Hey guys!

I recently ran into a couple problems with my 04 G35 (150k miles) including what seems to be an oil leak. Initially it started off with a slight oil burning smell and then my car flipping out on me and power cutting off to the engine. After checking the engine codes (and the forums), it was a crankshaft position sensor error. So I got under my car and swapped that out but while I was under there, I noticed there was some oil around the area where the sensor inserts into near the area where the engine meets the transmission. I cleaned up the oil and wanted to see where the oil was coming from. After a couple days, there were no more symptoms of a faulty crankshaft position error (so I'm assuming that issue is fixed) but when I got back under my car, I found some more oil drops in that area. I presume the oil somehow got into the sensor resulting in it acting up but obviously I'm more concerned where the oil could be leaking from. I've attached pictures where the oil leak appears to be coming from. Any help would be greatly appreciated!

(there also seems to be a small leak from near the filter area, but I'm guessing that's an oil cooler seal leak, which I'll deal with later)

Thanks!

 

Oil leaks that I fixed between both of my 04' and 05' (132k and 158k miles) : Valve cover gaskets, metal gasket between oil cooler and oil pan, and my oil drain bolt was trashed and someone actually tried to use silicone hahahaha... replaced that too. Oil leaks are not fun to trace. I pressure wash the engine bay and take it home and jack it up. Use carb or brake cleaner and rags to clean every trace of oil. Drive it for 30-40 mins and return home to check for drippage.

The only other leak I have encountered so far on both cars is a coolant leak at the rubber hose to the oil cooler (water / oil heat exchanger).

 

There's also an o-ring in the oil cooler where it meets the pan. It's a very common cause of leaks when it fails. There seem to be 2 replacement rings that are available through Nissan but they're different sizes so you have to figure out which one you need. There's a thread on here somewhere detailing this procedure with links to the correct ring if you look.

scumbag I don't remember a metal gasket on our 05 but it's been 8 years since I've had it off. If you've never heard of a Fumoto valve google it. My favorite $20 mod I put on immediately whenever I get a new (to me) car. It's a godsend for DIYers who change their own oil.

 

The O-ring you are talking about described in this video:


I haven't had a problem on either car with this yet but will keep an eye out if I have any leaks down the road. The metal gasket is between the whole oil cooler and oil pan. You have to disassemble the cooler itself to change the rubber Oring, it seals between the oil / water jacket.

 

Usually, the source of the leak is going to have drops of oil forming like you see in the photos, but driving down the road can transfer a lot of residual oil around. So, since you don't look under your car every day. Wipe down/clean as much as you can. Put some miles on it and look to see where those drops/residual oil is building up and go from there

 

 

If it's hitting the exhaust manifold it's is your valve cover gaskets or cam solenoid gaskets. Maybe check your cam sensor Orings on the back side of each head. I haven't had one leak but it could. On the valve cover gaskets, they are very hard to get sealed properly. They are pretty easy to check for leaks. You have to clean the bottom edge of the head where it meets the valve cover. Drive and let cool down then use a paper towel across the clean edge to see if oil is creeping out. Dirty oil is easier to trace than clean oil.

 

Buy a cheap telescoping inspection mirror and use a flashlight to find the leak.

 

Thanks for this! When you say "cam solenoid gaskets", are you referring to what I've seen online as the VTC solenoid on the front-side of the motor by the valve covers or the actual camshaft position sensor on the back of the motor?