R56 Mystery Oil Leak - Checked All Usual Culprits
#1
Mystery Oil Leak - Checked All Usual Culprits
I’ve only had the car - 2009 S - for a few weeks and have a good sized oil leak on my hands from the passenger side. At first, I saw that the crank seal was incorrectly mounted so I replaced that and it did stop leaking from here. However now I’m seeing quite the leak, especially when under load. The weird part is I see nothing when the car is running and I’m looking all over the front (side) of the motor with the wheel arch removed. The oil clearly sprayed over everything on that side when driving, but I’m at a loss as to where it’s coming from. Any other culprits I’m missing? I’ve checked:
- crankshaft seal
- oil pan gasket
- timing chain tensioner
- valve cover
Would love some insight if anyone has thoughts not found when searching the forum. Many thanks!
- crankshaft seal
- oil pan gasket
- timing chain tensioner
- valve cover
Would love some insight if anyone has thoughts not found when searching the forum. Many thanks!
#2
There's 3 bolts holding the timing chain guides that have o-rings. They might be loose or leaking. Here's a pic from realOEM showing items 13 and 15. Unfortunately, the timing chain should be removed and best replaced to get at them. Here's a good procedure if you want to try it --- https://bmwrepairguide.com/mini-r56-...er-n12-engine/
#3
#4
PCV line from back of the Valve Cover to the intake manifold is a common leak source. Either a loose connection or a damaged hose / fitting at the VC. Whole lot easier to check. If there's oil in the other PCV line --- from the VC to the turbo air inlet, you might have excessive crankcase pressure or a bad VC. Not likely your leak source 'cause that hose is on the other end of the engine. If you have a PCV line going to the intercooler, you better get the hose routing verified / repaired by an experienced Mini mechanic.
#5
PCV line from back of the Valve Cover to the intake manifold is a common leak source. Either a loose connection or a damaged hose / fitting at the VC. Whole lot easier to check. If there's oil in the other PCV line --- from the VC to the turbo air inlet, you might have excessive crankcase pressure or a bad VC. Not likely your leak source 'cause that hose is on the other end of the engine. If you have a PCV line going to the intercooler, you better get the hose routing verified / repaired by an experienced Mini mechanic.
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