off completely. I tried to start it again and it clicked but nothing else. I flat towed it home and took off the valve cover to see the gasket had actually snapped and wrapped around the cam. I tried manually turning the crank and it won’t budge. There was still oil in the vehicle so I don’t think it was running dry unless an oil line was clogged. Does anyone know what next steps I should take to try and save this car?

 

An exorcism

 

First, don't panic. How much oil was showing on the dipstick when you checked it? If you lost a quart of oil, just clean it up and refill. Next, remove the valve cover and try to unwrap the twisted gasket from the cam without scraping or damaging anything. Pull codes if possible and check to see if the engine turns over easily with a wrench. You'll need to retrace your steps and get some help to reinstall the valve cover gaskets correctly before attempting to restart again.

Keep in mind that a misfire will usually cause noise, so if you have a loss of power combined with the odor of burning oil, it's time to hit the kill switch.

 

There wasn’t much showing on the dipstick at all but still some. I lost about 1.5q I’d assume. the engine won’t manually turn over at all thought. I’m not sure if the bolt is just tightening or if it’s locked.

 

Let the oil completely settle into the sump before you take a measurement. If there's a bigger loss of oil, you may have indeed seized it up. The gasket will have to be removed first to determine if the engine will turn over.

 

I would 2nd what DK Mura said and if the engine turns over than do a compression test and if the compression test comes back good than replace the filter, drain the oil, and refill. If you wanted to, you could replace the filter and refill the oil after 20 to 30miles as a flush.

If the engine does not turn over and/or if compression is out of spec than you need to replace the engine -

 

I removed the gasket, coil packs, and sparkplugs. The crank won’t manually turn whatsoever, which is weird to be because I would have assumed there would be atleast an inch of give before i hit the locking mechanism.

 

Sounds like you will be replacing the engine

 

did you take photos of the engine showing how the gasket was wrapped up? that would be helpful here. as soon as Cam was interrupted, the engine would have stopped. maybe the other bank was still going. it depends on how long you kept going at it at the first sign of trouble.

so if the cam was stopped in the head by the twisted gasket, that would have locked the chain which would cause the crank and the other cam to stop also. so I don't see how the Pistons were even moving as soon as that happened. you could try removing the timing chain cover to take a look.

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I could be wrong but my thinking is the gasket caused significant resistance on the cam but not enough to completely stop it. Causing the camshaft position sensor to tell the ecu to engage the locking mechanism. However I’m not sure if the cps has the ability to lock an engine.

 

That's about as lame as my seeing the subject line and thinking "Who's seizing it? DEA? IRS?"

Ohhhh....... "seizing" as in engine locking up... well don't I feel like an idiot who watches to many episodes of "Drugs, Inc."

 

This is interesting. Failing a valve cover seal job so badly that it possibly ruined the motor is quite the feat.

First step is a photo of the gasket wrapped up in the CAM.

Then check oil level and a pic of the dipstick too.

Then drain the oil and pour it through a cloth. If you siezed the engine by spinning a bearing, there will be plenty of evidence. Go ahead and throw that picture in too.

If the oil is clean, then the next step is probably to remove the Cam shaft, hoping that the stuck gasket is what is preventing it from turning over.

If the oil is full of copper/bronze sparkle then go hit up ebay for a new engine.

Are you trying to turn the engine over with a breaker bar on the crank?

Are you sure your battery/alternator did not die from the oil bath and cause it to not be able to crank?

 

well in fairness to you, seizing is a completely incorrect word to use to describe an engine freezing up. engines have freeze plugs, not seize plugs. since seizing means taking possession of, I don't get how that dumbass word was ever attached to an engine failure. but that's this damn culture for you.

 

I was thinking enough oil leaked out from the valve cover not being sealed … I can’t imagine that, for how soft and plyable the seal is, that it got stuck on a lifter bucket and that’s what causing the seize-up-ness …

Noah - have you tried reverse direction rotation of the engine? Or is it locked-up in both directions.

 

sadly both directions. I’m assuming you’re right and enough oil leaked out of the gap between my valve cover causing it to seize

 

You live, you learn -
My ‘dumb’ moment was when I over-torqued the oil pressure sensor and cracked my upper oil pan …