Morris Minor Owners Club

Are these heaters any good? Little or no heat coming out of mine, i thought of airlocks so i re-routed outlet hose so no high spots, Fan works ok. How can i check if heater is worth keeping or is it better to fit a later one ?

Reports of effectiveness vary, but start by thoroughly flushing the system and making sure that the heater control tap on top of the block is open.

If the heater is getting hot, but not blowing air (even with fan running) then check that the intake flap is open and that the matrix is not blocked by dust and fluff etc.

They're fine if working right. There's no intake flap though, so don't spend too much time looking for that - it's a recirculating heater (if car is a late948 then it may have a fresh air inlet close to, but not connected to, the heater, but this won't affect heat output).

I have a round smiths heater on one of mine and it has a shroud round the heater with a duct leading to an oblong hole cut in the floor behind the gearbox belhousing with a flap operated by a cable next to the heater.

Yes, that's the 'fresh air' duct they fitted to later 948 cars - pull the knob out to open the duct. It won't stop the heater from working if it's blocked though, as you get next to no ram effect from it. I suspect it's either a gummed up matrix, or a blockage coming out of the head, maybe in the tap. Need to check whether the hoses get hot, and bear in mind that without the fan on, you'll get next to no output out of the heater.

Or too low setting thermostat (go 88 in winter) and very possible the heater water valve not fully open or chocked with crud. Take it off and inspect for full bore - and check the port in the head too.

The fug stirrer heater is controlled by a rheostat switch which can be carefully dismantled and cleaned.