Unfortunately, they are almost impossible to replace without disassembling the engine.

Yah, it was my Porsche. Don't know where the faulty pulley came from; it was not long after the alternator had been rebuilt so maybe the auto-electrician put a bung one on there! And getting the exhaust repaired wasn't all that expensive - it just broke a pipe.

More recently, it has undergone a head replacement. I'm picking it up in an hour. That was a very long piece of work. And expensive!

Wade.