MGB Register Forum

Took the car (Mk1 1967) for its first winter run a couple of weeks ago-London to Winchester and back- since buying it in the summer. No heat-not even luke warm. Ambient temp about +5c . Temp guage showing 75-80c. Fresh air flap closed. Heater flaps open. Fan working. Diverter knob changes from demisters to footwell ok and blasting cold air. Heater valve opens and closes full travel (replaced 1998). I think the previous owner did not use the car in winter. Fluid in rad header tank clean and clear. I read somewhere about possibility of an airlock. I am thinking of starting by disconnecting the heater hoses and back flushing the heater element. Is this a good place to start? Any ideas on the best order to go about investigating this?

First things first - have you got hot water flowing in the heater hoses? Both into the heater and back out again? If you haven't, I would just link the two with a length of hose and see if the hot water flows through that.
You can then determine whether it might be a blocked heater or a blocked tap.

Ian F

Ian
Thanks. That is a good way to start. I'll give it a go.

Can you keep us up to date on this one Alan. I have a similar problem.
Thanks, Dave

quick tip - feel the hoses to and from the heater matrix (under the bonnet) when the engine is good and warm. They should both be hot. Mine weren't because the heater control valve on the side of the engine block was full of crud and blocked. Replaced for under £20 and now its as warm as toast.

Gary

Thanks for your responses.

Took the car for a run yesterday to get it up to temperature and feel the hoses etc as suggested. But... suddenly the heater has started to work. Not super hot, but definitely warm where before there was nothing. We will not be using the car much during the winter so I think that part of the spring clean will be disconnecting the heater hoses and flushing through and perhaps changing the heater valve.
Now is the winter of our discontent made glorious summer (well not quite!)
Alan