If you were down a cylinder, I would expect to see a significant loss of power. That's weird. I would want to see another compression test done on it.
I too am losing a substantial amount of oil but, I know I have a leak. Just haven't pin pointed just where its coming from yet.

 

Just removed my valve cover to put on a new gasket. It looks like lots of oil in there. Is there an way to clean it without removing the whole part? And is it drivable like this for a little while until i can get a new valve cover?

 

there's always a reason its called "cover".... if u drive ur car like that just for like let say 0.1 mile, ur whole engine will cover with oil.. lol

 

dust and debris might as well come inside ur engine and "ordering new engine" time!

 

haha, i didn't mean drive it with the cover off. that would be dumb obviously. After i put it all back together with the new gaskets, with that bit of oil in the valve area.

 

you might want to clean all the plenum and valve cover as they are out now. clean all the sludge and everything. you can use seafoam product, but the spray can one.. not the bottle! and wipe the manifold with towel around that gasket area. and dont forget, cover that manifold! cos u dont want any debris or dust inside there. cover it with some paper towels.

 

I am not sure what you mean... You want to clean the top side of the head? are you concerned about the oil up there? There is supposed to be oil up there. You can clean the inside of the valve cover if you want. I wouldn't even bother with cleaning the plenum, personally. With the egr system and all hooked up, it'll just get that same stuff in there again. Why are you buying a new valve cover? Why not buy the valve cover seal kit from R&D Factory in CA? Its way cheaper and only requires slightly more work.

 

@jribbe101. What are your oil change intervals/ what oil do you use? What is the mileage on your G. Curious after looking at the color of your valvetrain...btw nothing to be alarmed about, just darker than what I'm accustomed to seeing!

 

G35 2003 Coupe 6speed
121,246 miles

For the first 30k miles I used mobile 1 synthetic. I then used royal purple and have recently switched to amsoil signature 25k mile. I use amsoil and K&N oil filters. Oil changes are usually between 4k-5k miles.

The valve covers / intake manifold have never been opened except for yesterday. I cleaned everything off with berryman carb cleaner. The car runs very smoothly now after cleaning all that. I am almost on a half tank of gas, and have gone 201 miles. Although that is on the highway mostly. A little better than I was getting before the cleanup.

 

I have these Maxima seals, they arent the correct part. The outside diameter and design of the seal is different.

 

So, are you saying the Maxima 2000-2001 V6 3.0 is not the correct part seal?

 

Affirmative. BTW, thanks for reminding me I need to sell the set I have!

 

my lower plenum looks just like that

 

Well, someone must know the correct seal part number or car model and year??

 

R&D Factory's best kept secret! I gave up on attempting to locate it