My 08 Justa now has 172,000 miles and recently developed a bad oil leak. At first it appeared the oil pan gasket was the cause. Looking further, the leak was caused by the failure of the rubber gaskets of the oil filter mount.
The filter mount bolts to the engine block with the four bolts shown. Behind this there are oil passages and <importantly> a coolant passage. There are these two special rubber gaskets; these pieces become hard, brittle with age and heat. They will eventually crumble to the point of failure as mine did.
Significantly, while the replacement of the gaskets is simple *once you get to it*, the getting to it part is a huge amount of trouble. It is necessary to remove the exhaust manifold in order to do this and THAT is a large process.
The bottom line: IF you are doing other work that requires removing the exhaust manifold, maybe having cylinder head work done (OR if you are removing bodywork/ sheet metal and have access to the area) PLEASE pull the mount and replace these gaskets while you have the access.
NOTE: it is not necessary to drain the oil to do this, BUT(!) it IS necessary to drain the *COOLANT* as there is a coolant port in the block that is also sealed by this.
Below is a pic giving you an idea of what I had to pull off *just to get access*. If you are in there, don’t skip the chance to do this preventative repair.

Thanks for taking the time and effort to share your findings. I’m fastly approaching 155k on my Mini and will keep this in mind when replacing my turbo.

This is good advice, it’s a pretty notorious spot for leaks, if you are in there, it’s worth the forty bucks for the gasket set. Mine was leaking and dripping onto the exhaust and burning off, so it never left any sign on the ground. Fixed it when I did my turbo. Since you are already in there. If you have an S consider replacing the auxiliary water pump while you are in there too.

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