my 2litre petrol spacecruiser will run at normal temperature all day long (tried and tested) and has never overheated - yet!!.but about one minute after its switched off i can hear the expansion tank start bubbling slightly,after about 2 minutes its actually boiling,sometimes blows coolant out of expansion tank,never had to top up in rad cap its always full up,just refill exp tank,anyone else got this problem

- (#7878) nick, 15 Jan 04 15:36

I had the exact same problem with my old 2.0 litre petrol Spacecruiser. I tried new thermostates and rad caps but it would still boil when switched off, sometimes draining a substatial amount of water out of the system. It was fine under normal driving. We even drove it from Manchester to Cornwall for our summer holiday (4 kids, 2 adults and luggage) with no problems. I eventualy part-exed it for a petrol Townie a couple of years ago. The Garage phoned me a few monthes after I had part-exed it telling me that the new owner had broken down on the M6 with a blown head gasket. Maybe the gasket was at fault for some time before it eventualy blew. It might be worth getting yours tested. HTH. Bill.

- (#7878) Bill, 15 Jan 04 15:52

May have an air lock. Once stopped the hot air expands and pushes the water into the expansion tank. Once cooled sucks it back. If some is pushed out the engine sucks more back in. Hence only filling the expansion bottle. Try a total drain down, flush with wynns flush or some such make, and refill with anti-freeze/distilled water mix. Fill it very slowly to minimise airlock, and with both heaters set to hot.
Hopes this cures it. Radiator and thermostat would be the next things to look at.

- (#7878) Clive (Bristol), 16 Jan 04 17:49