Hey guys, I am stumped by my wife's 03 Maxima...once again.
It is losing oil severely and I can't seem to figure out where its going. There are no puddles on the ground when the car is parked (even after multiple days of being parked), there is no smoke from the exhaust or residue on the back of the car. The engine runs great. Is there somewhere that the oil could be leaking from that would only leak when the engine is running and/or driving? Any recommendations? I've already replaced both valve covers with the next generation covers and there are definitely no leaks from those anywhere (I don't say that because I'm an awesome mechanic, I say that because that was the first place I looked when the oil kept disappearing after I replaced the covers because I figured I screwed it up)

 

Do you see any oil residue under the vehicle near the oil pan? I'm thinking it may be the oil cooler O-ring which is behind the oil filter.

 

Welcome to the world of VQ35s. If she ain't leaking, she's burning it.

 

Would the bad O-ring account for multiple quarts lost every thousand miles?

Haha, I know thats true! I've been fighting this leak the whole time she's had it, but now its due for inspection and I HAVE to fix it.

 

Motor is gone. Precats did their handy work.

5.7 swap or junk it.

 

Care to explain such a bold statement? The engine still runs great and has been leaking oil like this for a long time so I don't really believe that the engine is gone....

 

Look under the car by the oil pan and by the oil filter and report back.

Child_uv_korn is probably one of the best and most useful members. But I must say he jumps to this conclusion a lot. PTSD if you ask me.

 

check to see if its leaking at the main seal where engine and tranny come togather. I have a leak there but not really worried about it. I just watch the oil level.

 

Multiple quarts per 1k miles would be leaving puddles if it were a leak. This is 100% normal behavior for ate up rings/cylinders due to precats.

 

If you take this route you should re seal and scrub the engine real well with degreaser. Plug all the sensor holes with rags and cover electronics with plastic and electrical tape.
It's not that easy to just swap an engine.

 

Put the car on a lift then check it properly

 

VQ's burn hella oil, when pre cats break apart they get sucked in your engine and kill your piston rings. The engine will still run good....until there is no oil.

 

just saying i removed precats at 184k, and they were intact 100%
edit - I proactively did 6th gen VC's as well at 130k (slight leak on rear not bad at the time)

and with that said i have begun burning oil at small amounts 1 qt per oil change interval (1 qt about every 2000 miles)

its an older car thing a lot of high mileage cars just burn oil plain and simple

not sure about tons, op you never mentioned how much you are burning/ loosing

 

I recently put a new engine in to my maxima after the old one seized this eats oil like crazy i did rear main, both valve covers just did the pcv valve... im gunking my car to see if its leaking becuase I'm not the greatest mechanic if its not valve covers leaking im going to be looking at VTC solenoid and maybe the gasket for the VTC since I used my old VTC and old gasket... it's frustrating and I hope I didn't get an engine that had O rings ****ed

 

It's burning it. Leaks show up on the ground. Been there' done that. On my third motor because of it.
Check it every couple of days to find out how often you need to top it off.

 

This thicker oil burns off a lot slower. Try it out! I have bad valve stem seals, but it's not too bad--slight blue smoke on deceleration. Motor still pulls like mad. I have a Megan test pipe so that i was able to see the blue smoke & diagnose it (someone followed behind me). Good luck.