I changed the coolant in the supe over the weekend. Having filled it with new coolant, the heater in the cabin no longer puts out any warm air, just cold air. I guess it's either an airlock in the matrix or an actual blocked matrix (shudder). Before changing the coolant, the heater used to get warm but not really hot.
The coolant temp gauge reads normal under any type of driving (idling, cruising, spirited driving). I've tried squeezing the radiator hoses, but that doesn't seem to have helped. The coolant level in the expansion bottle is going down each day after driving, which I hope is air coming out the system and not a leak!
The top rad hose gets hot when the engine is up to temperature, but the bottom hose barely gets warm at all: after driving for about half an hour, I turned off the engine and could hold the bottom hose indefinitely: I know this is the cool return hose, but I would have thought it would be a bit warmer than this.
So, what's the best way of removing an airlock from the heater? I've tried the upturned powerade bottle in the rad cap hole, but 1) after idling for 20 mins, the coolant level was hardly increasing up the bottle, and 2) despite my best efforts, coolant leaked out around the bottle/rad interface.
I've tried squeezing the hoses. Do I need to drain the coolant back out and re-fill, and hope for the best?