Hello,

I have an 04 G35x with 96,000km I bought used last November at 88,000. The previous owner did not maintain the car at all so I have been slowly getting it back up to speed.

Yesterday I changed the spark plugs and two of them had quite a bit of oil on them. I also ran a vacuum gauge test to see if it was the valves but the test showed everything as normal. Would it be a problem with the cylinders or pistons? Is this a major concern? I only changed the spark plugs because I was getting poor MPG at 400km for a full tank... (and that's running it bone dry too) However I am feeling a significant change in gear shifts from 1st-2nd, it is really smooth now. (5AT Sedan)

Many thanks for your help

 

valve covers??

 

^^ Would be my guess too as they are known for leaking around the spark plug gasket in the valve cover, I just changed mine a couple weeks ago and had oil on my #5 plug. Is the oil on the porcelain side or the other side?

 

yea,
seems to be a common issue and you have to purchase new covers.

 

Definitely valve cover, had the same issue had it replace under warranty or you can contact R&D factory, they sell a valve cover and o-ring replacement kit. They are a sponsor on this forum, check this thread for more details https://g35driver.com/forums/engine-...ampaign-3.html

 

There is also this as an alternative, http://my350z.com/forum/engine/54492...ve-covers.html

 

Guys, thank you so much for your help! I called my mechanic and he was so shocked that I changed the spark plugs. He said I need a professional and to get education about this stuff "not from a forum" LOL. (Need a professional to replace spark plugs my ***...)

Anyways, is there a DIY on how to do this? I really don't want to pay him/give him the satisfaction of doing it for me.

 

https://g35driver.com/forums/engine-...ve-covers.html one showing how to diy with the R&D kit

 

What if the oil is on the screw thread side?