So I picked up an 03 350z and it started to smoke and leak some oil, the smoke seems to be leaking from the passenger side toward the firewall. Immediately I thought it was the valve covers since its a pretty common thing on Z's but After taking off the plenum and everything the gaskets don't look that bad, I see some oil around it but I just don't know if that would do it? There is also oil around the oil filter, I think this is a separate problem like the o-ring leaking because it wouldn't smoke because it got nothing hot to drip on except earth. Any help? Thanks

 

My Z has leaky valve covers and once it sits for a week or more it will smoke from the same area until the oil burns off the passenger manifold. Or do you mean smoke out of the tailpipe? If so then its not the valve covers or the oil plate adapter.

 

Smoke is coming out of the engine bay on the passengers side

 

Are you positive that it is oil leaking? I had a pretty big leak from the power steering pump that made its way down to the oil filter and coated much of the underside from just a small leak. But this probably wouldn't reach the rear valve cover area.

How were your spark-plug tube seals, any oil coming out of them? Although If this was the culprit, I would imagine you'd have a pretty noticeable misfire. Just throwing some more ideas out there.

 

Same thing happened with me a few years back. I would get light smoke coming from that same area. I had a small leak in my valve cover gaskets and oil would seep out and down onto the exhaust manifold. Even though your VC gasket doesn't look that bad it may be time to change them anyway. What year is your car? how many miles?

 

Funny you talk about a misfire, I had one when i bought the car, replaced the coil pack and it was good to go, could this be?

 

03 135K, i dont think the previous owner did much work on it

 

Was your spark plug tube filled with oil when you changed it? Nissan R&D did a poor job with the valve covers on the earlier 350z. I have an '03 as well with around the same amount of miles as yours. The gaskets tend to fail after quite a while and most owners have changed them at least once by this mileage. The spark plug tube seals fail and oil fills the tube and drowns the spark plug as well as the coil pack. Eventually the coil pack fails from the oil saturation and you develop a misfire.

 

Didnt notice anything g out of the usual with the plugs but I’m going to check again