Fixed Multiple Issues But Still Blowing Cold Air?
 

Still no hot air after each of these fixes.

Temperature gauge was going most of the way up but not reaching the centre of the dial so I changed the thermostat and now it is going to the middle and staying there.

I've changed the pollen filter.
Flushed the system.
Recalibrated the CCM with Vida.

Any ideas?

Hi.
The heater matrix is a full-flow system so the hot water circulates continuously. If there is no hot water then there is no heat. So an issue
with the water pump ( low impetus) is a possibility. Most likely is an air-lock or a blockage in the lines from the pump or the matrix itself is blocked.
Remove the under glove-box trim again and with the engine running and fully up to temperature feel the two rubber bulkhead hoses and aluminium pipes that go to/from the matrix.
They should both be hot to roughly the same temp. If one is hot (latent heat)and the other cold then the matrix is restricted. If both are cold then the problem lies in the lines to the matrix.

A radiator "leak-stop" product can clog a heater core completely.

A grey putty like compound did so in a family member's car.

After disconnecting the system hoses I used scraps of hose and a funnel to coax various cleaners into the core

Gasoline was the only solvent which worked.

Thanks guys!

I will check this this evening an let you konw.

heater
 

are your heater pipes actually attached to the matrix and not by passed? if they are by passed you wouldn't get any heat any way.

If a heater matrix leaked I could MAYBE see someone bypassing it as the cheapest "fix" possible...but that's a big maybe.

Who would do that?

I checked the pipes and the bottom one is definitely hotter than the top one, so it looks like it's a blocked heater matrix.

I have a new one ordered, so will replace and let you know.

Fingers crossed it fixes it.

That's 3/3 of the Volvos I've owned which have had heater matrix problems ffs!

"I checked the pipes and the bottom one is definitely hotter than the top one"
Hi.
If the top pipe is cold then there is no flow so the matrix is probably blocked.
If there is heat in both pipes then there is flow. It could just be the heat control flap is not working.
I did say that both pipes should be roughly the same temp. This would be with the heater fan off and the controls set to cold.
With the heater set to max and the blower on the matrix should give up its heat and the temp difference in the pipes more noticeable.
As changing the matrix is a pig of a job I would have disconnected the bulkhead hose fittings, attached a hose and back flushed the matrix in both directions. Then check the heater flap operation.

Great advice, thanks! I'll back flush it this evening.

The heater flaps seem to be working fine, as I can hear the motors operating when I turn the temperature control from hot to cold.

Hi.
Yeah. The motors might be working but are they operating the flaps?
Motors 7 & 8 are the left and right heater flap , and 6 is ventilation.