Avensis 2.0 D4D Diesel Interior Heater Blows Cold At Idle

[Paul Hutchinson]

Hi noticed recently that the heater works ok when driving or when revs high,but at idle the heater blows cold air and controls still at hot,when i rev the engine it blows warm? Thinking about chemical flush to clear heater matrix,it might be partially blocked.Tried warming up with rad cap off and squeezing the top/bottom hoses to release trapped air-no change.

Any one tried a chem flush before,got any advice about them.

[dervdave]

Worth a try in this section as well Paul

[Phil01]

Check your coolant level in the radiator