RX400h Heater Blowing Cold

[Ridgeback]

Winter is a good months away, but I thought I'd try and find an answer before the cold weather is upon us.

Towards the end of the cold weather this year, driving from cold, you could feel the heat from the vents getting warmer and warmer.

Then after about 5 mins, it would turn cold.

Despite turning the heater temp up to max, it just stayed cold.

It was only when I got on the dual carriageway and increased the speed to 60mph, it started working again.

After a couple of miles of getting toasty again, I turned off into a 30mph road, and it went back to cold again.

Any clues appreciated

[unclepoo]

Check the coolant levels straight away.....If it`s low on coolant, it won`t flow through the radiator and hearer matrix until the engine and water pump is spinning fast enough. A friend on mine was driving his shogun DID and the heater only blew hot on roundabouts turning right. I popped open the bonnet to check the coolant and there was nothing in the header tank and nothing visible in the radiator......it took about 3L of coolant to fill it to the required levels. The heater worked a treat after that and I would think the engine was happier too.

If it needs coolant, get 5L from toyota or lexus....DON`T BUY CHEEP.

[Ardent]

Lift the plastic cover and inspect the rad. Mine failed around rad cap area.

[Ridgeback]

Thanks for the advice guys, but the coolant level is spot on.

Rgds

[unclepoo]

Don`t forget, there will be 2 cooling systems, One is for the ice engine, one is for the inverter/electrical system.