Oil leak front of engine N54
 

I have a serious oil leak over the front of the engine on a 2008 535i turbo engine. I have changed


1. Oil filter housing to block gasket
2. Oil filter housing to radiator lines gasket
3. Looked at o ring for the oil lines to the radiator and they are not leaking at the engine or at the radiator.


What can it be?

what about you valve cover?

Not valve covers either. Did Check. The oil seems to be below the head gasket area. Covers the entire front, the belt tensioner area, as well as part of the Alternator, and air intake from the turbo to the air filter housing.

Strange.

I had oil on the front of mine as well but it was the oil filter housing causing it. Luckily it was only the portion of the housing in the front cover so didn't have to replace the block side. The housing and the two lines are the only thing I can think of that are up in the front. Did you also change the housing front cover seal?

Oil Filter Housing is very common leak for this vehicle and the Gasket must be replaced. There are a few DIY guides on the web for this if you are handy enough.

Yes, I changed both those oil filter housing gaskets and they were leaking. But, they are not leaking anymore. Something else. Headgasket?

I am stumped.

I put the car on a lift, removed the under trays, and cross plate, clean off the oil let it run in idle for 1 hour and no leaks.

It must be leaking only under load. What could it be? Turbo leaks?

Could you have possibly fixed the issue with the filter housing and are just seeing remnants of oil? I know I had a leak from a car and had oil drips from every crevasse of the car showing up on the driveway for months after the problem was repaired.

Not possible. I washed off the residue, let the car idle for 2 hours and revved at 2000 rpm for 20 minute. No leaks. But it leaks under load while driving. All over the front, dripped onto the AC pump and power steering pump. Onto the air hoses. Down to the plastic underpan and on to the ground.


Stumped....

This is a stretch, but I've been wondering what could leak while driving, meaning an increase in oil pressure not related to engine speed (since you had no leaks when you let it sit at fast idle). One thing that comes to mind is the PS system. Just idling, the PS has no/low pressure. Start turning the wheel as you drive, pressure builds. And it's hydraulic oil. Check to see if the PS reservoir is down. If down, check for cracks, loose cover, damage to PS lines. And the system is right next to the oil filter. It's a stretch, but worth a check.