Morris Minor Owners Club

help please i have a 1965 morris i have put a new thermostat in and to new hoses to the heater but the heater is not blowing very hot air in the car. thanks ian

Possibly your tap (on the cylinder head) is partially blocked (closed or clogged up.)

Are both the heater pipes getting hot?
Is your engine getting hot enough, that is , is your hose hot at the bottom of the rad?

Is the fan blowing? Is the fresh air trunk connected correctly? What value of thermostat did you fit - should be 88 or even 92 for winter running. And yes - valve or outlet from head blocked with crud is worth checking.

, is your hose hot at the bottom of the rad?[/quote]
The bottom hose should not be hot

Did you flush the heater matrix out?? May be silted up if you live in a hard water area.

And, check the new hoses are not kinked!

Take the rubber pipes off where they join the engine, and flush out the heater with a hose in both directions. Top up with toilet descaler and leave overnight. Flush again next morning several times. Check inside the car for any leaks then refil heater pipes with water/antifreeze mixture.

In my experience - this is completely NORMAL at this time of year.
Of course, make sure heater tap is open. The heater matrix isn't very efficient and is much less efficient when it is old and clogged up. Flushing can help a lot but not always enough.

After checking heater tap and flushing the heater...
To improve cabin heat in Winter, disconnect both ends of the heater air inlet trunking (big convoluted pipe) and block the trunking to prevent cold air being forced in. A handful of carrier bags makes an (easily removable) block in the pipe.

This allows the heater to pick up warmer air from inside the vehicle and you get much improved cabin temperature.
The downside is that if the screen mists up you will need to open a quarterlight window to help reduce the humidity in the cabin. Close it again when the misting has reduced enough, and stay warm.

If you relocate the intake of the trunk to behind the radiator -at the top - it works very much better. But if there are fumes in the engine compartment you will get them in the cab........

rayofleamington wrote:In my experience - this is completely NORMAL at this time of year.
-snip-

Might be for your cars Ray but mine both have toasty heaters! It IS possible if everything is working well to keep warm in the winter in a Minor. ALso, make sure all door seals are present and good etc.

Not only the door seals, the gear lever gaiter and there should be a foam pad that seals where the clutch pedal meets the floor.
Otherwise you get a draught right up your trouser leg!

Might be for your cars Ray but mine both have toasty heaters!

I've had a few that were just about 'ok'. Most memorable was one with an aftermarket gold round heater (the one with opening flaps on it) with no fresh air intake, and one or 2 with standard heaters.

The only one I've had that was 'toasty' was a 1098 that had a full engine rebuild - the extra engine heat during running in December and January was really put to good use.

Most of the Minor 100's I've had were a bit less than ok, despite flushing the heater. Generally messing with the old crusty heater
tap leads to a leak and then a replacement of it. Some of the replacement (new) cable operated taps don't open properly etc... At that point I just wear more clothes. In some of them I've needed to wear double jumper and gloves

If in doubt - get rid of the tap and just fit a simple stub pipe with full bore. For best heater action the bypass hose needs to be eliminated or blocked off. The difference is amazing - and the warm up time for the heater is much shorter.

A BIG THANKS TO ALLTHE MORRIS MINOR CLUB HELP IAN