"John Burns" > wrote in message
...
> I'd suspect a vacuum leak alright.

Thanks John - how do I find it?

> If it's the later 24 valve M50 engine you may need a new water pump. The
> early ones had a design fault and the plastic pump section parts company
> with the metal core. Could also be a badly bled cooling system.

It's an M20. I did have a job bleeding the cooling system after refilling
when changine the thermostat as I'd never done it before, but I reckon I got
it right in the end (god knows it took long enough - followed the Haynes
manual, until only fluid came from the stat housing and rad bleed screws).
Could air in the cooling system affect the engine in this way?

> See my site for reviews of UK BMW specialist garages.

I did, and took my old E34 518 to RAW in Corydon for a service a year ago,
and was very pleased with them!

Many thanks,

Jamie