C3 heater matrix

[mrmint]

Hi
What is the function of a heater matrix? Yes I guess it produces hot air into cabin is that it?
Br

[mrmint]

And does it contain coolant or just air?

[wheeler]

It should only have coolant in it, air in the heater matrix is not a good thing. Air is blown over the outside of it which directs hot air into the cabin.

[mrmint]

ok I will need to replace the heater matrix so then I will need to flush out all the coolat before I do the change then. Checking on pics on the heater matrix I could not see any coolat hoes going into it but maybe yes there are.
The pics I was looking at was an electrical heater matrix, but that is the same?

[wheeler]

No, some vehicles also have an electrical element heater too to give you hot air quicker till the coolant warms up.

[mrmint]

If the heater matrix is faulty can this cause that no hot air is blowing into the cabin even if I drive the car for 20 minutes, it is just blowing coldish. I have read in other section shere on this page that the heater matrix can cause that only cold air is blowing into cabin

[wheeler]

Yes it could but there are other things that could also cause this. Air trapped in it, a faulty water pump, a pipework blockage etc.

[mrmint]

Hi

I will try to flush the heater matrix and if that does not help maybe I will change it so to the question do I need to drain the whole coolant system or is the coolant going to the matrix a separate system so I can drain it when I disconnect the tubes from the actual matrix beneath the driver foot well. I guess I need to empty the whole system before
I have noted if you have a petrol engine you will have coolant in the matrix, on a diesel engine there is no coolant as it is electric.
BR

[GiveMeABreak]

No that's not correct. The electric elements are in most vehicles. They are basically an air heating resistor module, to help with quicker defrosting and heating of the cabin in colder conditions whilst the engine gets to temperature. These are separate and independent of the heater matrix.

As for the heater matrix, the coolant does not need draining, however you will need to depressurise the system and drain as much of the coolant from the matrix part beforehand to avoid extensive leaking into the car interior. This is usually done with an air gun, then clamping the engine side hoses afterwards.