Astra H 1.7 diesel.

Heater was working fine yesterday.
Today, it’s chuffing cold.

The fan with still blow at 4 different speeds but the temperature dial makes no difference.

Any ideas? Any chance it might be a quick easy fix?

Cheers.

Low coolant level?

air lock ,water leak, take of rad cap and squeezed big black pipe, fill with water.

In a Fiesta the heat setting works a leccy thingy in the pipe to the heater. This sometimes sulks and sticks and has to be replaced.

Turn it off and on again?

+1 for low coolant, meaning you probably have a coolant leak somewhere.

Just had a known about coolant leak in my car fixed, but while I’d been running it and topping it up another larger leak had developed which was dumping much more coolant. First inkling something was up, was when the heater stopped heating. Checked coolant bootle and completely empty…..

Check if the floor carpets are wet, if so its either the heater matrix or a broken pipe, either one a pain to fix.

When you change the fan power can you feel a difference in the amount of air coming out? If not, might be clogged pollen filters. Just take ’em out and bin ’em.

Alternatively, is the engine temp getting up to normal? If not maybe a thermostat change required.

If neither, check coolant level.

It could be a clogged heater pipe too, depends on age of vehicle. Can normally flush through with a hosepipe if you know what you are doing.

as last post, but check coolant level and for leaks first, including inside the vehicle ie footwell, then check other stuff. first will lead to engine blowing up, all the rest just means you get cold.

Managed to check it out before I left work. Coolant was pretty much empty. Topped it up and heating now works. Coolant empty 40 miles later. Found one split hose, one on its way out. Must have suddenly let go.

its an astra, 1 can of petrol and a match should sort it.

Did you not read the op? It’s a diesel.