I need a bit of clarification on my cooling system.

[Chipper]

I have had huge cooling system problems of recent which i think i have now sorted out, my plastic thermostat housing went bad and caused a huge airlock/overheat, after replacing the thermostat housing the car ran cold so i replaced the thermostat as well and now I get coolant low warnings when the level is fine so I think the overheat fried a few thimgs, but not my head gasket thank god. the coolant level sensor is cheap to replace and I will be dong it next weekend

The situiation i have now is that everything works fine apart from at low speeds i have cold air from the heater althought it is set to hot, works fine if I'm cruising the motorway (70-90MPH) but at low speed is cold.

I'm presuming this is due to a broken aux water pump, it has been making a lot of noise recently and now its quiet so i'm presuming its given up.

Just wanted a second opinion.

Cheers

[stu1]

Are you only getting the coolant low warning when the engine is warmed up?

If so, it's worth check the coolant level when hot. If it is actually low I'd say you still possibly have an airlock.

[henry161]

Did you bleed the radiator ? Mine blows out cold air at idle when the rad has some air in it. There should be a bleed bolt on top of the rad which you open up when the engine is hot and running - close it when there are no more bubbles coming out.

[Chipper]

yep already gone thru a seriuos bleeding process, including blowing down on the expansion tank until water is folwing freely out of the bleed screw on top of the radiator, with the heater on hot. I am am fairly certain i have bleed properly!

[632 Regal]

pretty much sounds like the aux pump, when mine went it popped internally and I didnt know til I stopped in my driveway...how lucky.

[danzee]

Yes, it's the aux pump.
About $80 as I recall.
Not a bad job. Procedure is posted.
Two needle nose vise grips are good to have to pinch off the hoses.
Z