[whisk]

Hi all, can any one give me some advice please. The heater takes a while to get warm in the cabin and then goes from warm to cold on it's own.[scratch]

 

[deadend9009]

How miles on your car? It is a diesel, so it should take a bit to get warm. Try replacing the engine thermostat, if it is stuck open, you'll get very little heat to the cabin.

 

[sailor]

There is a door in the HVAC unit which controls how much warm & cold air comes into the cabin.

The actuator for that can quit working properly, so there isn't appropriate temperature control.

On US cars, it's behind the glove box (Right hand side), access on yours MIGHT be above & to the left of the steering column if the parts are the same...

looking for an actuator that moves a lever to control the warm & cold air blend is the most likely issue... since the heater gets warm water all the time & just mixes cold air & warm to control temp..

Luck!

 

[Grumpy]

Have you checked the coolant level. Low coolant level with the associated air in the system could cause this, it seems to me.

 

[sailor]

Absolutely!

(Hi Grumpy!)

 

[whynotthinkwhynot]

I was about to mention coolant level- diesels run cold as it is anyway, so an owner might not notice low coolant in the summer.