Heater not working -- airlocked?

[Paul Fraser]

Took off the engine manifold hose to get at the oil pressure sender and now the heater isn't working. Have already massaged the hoses I can get to and left the top off the reservoir but the heater still doesn't work. This even after the system belched a heap of air and water out of the reservoir...
Am I missing a simpler solution...?

 

[Riverside]

I guess from your description you haven't bled the coolant:

Set the heater to full heat (doesn't matter where the air goes or fan speed, just point he temp knob to the red blob).
Start the engine & allow it to fully warm up & pressurise at idle (once the radiator fan has come on you know the thermostat will be fully open).
Switch off the engine & carefully crack open the coolant bleed screw on the small casting where the top hose meets the head with (iirc) a 12mm spanner and wait until the coolant seeping out is just water with no bubbles. You can usually tell because it goes quiet.
Nip the bleed screw back up, wait to cool & top up the coolant if needed, then repeat to check you got all the air out.

It can help to have the car on a gently up-hill slope when you do this to make sure the bleed screw is the highest point in the system but a level surface should be fine, just don't have the car pointing downhill.

Best to locate the bleed screw & check you can easily free it off while the car is cold, if it's tight when you first try to open it you may open it too far. Best to have a clean rag just under it too so you can easily see the coolant when it starts to emerge.

hth

 

[Paul Fraser]

Thanks a lot for that -- I'll try this tomorrow.

 

[Paul Fraser]

I have heat!! Finally got it done after a false start. You have to wait until the fan kicks in otherwise you just don't get the pressure to bleed it do you? First time I opened the valve, nothing, as not hot enough.
Did about three bleeds and put in a litre of water.
Thanks a lot.

 

[Riverside]

ORIGINAL: Paul Fraser
You have to wait until the fan kicks in otherwise you just don't get the pressure to bleed it do you?

Spot on, it's not too difficult once you've done it a few times, I keep a 12mm spanner in the car & check the coolant for air regularly, I think mine has a tiny leak somewhere & I can occasionally hear the water surging through the heater pipes so next time I stop & just give it a quick bleed & it keeps the cooling system quiet.

I've had a few problems with the cooling on my car (replaced thermostat, water pump, bottom hose over the winter) so I'm a bit obsessive over it now []

 

[Paul Fraser]

ORIGINAL: Riverside
I've had a few problems with the cooling on my car (replaced thermostat, water pump, bottom hose over the winter) so I'm a bit obsessive over it now []

I'll consider myself lucky just having a bit of air then...