Yaris Diesel Heater Problem

[SW_Yaris_Owner]

The heater in my three year old Yaris diesel has just gone from toasty hot to lukewarm. The coolent level was a little low, but not enought for the level light to illuminate, otherwise everything looks OK. Any suggestions before I give the local dealer the deeds to my house by way of payment?

Thanks.

Additional Note. I've just been for a drive and the heater went from toasty to chilly, almost as it the A/C had switched in. The light on the A/C switch didn't come on, but could it be an electrical problem? Any tips for further diagnosis?

[Benno_uk]

The heater in my three year old Yaris diesel has just gone from toasty hot to lukewarm. The coolent level was a little low, but not enought for the level light to illuminate, otherwise everything looks OK. Any suggestions before I give the local dealer the deeds to my house by way of payment?

Thanks.

Additional Note. I've just been for a drive and the heater went from toasty to chilly, almost as it the A/C had switched in. The light on the A/C switch didn't come on, but could it be an electrical problem? Any tips for further diagnosis?

Low coolant level causes the heater to go cold. Top it up in the radiator with the engine ticking over. The heater will probably get back to normal. But why is the coolant low? Look under the car and hope and pray to find a coolant leak. If not, the head gasket blowing is not uncommon on these cars - and it gets worse. If the head gasket has blown it`s been known to be the head thats damaged that causes the gasket to blow which means a new head. !Removed! costly!

Oh the coolant level light? You meen the blue/red light in the dash? Thats the coolant temperature light not coolant level.