Morris Minor Owners Club

Hello again ,

A slight issue, which is the heater. When I tried to figure out what was going on this morning, along with the help of my dad, the hose leading from the engine to the heater isn't hot, after running the engine for about half an hour, and the valve is open. I suspect that it's an airblock, and if so, is there any way to remove it?

Take hose off the engine and hold it up high. Then fill the heater through the hose until the hose is full then replace hose onto engine. Run with the rad cap off for a couple of mins and that will shift an airlock. Otherwise it may be a blocked pipe or rad in which case you need to flush the system through to make sure water flows freely in all directions through the heater, engine block and rad..... Also check that you have a thermostat fitted and it is working....

Never ever had an airlock in this - but it could well be blocked with silt - and how do you KNOW the valve is open - does water come out if you remove the hose ? Only way to check. The hoses could also be kinked shut inside the car - where they connect to the heater.

I haven't removed the hose yet but I will do so and see if any water comes out, and if it does, I shall fill it up and replace it onto the engine, and then remove the radiator cap to remove the airlock if it is, although as bmcecosse pointed out it could be silt, so I shall check tomorrow perhaps, thank you .

Back flush with a garden hose to clear silt - but it could be blocked up valve (even though 'open') - or kinked hoses. look under the dash to check!

While you have the hose off look into the pipe from the valve to be sure it's clear of debris.
The cable operated ones can fail open or closed so it's probably worth poking something not to sharp (chop stick?) in there.
If it reaches to a depth half way into the thicker part without meeting resistance it should be clear enough to flow at least some water.

bmcecosse wrote:Back flush with a garden hose to clear silt - but it could be blocked up valve (even though 'open') - or kinked hoses. look under the dash to check!

I will have a check if I can get round to it, I also noticed that when it rains the cubby holes get damp and so does the passenger parcel shelf, I'll sort that out after I've got the heater done and dusted, thank you , and thank you everyone else, I needed the help .

If you're getting water into the gloveboxes/parcel shelf check the state of the windscreen rubber. Also check if the rubber washers under the windscreen wipers are in place/perished as this is another area water can leak into the glovebox area.

I would also add that the bonnet hinges can cause the same problem and on some cars the windscreen washer nozzle too - and check the hose for this is sound too.

Main water leak source is usually around the wiper spindle mountings - the rubber wedges can go hard and water can seep under.

Ok, I'll check when I can, of course it's safe not to at a time like this .
I noticed somewhere on this website it has diagrams of the heaters, so if I can I will try and get into the heater and see if anything has broken, and replace the gear stick gaiter as it is a problemchild of letting in cold air, too.

Thank you very much for the help everyone .

Very good plan to replace the gear stick gaiter, it lets in a lot of noise as well as draughts and fumes.

if the water pump blades have rusted away (or broken off if the water froze) then the symptoms can be similar to a blocked heater - the pump won't produce enough pressure to create flow in the heater.
The engine will get thermo-syphon flow which is probably enough in mid winter unless driven hard - however it will be much hotter than it should be.

Failed pump bades are much more likely if the car has been run on pure water for a polonged period.

rayofleamington wrote:if the water pump blades have rusted away (or broken off if the water froze) then the symptoms can be similar to a blocked heater - the pump won't produce enough pressure to create flow in the heater.
The engine will get thermo-syphon flow which is probably enough in mid winter unless driven hard - however it will be much hotter than it should be.

Failed pump bades are much more likely if the car has been run on pure water for a polonged period.

Ok, I'll check what the problem is at a later date, because it's not really the time to check at the moment .

I think it would require me taking the dashboard apart and replacing some parts of the heater, and the gaiter when I can get round to buying them .

Thank you very much everyone, I'll get round to it later on next year perhaps .

Good grief!
You can order parts and have them the next day.
I'm not aware of needing to take any of the dash apart to get to the heater and even if there is it's all inside the car.
Run an extension lead to an electric heater and get on with it