Cabin heater issues

[Ignis]

Hello everyone,

I've got an issue with my cabin heater and would appreciate your advice.

The heater would only blow very hot air at 32C, 0.5C less and it will be just warm and it will stay warm no matter what you do till you get to about 19C, when it blows cool air. The ventilator works fine, different modes too. It all started very unexpectedly after I had had issues with cooling system hoses, which were since replaced, but the heater now doesn't work properly.

My local garage which I usually use for MOT and minor things say they have no software for Mazda Bongo so cannot trace the error...

In case it matters, she is a 2.5 V6 petrol 2001.

Thank you!!

[Bob]

First question has to be, 'Was it bled properly?'

Were the hoses fitted by your local garage or a Bongo Savvy one?

[Ignis]

Well, I can only guess, whether it was bled properly or not, but I've used this particular garage for the past four years, they are quite reputable in Central London and honest. So I'd hope...

[Bongolia]

Hello everyone,

I've got an issue with my cabin heater and would appreciate your advice.

The heater would only blow very hot air at 32C, 0.5C less and it will be just warm and it will stay warm no matter what you do till you get to about 19C, when it blows cool air. The ventilator works fine, different modes too. It all started very unexpectedly after I had had issues with cooling system hoses, which were since replaced, but the heater now doesn't work properly.

My local garage which I usually use for MOT and minor things say they have no software for Mazda Bongo so cannot trace the error...

In case it matters, she is a 2.5 V6 petrol 2001.

Thank you!!

Hi Ignis.
I too would be interested in the solution to this as I have exactly the same issue on my 2.0 ltr.
I dont believe it is coolant related more likely a temp sensor. I haven't had the time to look into it and the weather being as it is its not a problem.
I am wondering is your rear heater is affected like the front one?
On my vehicle the rear heater is not connected so I cannot check.

[Ignis]

Hi Ignis.
I too would be interested in the solution to this as I have exactly the same issue on my 2.0 ltr.
I dont believe it is coolant related more likely a temp sensor. I haven't had the time to look into it and the weather being as it is its not a problem.
I am wondering is your rear heater is affected like the front one?
On my vehicle the rear heater is not connected so I cannot check.

Hi Bongolia,

Good to know I am not the only one affected.
Unfortunately, I've also requested my rear heater bypassed, as I have no vents to blow air at the back anyway. The guy in the garage (but they don't routinely service Bongos!) mentioned that if it was a thermostat, it could be quite costly...

[Bob]

The 2 ltr is quite a different beast, the cooling system is self bleeding so much simpler.

[Ignis]

The 2 ltr is quite a different beast, the cooling system is self bleeding so much simpler.

Wow, that's an interesting twist!

[g8dhe]

The amount of piping and risk of a leak is just the same however! Its simpler to bleed, yes not a simpler system!

[Bongolia]

The 2 ltr is quite a different beast, the cooling system is self bleeding so much simpler.

Setting aside the difference in the cooling system scheme is the heat regulation method the same on both Geoff?
Is there a thermal sensor to control the pitch of the vents or some device like that?

[g8dhe]

Yes identical, the heating matrix (front and rear) are always ON there is no valve, the heat mixing is accomplished on the hot air side with a vane to allow the hot air into the airstream. So from a engine cooling point of view it makes very little difference, but you can identify that heat is getting into the matrix and its not blocked with either an airlock or silt in the tubes.

[Bongolia]

Yes identical, the heating matrix (front and rear) are always ON there is no valve, the heat mixing is accomplished on the hot air side with a vane to allow the hot air into the airstream. So from a engine cooling point of view it makes very little difference, but you can identify that heat is getting into the matrix and its not blocked with either an airlock or silt in the tubes.

I did check and the heater pipes are both hot, so there must be a thermostat of some sort somewhere in the system, anyone know where and a method to check it?

[g8dhe]

The only thermostat is the one for controlling the flow from the radiator back to the engine, its located at the front nearside.

[Bongolia]

So how is the heater temperature regulated?

[g8dhe]

By the vane in the air box that opens up by a servo in the passenger footwell allowing heated air into the stream, the is another servo on the drivers foot well that directs the air stream to the vents selected.

[Bongolia]

Right, I think I may be a on different page here.

Ignis, is your vehicle fitted with the automatic AC panel that gives a digital read out or do you select fan speed via a rotary knob?