Morris Minor Owners Club

Over the last few days I've found that the radiator is occasionally overflowing slightly and was producing a bit of steam after a run today, the car generally seems to be running fine though. Whats the likely problem causing it to overheat so easily?
Thanks

Faulty thermostat?

Blocked tubes, get it flushed out

I'd go with thermostat myself ... take it out and drop it into a pan of boiling water ... if it doesn't open then it's stuffed & you need a new one.

If your thermostat cover is seized onto the threads it's mounted on then you can try putting two nuts on the end of a thread & tightening them against each other - you can then wind the thread out of the block ... if you don't have any nuts thin enough to get two on there then try tapping it from the side to loosen the crud that collects from the reaction between the steel threads & the white-metal casting of the cover.

Failing that get a new thermostat cover and hit the old one with a cold chisel until it breaks into pieces!

Put plenty of copper-ease on the threads when you re-assemble it ;)

Thermostats are deadly reliable in my experience - flush the cooling system out as the first action........and don't fill the rad right to the top - and perhaps treat it to a new rad cap ?