I've fallen into the trap before of misreading the level, by reading before all the oil has drained into the sump, including one memorable occasion on an Italian Alpe. I was revving hard to get up the steep mountain and it was getting smelly. I thought it was oil, which was low when I checked, so I filled it up, and then had black smoke coming out the whole way on the way down because I filled it up too far.

I have a light question as well: my oil light is on at ignition, so there's no trouble with power to the bulb, but it has never come on to warn of low oil, even when the level has gone right down below minimum.

Can anyone tell me which part is failing?

Tom