Oil pressure light is on constantly but runs well, and levels are correct.

So from that I can only conclude that since its running OK you have not done what anyone with any common sense would have done which is get a garage to check it.

The oil pressure light does not mean "if it runs OK carry on and ask on a forum" it means "stop as soon as its safe to do so, shut off engine and call for help".

Have you read your hand book?

Totally unbelievable.