I've noticed that I am losing/burning/hiding oil somehow on my 2004 G35, about 2 qts every 4k miles. I'm not sure where its going, so I took off my PCV valve last night, to discover it had oil on it. I shook it and it rattled, but still sounded like oil was inside so I cleaned it.

Could this have been the culprit to why I'm losing oil? Should I put an oil catch can inline?

EDIT: sorry I meant the PCV valve....

 

Positive crankcase ventilation (PCV). Change it as a routine maintanenance for the little amount it cost and has an effect on oil consumption. How many miles do you currently have on the vehicle and just pick one up but make sure it is OEM GENUINE.

 

it has about 84k on it right now. I've read about people leaking oil in their number 6 spark plug area, so I was going to check this, but I don't think it would cause that much oil consumption...

I cleaned it with throttle body cleaner and this made it rattle alot nicer if that makes sense, didn't sound like there was any oil left in it. But I'll just get a new one since they are cheap.

It doesn't smell or look like I'm burning oil really. and I'm not leaking it anywhere, so I can't think of anything else it can be..

 

Your spark plug seals are common known issues and with the VQ design what I have seen is valve guide seals are weak along with piston rings. Specifically you see this issue in the rev-up but also you will get a similar consumption with non rev-up as well just lower amount of consumption. As these engines get older they will end up consuming more oil. You will see oil go out the exhaust chamber (INTERNAL - valve guide seals issue) especially with free flowing exhaust that will end up causing a vacuum and suck oil in the exhaust valves and out the back end into the cats.

You see the rate of oil consumption increase when you modify intake and exhaust to be more free flowing that causes the oil to seep through piston rings and valve guide seals. With the mixture of piston ring, valve guide seals, pcv, valve covers leaking, Plenum having oil, and any other specific leaks to your vehicle is where you see the oil dissappear.

All you can do is try to find a thicker 30 weight oil or switch to conventional oil which will slow down consumption. I notice around 2k miles is when my rate of consumption increases and by 3k miles the consumption has wiped away 1 qt of oil. 1qt for 3k miles is safe which is less than industry standard of 1qt for every 1k miles, but I prefer to change oil at 2k miles right when it starts consuming faster. I just choose regular conventional oil and change it often.

 

Damn, I was hoping it wasn't something as serious as the piston rings. I guess its not that bad though. I'm going to check my spark plugs for the valve cover leak problem. Maybe fixing that will slow it down..

 

if its the piston rings or valve seals wouldn't i see smoke out the back end?

 

Each car is different and the amount of consumption and where the root cause is different. In the rev-up series for sure the piston rings are the cause and along side the valve guide seals were being pointed out at first and being replaced by Nissan via long block exchange. Now Nissan has changed to shortblock and believes the root cause issue to be piston rings. That could be a money saving tactic or the truth and you will not know until you become CEO of Nissan. If you had a very bad case of oil consumption and add a set of test pipes that would worsen the effects and cause more oil to seep into the valves.

Actually seeing smoke out the exhaust is different on each case and how much oil you are burning. I have seen many rev-up that have oil consumption rate increase drastically by adding a full exhaust and notice when they go back to stock it slows down. The only time people notice exhaust fumes having black smoke is upon WOT on the DYNO or if someone is trailing behind you. The consumption is always there in the VQ design but the degree of consumption is different for each vehicle based upon age, mods and oil type.

 

My 03 350z just encountered this recently. Im burning quite a bit. I Switched out my Berk HFC's for ART pipes and retuned. I was never aware that i was burning prior to the swap. 1200 miles later i was 4 quarts low on a non-revup !! i topped off and checked 1200 miles later, then down 1 quart. Who knows where it is going, but i have noticed oil stain on the right side of my plenum opposite of the fill side(by the pcv valve) I also have md spacer installed.

 

OK I found the culprit. I could see there was oil obviously coming out of my oil cap and dipstick holes, it was everywhere. I turned on my car and what do you know, clearly a vacuum leak coming out of the PCV hose. Got a new one and everything sounds good so far. I think that was it...

 

How can you have not leaking anywhere and the next minute have oil everywhere? It's possible you created the leak by messing with your engine and that wasn't the cause of the OC issue at all. Time will tell, keep watching the oil level on your dip stick frequently and make sure it's pushed all the way in....Gary

 

synthetic does no emit blue smoke only dino oil does

 

I have a bad consumption issue. Noticed it with I had the arts and tdx installed. Took it in for a comp test after reading the tsb and the test came back fine. How much is involved in replacing the valve seats. My extended warranty company (which might not cover valve seats) isn't the best. They told me to authorize a tare down to find the mechanical failure. Further more they said of its the rings and it's faulty due to Carbon build up they still wouldn't cover it. I'm at the point to where I'm going to buy a stroker kit and do a cam and valve job to settings right. Since they won't warrant replacing the long block.

 

im having a similiar issue when i remove my oil cap its smoking, however last i checked my oil level about threee days ago it was a little above full so im lost as to what could be causing the smoke and it smells like burnt oil im going to do a oil change this weekend and take it from there

 

Is that after the car is off ?

 

if your referring to me its when the car is off