I would like to start off by saying I am the guy they refer to when they speak of Murphy's Law.
So my wife's little brother is graduating with honors after doing all AP classes. Kid really applied himself and I wanted to do something nice, knowing that nobody else in his family would. I bought a 2002 Nissan Maxima 6spd for 2300$. I got the price down because it was throwing a misfire code and had white/grey smoke. I should have known better but the car is immaculate otherwise. 137000 miles. Brand new tires, brakes, cats, spark plugs, battery, etc. The guy sold it because it was still having problems and he didn't know what to do.
I started taking things apart. I realized that the valve covers both need replaced because the rubber grommets for the spark plug chambers are bad and causing oil to get in there. Unfortunately when I pulled the front 3 spark plugs, the electrodes were gunky and had oil on them. Doing searches that lead me to believe the rings were bad. I checked the back and all 3 spark plugs were perfect. I then compression tested the cylinders (with the front valve cover off and the UIM off--not sure if it makes a difference).
The back all hit 180. The front are as follows- 120, 100, 145. Now I bought this car because I really wanted to get him the best car I could afford. I had a 2002 Altima 3.5 and had to change the engine in it 8 years ago. I swear I paid less for that engine than what I am able to find now. If its under 120000 miles it's over 1200$. I am currently rooting for a bad head gasket or hoping that somehow having the valve cover off skews the test. Any ideas would be very helpful. Codes pulled were P0300 and P0101. Symptoms I noticed when driving it were, it was slow, had a misfire, a tick at low rpm (not rod knock) and the white smoke under any acceleration. It was otherwise a very smooth car. I can assure you this car has been well maintained. The guy was the second owner, bought it in 04 and had money. He took it to a mechanic for everything. I think my trust in the guy made me doubt my better judgement.

 

nice find, BUT it is a well known fact that the 3.5 engines are oil burners and for some reason the front bank of cylinders, on the front of the car, always goes south. Yes, the car might be super nice and clean and well taken care of but the 3.5 always lives to its reputation of an oil burner. One thing to do is take out the cats on the exhaust manifolds and gut those out. Finding another engine at this point, at least in my opinion, is not wort it. Think about it... it will be the same engine you already have in the car. Ideally you would take it apart bore it, if needed, hone it, new rings and all new gaskets and basically have your fixed vs. getting another problem engine.

 

The car got new cats very recently. What I don't understand is that in my searches I'm not finding people with my identic issues. If it were the rings shouldn't the smoke be blueish? Why would only one ring be severely bad. Seems more like a head gasket even though that's not common on these motors. And ideally I would have an extra 2 grand laying around... I do not. I don't believe I have the tools or know how to tackle a piston job.

 

I agree with you. Not too common and the front 3 aren't typically the ones i have read of going bad, not sure where that logic came from. I would look more into the HG issue up front, as in the front 3 cylinders and see from there.

 

Do you have any advice on any further diagnostic steps I can take? Btw Idk if it means anything, but I shined a light down my spark plug chambers and all of my pistons look the same. A good metallic silver with tiny black specs covering maybe 10-20% of what I can see.

 

Not a guru but the oil gunk on the spark plug electrodes is probably due to the valve cover gasket leaking and the white smoke may be from the engine running rich and the ecu is asking for more fuel? Just a thought but id try the obvious and start by changing the valve cover gasket and gromets and replace the fouled plugs first. As for your codes I don't have the book on hand at this very moment but I believe one is cylinder misfire maybe o2 sensor for the other. Try downloading the fsm from here on the forum and address the codes pulled, change leaky gaskets and change the fouled plugs for starters then take it from there.

 

Oil leaking from the top down should not get oil to the tip of the electrodes. The back 3 cyl also have a little trickle down oil on the threads but not on the electrode. I know that I have to buy new valve covers but I need to make sure the motor is salvageable before I spend another couple hundred bucks. A leaky valve cover wouldn't cause a compression of 100 either, to my knowledge...

And I belive the codes I was receiving are random misfire on multiple cylinders and a maf code. As of tackling this job the only code reading was the random misfire and the ses light would blink a lot.

 

Yes, p0300 is multiple cylinder misfire and a search for p0101 finds an MAF code. My experience with valve covers is that it's the rear cover that fails and leaks oil into the plug tubes. When you replace them make sure you replace with 6th gen valve covers. They are cheaper, are bolt on replacements, and the tube seal issue was addressed with this gen cover.

 

Unfortunately, they are not much cheaper any longer, but they are constructed better.

Also, black smoke would be an indicator of massive richness, so the white smoke is a good indicator of a bad HG. Usually fairly common blue smoke = oil, black = fuel, white = coolant/bad HG.

Check the coolant and see what it looks like.

 

Thanks. That's the plan, even though the Nismo Shop told me they don't fit. Is this a part I can get off Ebay, or two risky?

Checked the coolant, looks totally normal. Smoke also never smelled like coolant. I checked the oil and it's super black.

So just to check, on this motor, to have massively low compression (120, 100, 145) on three adjacent cylinders means either bad HG or bad rings, no? And nothing like having the valve cover off can mess up the test correct?

 

 

HEY! Thanks a lot. On the vq35, one has to remove the intake manifold to get to the rear cylinders. In doing so, one would logically remove the throttle body. It seems as though I reached good (accurate?) numbers on the rear cylinders. Are you suggesting, I reinstall everything, and get the car running again before compression testing? Why would depressing the throttle matter if I have disconnected the TB? Can I just attempt the oil test as is?

 

Hmmm... I guess my last post didn't work. I did he test with the oil. After adding small amounts of oil into the spark plug chambers my compression went up close to 180 on all 3 front cylinders. So it looks like it is the Rings. Worst case scenario. I really appreciate all of the quick forum support.