M35 - Found oil leak cuplrit

[CPJ LB]

hey guys…I was doing some basic maintenance over the weekend with the M - cleaning, checking fluids, etc… took the car for a drive in the city and on the fwy… I started to notice an oil burning smell — WTF!!?

went back home and popped the hood and could still smell the hint of burning oil…after letting the engine cool down, I started to look and probe around the engine bay…Found a slight leak from back of the engine…

The specific area that had oil residue was from the camshaft position sensor area (both banks)…I let the car car cool down a little more since trying to put my hand back there I could still feel the HEAT!

…fast forward 2 hours later. I pulled both sensors out and found that the ‘O’ ring on both sensors failed!! it wasn’t the normal rubber feel, instead it was hardened and inflexible. Looking closer, I found that both had a small tares - thus causing the oil to seep through and out the back…dripping down the back of the engine bay.

Problem solved - I had two extra ‘O’ rings in my tool supply, perfect fit! I don’t have the exact measurement but I took pix with a penny to scale the diameter.

I’ve taken the car out yesterday and today to test for oil leaks and no more oil smell or leaks! I wonder if others with the VQ35DE engine has or had this issue which they thought of an ‘oil consumption issue’. I’m glad that I found the issue early in order to take care of it…

so guys, check your camshaft sensors if it’s been awhile…even if you aren’t getting error codes, then it might be a good idea just to change out the ‘O’ rings while still using the sensors….

hope this helps someone out…

[Wangtang408]

Great find CPJ! Thank you for posting this up, I'm sure it will help.

[Rotty421]

Thanks for doing the tech write-up

[EdBwoy]

Thanks for the handy info man. I can attest that although this might not account for the entire oil burning issues with VQ35s, it does happen and ruins an otherwise clean engine bay. Our i35s leaked at the same spots and I have been to so many stores with my old sensor to find o-rings that will readily fit with no success. Every Nissan we have will take the same size o-ring for the cam/crank sensors... if only I can find them

Any recollection of where you bought your o-ring or what you bought it for originally?

[crweaver]

I've found that these o rings are typically best to get from the dealer. They are not just any plain ole rubber type o rings. Like the large o ring for the fuel pump, they're made to expand when they get warm/hot.

[CPJ LB]

Glad to help out

Thanks for the handy info man. I can attest that although this might not account for the entire oil burning issues with VQ35s, it does happen and ruins an otherwise clean engine bay. Our i35s leaked at the same spots and I have been to so many stores with my old sensor to find o-rings that will readily fit with no success. Every Nissan we have will take the same size o-ring for the cam/crank sensors... if only I can find them

Any recollection of where you bought your o-ring or what you bought it for originally?

I think the spare O rings I had were from Autozone or O'Riely's... I tend to keep the little "nic/nac" pieces just in case...Fortunately it worked out. I just looked on-line right now and found an old post talking about the same issue...someone else on NICO, but different car...wow! He states the size measurement that he found at ACE Hardware.

oil-leak-camshaft-position-sensor-t478013.html

[EdBwoy]

...found an old post talking about the same issue...someone else on NICO, but different car...wow! He states the size measurement that he found at ACE Hardware.

oil-leak-camshaft-position-sensor-t478013.html

Thanks again.

[cruzad3r]

my man !

when are you coming over?

[CPJ LB]

my man !

when are you coming over?

I'll be in CT this June

getting ready for the move....lets meet up once I get situated

[djc1020]

Hey i was wondering did u notice if the oil level decreased when u checked the dipstick b4 the o ring fix?like when u smelled oil how much was actually leaking thru the ring?

[CPJ LB]

Hey i was wondering did u notice if the oil level decreased when u checked the dipstick b4 the o ring fix?like when u smelled oil how much was actually leaking thru the ring?

I didn't check the dipstick...I'm just glad I caught the issue early. My car is hardly driven, but I don't take any chances with an 'oil leak' of any size. Now for those owners that use their M's as daily drivers and may have this leaking issue, they may experience an obvious decrease in oil levels.

When I changed out the sensors, at the surrounding area of the camshaft sensors, there was obvious evidence of oil seepage.

I've followed up on the sensors and there is no oil residue what so ever, so the new 'O' rings are doing its' job

[LouCast]

As CPJ LB stated these o-rings do tend to leak, which I has happened on mine, but also the VQ35DE leaks from the valve cover gaskets, spark plug tubes, and the main culprit the rear main seal, which mine has leaked from. So I too question the oil consumption theory in general as well.

[cruzad3r]

my frikin engine is drinking oil more than usual. it's still great to drive, plenty of power but the constant checking oil level every 1k and add as necessary is really getting old.

i can't believe this is normal issue to all VQ35 engines. What a POS!!!

[LouCast]

Many have stated that these motors consume oil, but I'm passed 200K and the consumption that I thought I was having came down to simple oil leaks that explained the loss of oil. Just check your motor well, make sure you don't have any leaks. Valve covers, o-rings from the camshaft, and crankshaft sensors, and most importantly the rear main seal.

[cruzad3r]

Lou - any chance you can snap some pics of the rear main seal or the general area. i poked around last weekend during my oil change and i can't find anything out of place. thanks

[LouCast]

Look where the transmission meets the engine, at the bottom, if its wet with oil your rear main seal might be leaking. To get to the rear main seal you have to unmate the trans and engine.