Morris Minor Owners Club

Kevin,
Myself Mark and Dan not enbough evidence for you??

Hmmm, be surprised if they've rusted away completely.... Can imagine they are in a poor way though after changing one on a mk2 Astra I had & that was only 10 years old...

The pipes leading up to the heater seem to stay hot but maybe it's just silted up & the pump just can't drive it through at idle; i've got a new pump to go in when it gets a bit warmer anyway; guess I'll give the rad & heater a flush at the same time. Anyway had any experience of that halfords "Radflush" stuff??

The Bars stuff was the only stuff I found that made any difference - Sold in Halfords for about the same price.

Myself Mark and Dan not enbough evidence for you??

Ok Ray its conclusive then, I was not aware of Dans contribution.

On the subject of heaters.... I've put a sock in it.... & it works!

just in case you missed it Kevin..

KEVIN, use kettle descaler on the heater after flushing both
ways, easy enough to do,just disconnect both pipes from the
engine and tie them up to the bonnet cross bar so that they
are above the level of the heater. Fill until water runs out of
the pipe(a funnel is useful and put plastic over the distributor)
then lower one pipe into a bucket and blow like mad down the
other pipe until you have expelled the water. If mucky you should
see a large amount of discoloured water? repeat until it comes
out clean THEN reverse the process until that comes out clean
the other way. I did this once on an MGB and it took 32 flushes
to come out clean! Now is the time to refill the heater with
kettle descaler mixture and leave for as long as you like. You should
then get even more muck out. When satisfied fill both pipes
to the brim whilst they are above the heater level and quickly
reconnect to the engine to avoid an air lock.

SALTY MONK.. I would imagine that your poor flow at tickover
indicates a partial blockage in the heater piping. It is an awkward
job but if you remove the 1/2" bore rubber heater return pipe and
extend it so that it will reach the radiator cap,then block the
metal pipe from which you removed the hose. you can start the
engine and,at tickover, you should see a healthy steady flow
of water into the open radiator. if it is a miserable trickle which
hardly improves when you rev up then you have a blockage.
I have seen a blockage in the heater on/off tap at the rear of
the cylinder head and also in the heater matrix itself where
bits of 'clag' had all but stopped the flow.

It is an awkward
job but if you remove the 1/2" bore rubber heater return pipe and
extend it so that it will reach the radiator cap,then block the
metal pipe from which you removed the hose. you can start the
engine and,at tickover, you should see a healthy steady flow
of water into the open radiator

That's the method I tried when my waterpump was faulty - The flow was ok (although less than it should be - difficult when you don't have a back to back check to see what is normal) However if the end of the pipe was raised 6" from the radiator level, the bad pump couldn't push the fluid up it.
With the new pump, it would push a lot further up (but unfortunately I didn't measure it to say what a good one can do)

As you're changing the pump anyway - you'll find out what the old one was like. Whilst it's all apart it's well worth to reverse flush the heater, as recommended already AND the radiator. I ran the hose through mine for 15 minutes each way, repeating about half a dozen times until it was permanently clear.

Right so disconnect the pipe at the bulkhead to allow some air flow and block the pipe with a sock, when I get a chance I will give it a go

Right so disconnect the pipe at the bulkhead to allow some air flow and block the pipe with a sock, when I get a chance I will give it a go

Nope - disconnect the air pipe at the heater to allow it to take internal air, and also block the pipe to prevent a flood of cold air into the car when driving at speed.

Thanks Ray I will also make sure my heads screwed on the right direction as well which it does not seem to be at the moment

I promise this is my last comment on fitting the 'last'type
Minor heater to my early convertible. I went for a ride today
with the roof off and found that despite being chilly around
the head area my legs and feet were perfectly comfortable with the warmth from the heater with NO FRESH AIR inlet
connected( which,of course, means that the fan must be 'on'
to obtain any throughflow). I would recommend this system to
anyone who is 'too cold'. I will probably try fitting the early
type rheostat next so that I can vary the fan speed at will.

Re the above, tried the Rheostat today and it works a treat. The
fan speed is controllable right down to a very slow speed, BUT,
being a resistor it gets very hot so would have to be sited in a
safe place (it will not fit in place of the standard toggle switch).

Clip a heat sink to it and make sure it extends into the path of the air from the fan. An idea, no?

A perfectly sound idea Mr A but I have decided to put up with
the normal full speed fan noise at the moment because, to fit the
Variable control I would have to take the heater apart and it was
such a pig to retro fit that I can't face it at the moment. Did you
check your heater motor polarity?? Or am I mixing you up with
another Minor nut?

Not me! I'm still runnig +ve earth

Been away for a few days (retrieving dummy?) and no access to a p.c.
I'm the "nut" Willie, no not checked yet, it's one of those work up the enthusiasm things because my radio is installed left of heater and blocks access considerably - that's probably why never noticed connections in past. But will do somewhere along the way - honest.

Good, I am looking forward to your posting when you announce
that the fan is now twice as fast!!

Yes, just in time for the warmer? weather!!