Heater Question 88 series IIa

[Arrington]

Hello everyone,

I have a question about the heaters in the old series IIA. I see the air inlet on the front grill which brings in very cold air and goes thru the fan and then thru heater core into cabin. But am I lost here, we are wanting heat? Cold outside air for heat? Why not use a high rpm fan? Why not pull air from cabin to go into heater?

I have seen guys use a $20.00 tool box from walmart and a heater core from a 70 chevy pickup that produces 3 times the heat a rover makes.

Just curious if anyone could help explain this to me.

[o2batsea]

Series Rovers came with a variety of heaters, from the round Smith's "shin burner" to the Kodiak. Some draw outside air, some don't.

I haven't noticed a difference between recirculated air and outside air, except to say that the hole-in-the-wing design has it's drawbacks.
Maybe outside air, being cold, is less humid that recirculated air full of hot breath and farts.

[TedW]

I believe that Smith's refers to their system as a "Fresh Air" heater (corrections welcomed).

The system on my 1970 IIA works fine, and pumps out lots of heat - thanks, I believe, to a clean heater core and a new squirrel wheel motor.

I notice that the defroster in my Infiniti (and in every other car I've owned) only works with fresh air from the outside - it won't work on recirculate. Given that, I suppose it makes sense that the very rudimentary Rover system will have one setting for everything - and that's fresh air from outside.

[TeriAnn]

Hello everyone,

I have a question about the heaters in the old series IIA. I see the air inlet on the front grill which brings in very cold air and goes thru the fan and then thru heater core into cabin.

With the intake on the radiator bulkhead what you have is a Kodiak Mk II heater. Which was only made a couple years.

The Kodiak heater is a North American only dealer installed option and is a fresh air heater design.

Cold outside air is less humid than warm inside air. With people respiring, recirculating heaters tend to have moisture build up which results in condensation on all cool surfaces, esp the glass.

Fresh air heaters tend to keep the moisture down which minimizes window fogging.

Kodiaks work pretty well as long as you have a clean heater core, a 180 degree thermostat & warm engine. The fans throw a lot of air if they are in good condition and the air pathways are clear. You can close the air path before the fan and at the vents inside the truck Check to see that there are wide open. Also there is a coolant control valve in the line going to the heater core. It needs to be fully open and unclogged for full flow. Early on I tossed the air valve going into the fan and the coolant control valve on my Kodiak MK III just to maximize flow.

The motor is single speed but the switch is dual speed with a resister to lower the voltage for the low speed position. Be sure you have the switch pulled out to high speed mode.


Of course all bets are off if the interior panels are stripped out of the truck and you have lousy fitting doors and/or poor seals. No car heater will compensate for a drafty uninsulated truck when it is freezing outside.

[Arrington]

Thanks TeriAnn,

My blower motor may be kinda weak. Can you still get blower motors for these units?

[yorker]

With the intake on the radiator bulkhead what you have is a Kodiak Mk II heater. Which was only made a couple year

Mark IVs had intakes that went under the battery to the radiator panel too. The theory was that you are getting air circulating from the momentum of the vehicle, even when the blower isn't going, unless you've closed the valve in the duct work. Thus if you are driving 45mph you are getting 45mph worth of cold dry air entering the heating system before you even consider the suction of the fan.

[artpeck]

One cannot stress enough the need for a clean unrestricted core for the heater to produce (more than) adequate heat. Mine didn't and the core didn't come clean until I ran a hose with a nipple on the end into one side of the core finally flushing out sludge and crap from the other side. Took 15-20 minutes of flushing in both directions to get a clear unimpeded flow and with that, lots of heat. I had already flushed the radiator and block but this apparently had zero impact on the core itself.

Having said that I am in northern California but it still gets below freezing and now the cabin is more than warm enough after the engine heats up.

[dreamin88s]

I too have a weak motor,UK folks have been installing defender blowers and seem very happy,not sure if there is a difference in mounts as there's are RHD

[Arrington]

I appreciate the info, Thanks