Can't find the oil leaks..on 335

[TxDarth]

Ok folks I have replaced the oil filter remote mount seals, the valve cover gasket,etc The oil filter could have been leaking accounting for front leaks but I still have oil leak at the rear - looks like it is coming down from top end on the bell housing. This why I changed the valve cover gasket the gasket was good - no oil in spark plugs, no oil past the gasket on the cover or the head surfaces - everything looks good in that area.. At a loss as to where the oil is coming from....:eyecrazy

[Rodarbal]

I replied in another thread where you asked about this. Have you done your oil pan gasket? Mine was leaking towards the backside and it dripped right where the pan and bell housing meet. If your oil pan gasket is relatively new then it could be your rear main seal.

[TxDarth]

I replied in another thread where you asked about this. Have you done your oil pan gasket? Mine was leaking towards the backside and it dripped right where the pan and bell housing meet. If your oil pan gasket is relatively new then it could be your rear main seal.

As I said there it is coming from up higher, even where it would be associated with rear main seal... but I thank you for that info or reminder, I am looking every wher!

[jclausen]

is the valve cover gasket pinched, I would look around the back with the mirror and flashlight

[TxDarth]

is the valve cover gasket pinched, I would look around the back with the mirror and flashlight

I am replacing it now but could not see where it had been leaking when removed. Dry on both sides of the gasket when removed.

[Old525i]

When I replaced the valve cover gasket, the rear seal still leaked. When I replaced the entire valve cover, then the leaks stopped. There is a valve located towards the rear end of the valve cover, located between cylinder 5 and 6 that helps maintain the correct pressure inside the engine. Replacing the entire valve cover took care of the pressure issue, therefore allowing the seals to work as expected.

When the engine is running, open the oil fill cap to see if you have excess pressure. In general, there should be a slight vacuum present.

This was my experience with my car. If you have a friend with a similar car, I would ask to open the oil fill cap with the engine running to help guide you as to what could be wrong with yours.

[TxDarth]

I am going to put a catch can mod on it too. I was told this will help with leaks going forward.... I would still like to know where this leaking tho - I can't see anything wet on top just down below. It is too high to be the rear main seal but it comes down the bell housing and side of the block. I am just wondering if the turbo is causing it by pushing it over to the engine....It is so damn tight you can't see any thing under there.

[Old525i]

How about power washing the engine, letting it dry or dry it with a nice leaf blower and then turn it on while up high on the lift?

In my case, the oil filter contraption in the front of the engine, the camshaft sensor on the front of the valve cover was leaking all the way to the water pump (via the engine wiring harness), and the rear oil seal. The camshaft sensor leak gave the impression it was the main front oil seal, but lucky me, I gave up on replacing the seal because I didn't want to invest in more BMW tools. Eventually the sensor leak went away with the new valve cover.

Prior to replacing the valve cover, I could turn the engine and see an oil drip come off the junction between the engine and transmission at a rate of a drop every minute. I didn't want to go through the trouble of fixing it myself, so I took it to a local independent BMW who diagnosed the valve cover to be bad. Anyway, they didn't want to touch it (the car had 230k miles: too old to salvage according to them)so I took it home and over the course of a few weeks I replaced the damn cover (around $400) plus a bunch of other sensors.

[TxDarth]

How about power washing the engine, letting it dry or dry it with a nice leaf blower and then turn it on while up high on the lift?

In my case, the oil filter contraption in the front of the engine, the camshaft sensor on the front of the valve cover was leaking all the way to the water pump (via the engine wiring harness), and the rear oil seal. The camshaft sensor leak gave the impression it was the main front oil seal, but lucky me, I gave up on replacing the seal because I didn't want to invest in more BMW tools. Eventually the sensor leak went away with the new valve cover.

Prior to replacing the valve cover, I could turn the engine and see an oil drip come off the junction between the engine and transmission at a rate of a drop every minute. I didn't want to go through the trouble of fixing it myself, so I took it to a local independent BMW who diagnosed the valve cover to be bad. Anyway, they didn't want to touch it (the car had 230k miles: too old to salvage according to them)so I took it home and over the course of a few weeks I replaced the damn cover (around $400) plus a bunch of other sensors.

I just replace all the seals associated with the oil filter/cooler and the valve cover. While I had the cover off I checked closely for cracks and found nothing. I am going to add catch can to replace the PCV system in the valve cover as everyone I have talked to says do it... I am waiting on a new water pump and thermostat to arrive - new hoses also.