Well it passed it's MOT (UK test) and they did a hydrocarbon test and it came back negative (no exhaust gases in the coolant).

I drove it 80miles watching the temp like a paranoid freak.

The guys still think the pressure builds up in the coolant system too quickly but were unable to test it saying I should take it to BMW.

What’s too quickly, any ideas?

My initial thought is they have no experience with V8's and should stick to tests however until I know for sure it's not worth taking the risk. Off to the dealership to pay $198 P/HR.

Nice !