Mark 2 heater woes

Got a 1962 Mark2. Heater output, both heat and fan assist is dismal.
Suggestions for upgrade?
Told that MG Metro motor and fan work well.

Wellcome to the forum Kondeeler.
Elementary advice but hopefully you are aware that the scuttle vent needs to be open
for best fan assist, also it`s worth bleeding the heater by setting a fast idle and disconnecting the top water hose at the heater box to expell a possible air lock.
Also check that the flap lever is free to move when you operate the control and likewise
the water control valve.
Peter B

Welcome to the forum, another thing to do is back flush the heater matrix,

You might also squeeze out a bit more heat if you changed from the standard 160F (70C) thermostat to a 180F one for winter use.,

Jaguar heaters were not that hot even when new (yes a pun) Was it Tom McCahill who described the Jag heater “like an old woman panting on your kneecap”
Granger has a range of 12 volt motors that can be substituted for the Lucas unit. Also skip the “low” speed resistor. I think someone put that into production as a joke.

Thinking outside the box , as I normally do :thinking:
A quick and easy fix would be a couple of fan heaters under the seats

It is possible to upgrade the heater significantly while retaining the sheet metal box structure and all the dash levers. In short, the fan motor is replaced and enhanced with electronic control. Here is a link to the first part of a 7-part instructional.

Many thanks to all for advice. Will try flushing heater matrix first.
Am I right in thinking the MG Metro motor and impeller are a direct (and cheaper) swap?

Some 15+ years ago I chose the Clayton upgraded heater box – in it’s infancy then but still offered I believe. A flap is fixed, box powder coated, uprated fan – most likely from something like a metro. Heat and output is fine but after recent works I’ve managed to do a poor job of the seals between box and bulkhead meaning some airflow escapes reducing the ‘blast’ internally. Another wee idea I employed was to block off one the vents to the rear of the cabin – taped over the under dash outlet – this diverts a little more air to the screen / front footwell as required. NB: Our car has a heated rear screen.

I’m about halfway through upgrading my heater with the kit from Clayton Classics. The kit came with a replacement heater matrix, larger fan and more powerful motor. You have to increase the size of the air inlet in the heater casing to accommodate the larger fan, there are also a few mods to the case to mount the motor and its bracket. That’s all completed and the case is away for painting. Here a few images:



Motor assy

Heater matrix

If I was to do a heater upgrade , I don’t think I would be spending as much cash as some of the so called heater upgrade kits , £300 plus ?
Looking at your heater Matrix phil , it looks just like a standard radiator core !
I had a uprated core fitted to my rad , standard has 27 rows , uprated 47 , that is a extra 20 rows of coolant open to the air to cool down .
In the heater box it would be more rows to let heat in ,
My first port of call would be a rad specialist to get the matrix upgraded .

If my fan heater did not work :grin:

Thanks for all the replies. Lots of ideas to ponder.
First I’m going to give the existing matrix a good flush out and check the integrity of the air ducts. If still not improved will look at upgrades.

Hi Ian, You’re right the heater core is simply a mini radiator, and most likely the main cause of poor performance in most cases. When I was driving my Jag (before I took it to bits) the heater wasn’t that bad, just slow to get going. However, my benchmark for poor heaters is Series Land Rovers! Lucky for me I got my Claytons kit from the Daimler Jaguar Spare parts club here in NZ, so wasn’t spending the amounts you mention :slight_smile:

Peter -
This looks like a good tip but can you please clarify? I have a new heater matrix and new valve so they should not be blocked. Engine is also recently rebuilt, rad re-cored and everything else working as it should. I think I have an air lock as getting next to no heat in the car. If I understand you I should unclip the upper (outlet) hose from the heater, start the engine and then reconnect when coolant is coming out?. Do I remove the radiator cap while doing this?
I presume that I start with a cold engine as I wouldn’t fancy removing the top heater hose when hot?.

Cold engine, heater on fully so valve is open, start it up, pull off the highest hose and reattach once there is coolant coming out. Water pump pressure will flush the air from the matrix and push it out. Once any air is out, reattach the hose. Then shut the engine off and add coolant if necessary. Shouldn’t take long. The cap can stay on.

Thanks David. I’ll give it a try at the weekend.

I think a big problem is the height of the heater matrix in relation to the filler neck .
As the MK2 has no expansion tank , the water system finds it’s own level , this is at the bottom of the filler neck , well below the outlet of the heater matrix outlet .
As water finds it’s own level I would guess the heater matrix would drop it’s level of water , and fill with air , in time :thinking: