Hey guys,
I have a 2003 with 80K. Mods are only exhaust and air filter.
I first notices a lower tone from exhaust.
Then a oil burning smell at stop lights.
Then a very big cloud of smoke at startup.

Pulled all the plugs and one was black!
Performed pressure test and all of the are right at 175Lbs. EVEN THE BAD SPARK PLUG CYLINDER??
I'm not sure what to do next.
Sell it I know

 

Ok, before you go off the deep end. Change your plugs and oil. Look for oil leaks, it's possible you simply have a bad valve cover gasket with an otherwise healthy engine.
Go back and pull the plug that was oiled after 500 miles. If so you have the option to change that valve cover only.
Let us know what you discover.

 

How does the valve cover gasket get oit into the cylinder. Sorry for the dumb question.

 

The access point for plugs is midline on the cover. If the gasket is tired, gravity drains oil into the plug area causing a fouled plug, possibly misfire and exhaust smoke.

https://www.bing.com/images/search?q...FB97BCD3D9EA33

 

Would the oil need to leak all the way down the spark plug threads to enter the cylinder?
Here are a few pictures of the bad looking spark plug.

 

Yes, that's exactly what happens. IIRC Nissan doesn't sell just the gaskets but rather new valve covers with the gasket already bonded to them and they can be pricey. I understand you can find them on Ebay, some users have used Maxima covers with slight modification. I haven't done mine yet at 108k, so I'm not an expert.
Jump on Google and search VQ35 / 350Z valve covers, you'll find the thread here to help sourcing and mb a DIY guide.

 

I changed the one plug and the car still is boggy. Still burning oil I can smell it.
Today I ran some seafoam and still no difference? Ugg

 

duplicate post..

 

You may need to be persistent to find the problem(s) but you still have multiple options based on your time and buget. You can have a compression test and a leak-down test done to give an accurate idea of engine health.
If it were mine, I'd check the air filter, finish changing all plugs, run an injector cleaner like Techron, new PCV valve and test drive. Burning oil smell can come from lots of places-rings, valves, valve covers to name a few. I'd also look at where the valve covers seat for leaks. You already know one plug is fouling bc the valve cover seal is failing. I would budget the time and money to replace the one bad cover if not both. If you don't have the time or interest now would be a good time to sell to someone who does.

 

sounds like worn valve guide or bad valve stem seals.

 

Pulled new plug and it was black!!! I'm guessing power pack is bad? Would this cause all the smoke?

 

Your probably right with a bad valve seal after thinking about it. The plug is wet but black.
I will bull that valve cover and check it out.

 

Lots of oil here. ???
Image is 180Deg. Sorry

 

Check the PCV system. check the hoses.
looks like alot of oil in the intake. you might be getting run down into the cylinder causing the problem.

With that much oil in the intake you could have failed PCV or rings... but you say your compression is good.

did you try a leak down?

 

This is a tough diagnosis for me. Leak down test does not point to a specific problem. So Iputthe car back together and took it to the Nissan shop. They said an oil ring on the piston.
They also said the will not just repair the ring! (UGGG) they want to sell me a used long block.

So now I'm stuck with a car I don't know who to take it to.

 

get a qualified tech to do a compression and leak down test. of those check out i would blame the PCV system.
If the leak down shows leak down you have bad rings or valve seats. the rings would cause the oil. the valve seats would not.
easily checked during compression check by holding a lighter at the oil fill cap . or holding a lighter near the intake/throttle body and watching for air movement.
or even adding smoke to the check.

that much RAW oil in the intake will run down a intake runner and clog the plug quickly.

I would not condem a ring untll i had wet/dry leak down tests. might be able to use/try a catch can awell.

stealerships are stealer ships.. 95% chance that the tech just looked at it about 5 minutes. checked what you complained about. pulled a plug or two and wrote you up a ticket for the most expensve way to fix the problem that he makes the most money from with the least hassle.

 

This happened to me at a Ford dealership. I had a Turbo Ford Probe that was running poorly. They said I needed a new engine. It turned out to be a bad plug wire.

 

Ford dealership told my step father that his turbo was blown in his F-350 and gave an absurd figure to replace it. I looked at it for 5 min and found a charge pipe coupling blown off. Fixed it with a flat head screwdriver for free