Oil Leak, but can't find the source

[drewusmaximus]

<p>
Hey all, 2011 328xi auto 108k I noticed an oil leak, but I can&#39;t seem to find the source. I looked at the VCG from the front and sides and all three sides are clean and dry, but I can&#39;t see the rear of the VCG. I looked under, cleaned the pan, drove around the block, put the car on ramps, looked under and it was wet again. I can&#39;t see the VCG from down there because of the differential and mating seam being in the way. In the pic, the oil seems to be in the white circle area. I looked at the OPG, to the left of the circle. I do see a little oil, but the oil can be splashed onto that section from wind. I don&#39;t know where the common leaks come from on the OPG. Can it be an axle leak? The driver side CV axle was replaced from the PO and it looks clean and dry. I&#39;m not sure where to look for an OPG leak or an axle leak. It seems impossible to see if the VCG is leaking from the rear from under the car. I can&#39;t even get my hand back there to feel for wetness, but there&#39;s no il by the manifold or on that side of the engine. It&#39;s all clean. This site explains my issue to the T. https://germanformula.com/e90-bmw-32...t-leak-repair/ And my plastics and skid plate looked exactly like in the site pics. I know it&#39;s not common for the main seal to go, so it leaves me with two probabilities; VCG or OPG. I just can&#39;t confirm, but according to that site, it&#39;s probably my OPG. sigh...&nbsp;</p>

[dworthy]

You can go back and edit the text.

So I would get an inspection mirror first. The order of gasket failures on the average BMW are as follows: 1. Valve cover 2. Oil Filter Housing 3. Oil pan 4. F/R main seals.

The amount of Oil pan gaskets I have seen fail are very low, just like F/R main seals. At 11 years, if you don't have any records of the valve cover being changed, I would start there, as they tend to fail around 10 years or 100k miles.

[JDStrickland]

The N51/N52 leak from the Oil Pan Gasket, too.

Using the list of dworthy, the leaks are in the order he gives for earlier engines. Having said that, your engine only has 107k miles and given the experience I have had, I would at least check the oil pan before replacing anything else. I bought my car 2 years ago with 67,000 miles and the guy that did my PPI said that the oil pan was leaking. The seller installed a new pan gasket before I took delivery. Then about 2 weeks later I took the car for some recalls and the BMW dealer said that the oil pan was leaking. I told him that it was fixed two weeks ago and maybe they didn't clean up the mess. The mechanic at the dealership wiped it clean and checked again, it was okay. I have not had a single drop of oil on the floor of my garage so I'm prone to saying that the pan gasket should be checked. The list of fails is good for previous models, but using that thesis I should not have seen the pan gasket fail before 65,000 miles. My caveat is that maybe the list has changed with the introduction of the N51/N52 motors.

[kybmw12]

In my experience, valve cover leak is often accompanied with smell and sometimes visible smoke in the engine bay as the oil burns on the exhaust manifold.


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[drewusmaximus]

In my experience, valve cover leak is often accompanied with smell and sometimes visible smoke in the engine bay as the oil burns on the exhaust manifold.


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At some point I think the PO got the VCG and OFHG replaced, based on the old gunky oil accumulated at the front of the engine, under the OFH and on the skid plate/plastic shields. What I see is the OPG wet. I'm not losing any oil at all. It's just wet. I can live with that for a bit since it doesn't drip.