E61 530i N52 Oil Leak around but NOT OFHG!
 

Hi All!

Picked up a 2005 E61 M-Sport 530i with the N52 motor. It has a strange oil leak around, but not to do with the oil filter housing gaskets that I need some advice on.

The previous owner gave up after changing the gaskets twice, then a completely new housing. Turns out it isn't the OFH at all, not the oil cap, but looks to be coming from somewhere in between the OFH and the intake manifold.

Here are some pictures of where the most oil is found, and is pooling. The valve cover gasket above is completely clean as well, so it isn't seeping down from there. It is a pretty significant leak.

I have just noticed comparing to other N52's, it seems like they have left a bolt out as pictured. Does anyone know are there oil galleries that this bolt should be blocking, or is the bolt being missing causing a poor seal with whatever it holds together?

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Also does anyone have a part number or spec's for that bolt (or can direct me where to find them)? Any help would be greatly appreciated, I am completely new to BMW's!

OK seems I have kind of answered my own questions on this with a little more searching a la https://www.e90post.com/forums/showthread.php?t=321170&page=2

Common fault it seems. As far as I know and based on visual evidence the head has never been pulled on this car so I guess expansion has caused the bolt head to snap off at some point.

I guess the intake manifold will need to come off to be able to get to it.

For anyone else trying to do this themselves, I managed to get it out pretty easily by partially pulling the intake manifold off, sealing up the head and manifold with tape and carefully drilling into the bolt vacuuming shavings as I went.

I was then able to use a sharp square pick to unscrew the bolt.

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Was the bolt here?


https://cimg6.ibsrv.net/gimg/5series...16f659a9fd.png

Thanks. I have N54, but a buddy has a N52K so I gave him a "heads up". The thread was a good read.

Good post. Thanks for the info.

Well after replacing the broken bolt I am still getting the same oil leaking, so it is seemingly only part of the problem.

Next step is to take the valve cover off and check the other three bolts, also I am not convinced the previous owner put new bolts in for the oil filter housing so I am going to source and replace these as well.

Probably most concerning me right now is I am getting oil coming out of the intake manifold stud between #1 and #2 cylinders and also the intake manifold bolt between #2 and #3.

Could turn out to be something more sinister like a cracked head. Hoping this is not the case obviously. I would expect the engine to be having other issues if this was the case.

After further tracing turns out my Oil Pressure Sensor / Switch that sits on top of the oil filter housing is leaking out of the back of the sensor body. At first I thought it needed a further nip up but this made it worse, so clearly is cracked internally and looking around seems others have experienced the same issue. I don't think it is a genuine sensor either, it seems a bit cheap. Second photo shows it leaking out from the sensor plastic body.

At a guess the previous owner over-tightened it when installing into the new oil filter housing. I have a German made one arriving next week, along with a valve cover gasket in the event I need to dig further into the other cylinder head bolts.

I will also be properly pulling the intake manifold off over the weekend to trace this other potential leak.

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