So I had the infamous oil leak problem on my max and took it to my mechanic. He stated the issue I have is common on maxima's (which I knew) but he insisted only the gaskets need replacing. After he did the work and also replaced plenum, spark plugs, and clean TB. I ask if the valve covers looked okay and he stated they are fine. He stated the problem was the gaskets hardened and cracked.

Is everyone having to replace the valve covers too or just gaskets?

 

I know the gaskets go bad but usually people here upgrade their valve covers to 06 ones I believe. So I'm assuming the valves r bad?? Not to sure on thisone..

 

The rear cover to my knowledge is the one that normally replaced as it cracks, and most of the 03 owners purchase the 04 version as the quality is slightly better and it is I believe priced a bit better than the 03 version.

 

Replaced mine recently with the valvecover and gasket both. My gasket was definitely hard, but my oil was coming from the seals around the sparkplug holes. Oil was slinging out around the seals and running down the valvecover-you could see the trails. The new valvecover had much smaller sealsthat required effort to get around the sparkplug tubes. Much better fitment.

 

If your oil leak was caused by a bad gasket, then yeah, replacing the gasket fixes the problem. However, the common problem here is in the fitment around the #3 spark plug tube where it passes through the VC. This is what fails when people say "cracked". That was my experience.

The 6th gen VC does not suffer from that design, and costs less than half the 5th gen cover does. I'll go out on a limb here and say that only the original equipment rear covers are failing, and that Nissan's part supply line of replacement valve covers have a slightly different design than the original part. Unfortunately, I don't have any pictures to back that up, just second-hand observation from my mechanic. I trust him, so I'm assuming (hoping) that's the case.

 

Why did he replace the plenum? That part is certainly not prone to failure.

 

This was my understanding as well, that I have only heard of the rear valve covers usually failing and needing replacement. I believe you are correct on the pricing as well.

 

I don't have a 3.5 but don't you have to pull the IM to replace the rear VC gasket? If so, then you'd need to replace the gasket..

 

My mechanic mentioned the parts to me and i heard plenum, I figured it was also bad. I did however ask if the spark plugs had oil on them and he stated they did not but my exhaust had oil all over it.
I can still smell the burnt oil when I drive my car but it is not as strong as it use to be.

I think I will be fine after I spray some engine de-greaser on it, next project engine mounts....