Heater barely getting warm!

[Jsg118]

Hi everyone.
I've recently got a Bx you might know back on the road after a few years standing, J119 GCR. All is going well so far bar the heater! and I can't work it out! It doesn't get hot at all. So far I've flushed the cooling system with new coolant maybe 3 times, flushed the heater pipes and matrix with a hose (all seemed to flow ok), installed a new thermostat, and removed and cleaned the heater valve. I've also spent hours trying to make sure its bled entirely filling the system completely, heater on, and front of the car jacked up, cap off until the fans come on and it still won't get hot. the only thing I can think of is that there is an airlock in the matrix? It's a 1991 TZD turbo. If anyone has any suggestions it would be very much appreciated! Cheers! Jake.

[Jaba]

A few random thoughts.
Is the heater valve actually opening with the temperature knob. Hot water should come in and go out if the blower is off.
As the water pump is what drives the water through what condition is it in.
There is an air blending system of some sort are the flaps moving to prevent air flow bypassing the matrix. Also is the matrix allowing air to pass through it.
Are the heater hoses connected correctly - although it should still work in reverse flow.

What a mare when you need a heater in a cold winter.

[xantia_v6]

[Jsg118]

A few random thoughts.
Is the heater valve actually opening with the temperature knob. Hot water should come in and go out if the blower is off.
As the water pump is what drives the water through what condition is it in.
There is an air blending system of some sort are the flaps moving to prevent air flow bypassing the matrix. Also is the matrix allowing air to pass through it.
Are the heater hoses connected correctly - although it should still work in reverse flow.

What a mare when you need a heater in a cold winter.

Thats an idea! I’m not 100% sure on how the airflow is directed but there is a flap which is connected to the heater valve. I guess this is the blender between cold air and air that passes through the matrix. When this is disconnected from the valve and moved manually, it seems to either make the air absolutely freezing or completely block the flow altogether. Would this indicate that the air flow through the matrix is being blocked by something or does anyone know if this is how it should be?

As for the other things, I believe the water pump was replaced recently. The black solid plastic pipes attached to the matrix do get reasonably hot to the touch so there must be some coolant flowing. I’m not sure which the right way is for the hoses but the bottom hose on the bulkhead goes to the gearbox side of the rear of the engine.

I’ll have to do some more experimenting. I might try and take the fan housing off and see if I can get a vac down to the back of the matrix. If not I’ll wait for some better weather and try and take it out altogether

The lever in blue is the flap that seems to restrict the airflow on mine

[Jaba]

With the heater blower box removed I think you can just see the matrix and this could conceivably be blocked by something. On some cars there is also a flap closing off or restricting air coming into car. These can rust up and stop moving too. There is also a thermostat bypass hose from the thermo housing allowing hot water to the heater before the stat has opened. Its a metal pipe on petrol cars with a bleed screw on it.

For your problem it is like the heater valve does not open, there is no sufficient hot water flow through the matrix or no air is passing through the hot matrix.
I have always found the BX heater to be very good. It must be fixable.