I had a 1991 318i a year or so back; no ticking from the head - lovely; 106k miles.
Then the bottom end went on the motorway! I thought they were bombproof.
My mechanic took it apart and said this was why he thought it had happened.
There is an inner and outer 'sump'? Can't remember exactly how he described it, but if you take off the 'outer' sump casing there is another section which includes half of the oil take-up. He said that a few of the bolts from this inner section had worked loose (they were in the bottom of the sump proper when he took that off) and the seal on the oil take-up had opened slightly.....
So when the engine was working hard and the oil hot and thin, air was being sucked-up by the oil pump instead; well as you can imagine, unhappy things happened.
Anyway next time you do your oil change, and you have the time, it may be worth taking off the sump and checking the next layer of bolts.
I'll tell you why - I got a good replacement engine (with 98k allegedly) and my mechanic said before he'd fit it he'd check that inner 'sump'. He found the seal WAS still ok, but there WERE A FEW BOLTS IN THE SUMP PROPER.
I was reminded of this because I found the cylinder head and manifold in my garage today, taking up space. If any Zoner wants it, (and if you've read this far you deserve it!), you are welcome to it. I can't guarantee anything about it, but I did 3k miles before the bottom went, and it was very good.
I travel around from Gatwick to Worthing and a bit to the sides.
