[Jarlef]

Yesterday I discover that the cabin heater is not working. It blows cold air only. The air condition is working just fine and the engine temperature is normal
My first thought was the thermostat was malfunctioning and prevented coolant to flow through the cabin heater. I removed the thermostat but the heater still blows cold air

I have discover yellow foam in the expansion tank, which is not good. I believe it may be due to mixing of different types of coolant, or it may be rust and dirt, due to the coolant cleaner I added. I used the red long life type coolant. I've drained the system and I now in the cleaning witch tapwater prosess. I am planning to flush and drain once more before refilling long life coolant. Unfortunately I don't believe this will solve the problem

Is there any way to check if the coolant is flowing through the cabin heather?
Is there any way to prevent air-pockets?

At last I planning to look at the heater electrical system. I don't not much about it, except for checking fuses.

Any good advices on how to fix it?

[Asterix]

There's 2 coolant hoses entering the cabin from the engine compartment, they should both be warm if you have flow through the heater.

The water always flows through the cabin heater. When you change between cold and hot air it's a flap directing the airflow either through the heating element or beside it. The fault could be the small electric motor not working.

[Jarlef]

There's 2 coolant hoses entering the cabin from the engine compartment, they should both be warm if you have flow through the heater.

The water always flows through the cabin heater. When you change between cold and hot air it's a flap directing the airflow either through the heating element or beside it. The fault could be the small electric motor not working.

Thanks.
I found some really hot pipe deep under the steering wheel, near the floor, and the two hose entering the cabin is quite hot, but not "burning hot"
I will look at the airflow flap tomorrow. I believe it may be the problem...

[Phil №❶]

I hope you have good coolant flow through your engine 

When changing coolant, you need to keep an eye on the level for approx 3 weeks to top up from air bubbles.

[Jarlef]

I still haven't found the problem. What else could I do?

I have changed coolant and thermostat and everything seems to be in order.
I have checked every fuses, all working... I have not checked relays. Which relays should I check?

I don't know how to check the air direction flap is working. How to do that?

I found a possible inside the cabin. It is not much. Could this be a problem?

[Paolo5]

Hi Jarlef,
Did this problem start before or after you changed any coolant?

Are both radiator hoses hot after the temperature gauge gets to operating temperature? One hose gets hot quickly and the other one only gets hot once the thermostat opens, allowing hot water through.


I have a 2010 diesel and the temperature gauge shows normal operating temperature when the water temperature is only at 60C. The gauge shows the same temperature (just below half-way) when actual operating temperature of 88C (or so) is attained.

What I am trying to say is that the gauge may show operating temperature but it may actually be much less!

Cheers,
Paolo

[Jarlef]

I finally found out that the Heater Flap Actuator is not working. Still don't know why.
When I manually move the flap, the cabin heater blows hot-air.

It took me quite some time to figure out how to remove the glowbox. If you know how it should take about 10 minutes...

Thanks for the help so far. I'll keep you posted