Heater Not Heating So Well

Not So Cosy

It is that time of the year where the temperatures outside are not of the overheated kind but the complete opposite! When it’s 5 Degrees C and the wind chill is 10 or more degrees colder fogging windows become a real issue!

My BA Falcon has a broken heater and so getting out in the mornings to hook up the trailer and head off to the first landscape job is trying at best! Out with the gloves and the jumper and hi-vis! A foggy window can only be cured with the air conditioner! Yes 2 degrees one morning and I have the AC on!

Read The Instructions

The BeaXT is much more comfortable on the cool mornings but the fan seemed a little  pathetic the other day so I decided that it may be time to pull the heater box apart and see what is going on. I have two concerns, one is that the heater core is blocked or faulty in some manner and the other that I have an electrical gremlin in the system!

XR XT Manual










So after removing the glove box, I start with the dismantling of the heater box and checking the wire connections. I have a copy of the workshop manual on my IPad and can see that the wires are actually wrong way around! The red one should be on the lower plug and the yellow on the other so that the dash switch is fully down on high fan speeds!

Next I can see that the slow speed is not working and that this is a resistor problem or failure of the switch! Since I have only just put the new heater switch in I don’t want to dismantle the switching gear again this year so we will have one speed!

Get To The Heart of the Problem.

Ok, wiring sorted now to check the core! Definitely heat in the heater box – I remove the front cover, with the foam seal, off the venting system. The foam falls to pieces – I remember fitting that more than 15 years ago! Will need to visit Clark Rubber and get a sheet of foam to make a new seal. The old board around the fan is showing it’s age so I carefully remove it and strap it up with some self-adhesive insulating tape. That should solve some of the air leaks around the fan too!

Remove the Glove Box!

I now have a look at the heater core and it is red hot on top where the hose is coming in and the core is quite warm but the air moving through is cool!? Now I am confused! Everything is indicating I should have warm air exiting the box but I don’t! In fact, some cool air is moving around the core!

Mmmmmm, seems a little dirty in here actually – what if……?

I get the Dyson and vacuum the core – yep dust is flying through the pipe and I can feel the air warming as it flys into the vacuum pipe! The problem is 20 years of dust gathered in the core plates and its enough to reduce the efficiency of the water to air heat exchange! I also install a foam insert behind the core so air cannot sneak around the back of it but has to run through the core!

Surface Deep

So seems all sorted now so I will address some of the surface rust in the vent outlet with rust converter and paint and cut out the new foam seals!

Wire brush, wipe with water and brush on rust converter!

A few hours later I can paint the converted rust surfaces, meanwhile …..

Manufacturing Time

A very simple task, draw around the vent and heater box cover/ vent tube onto the foam.

Cut enough foam off the sheet and draw!

Sharp scalpel blade and near perfect circle!

Sharp scalpel does the trick!

I put the foam on the cover and then draw around the outside of the cover to get the final cut!

Looking good – just draw around the top!

One more cut and I will be done!

Now that looks like it was factory!

In fact this is too perfect – a trial fit shows it sits perfectly – however foam will shrink over time and I really need it over size – so I cut a similar design from another thinner harder foam to put under the soft one! Works perfectly – should seal the air nicely into the vent!

I now need to add new foam to the cold air vent on the base of the cover – this has perished as well after such a long working life! I give it a clean up with the wire brush and a coat of paint and then using spray glue stick on new foam!

A coat of paint and new foam!

Rebuild Time

So everything is cleaned, treated for any rust, painted and repaired! Rebuilding the heater box is the next step!

Reinstalling the cold air vent flap!

The foam seals the base of the cold air vent column so that air is pushed more strongly through the heater box. In summer this is opened to let in cool air around your feet! No air conditioner  so this needs to be in good order for summer!

Like new!

Hook up the cover (this can be tricky the first time) by inserting the left edge into a slot along the box and hinging across the fan motor. Two screws hold it in place and the Bowden cable hooks onto the flap valve! A little adjustment and then lock the cable in place!

Looking good! I should have painted the cover!

Replace the glove box and no one knows what has been going on under the dash – except that it is toasty warm and we have windscreen de-misted!

Fairmont – you get a fan forced heater. Not like my HR Holden that had nothing!

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