Avensis D4D 2.0 Diesel

[Paul Hutchinson]

When driving heater blows warm/hot air OK but when idling it blows cold air without changing control settings,anyone had the same problem? Have been told it could be an airlock,have tried running with radiator cap off to allow air to escape-no change.Car runs perfectly otherwise.

[PaulinhoT]

Hi Paul, welcome into the TOC, have you tried squeezing the bottom hoses with the rad cap off ?

[Paul Hutchinson]

Hi Paul thanks for the advice but i tried that while it was warming up,it made no difference.I am wondering if it is the volume of water running through the heater matrix at idle the flow will be less than while driving.I am thinking of trying a chemical flush followed by a fresh water flush to shift any sediment, with the matrix being a slow spot in the system. Can you or anyone else recomend anything else. Havent tried one before can you recomend one?

[dervdave]

Airlock in heater

Thermostat stuck open (does it take a while to warm ?)

Waterpump on the way out

[acetip]

Welcome Paul and welcome. Is your engine getting up to temp ok.

[Paul Hutchinson]

Thanks Dave & Peter i dont think its the thermostat engine gets to temp ok and stays there at speed as well,ive had cars before and when the thermostat has gone you can see the temp drop while you drive/runs cool.What do you think about the chemical flush,when i rev the engine when parked and temp set to high and hold hand close to vent it is on the uncomefortable side of hot as soon as it drops to idle it goes cool,which is why i am thinking about the volume of water flowing through the heater matrix,any thoughts?

About the airlock i would think that the heater wouldnt work at all,no flow?

About the water pump if that was on the way out wouldnt it cause, overheating car will cruise at high speeds all day,no problem?