Rx400H Cabin Heat; How Does It Work?

[cduluk]

Hi all:

Do any of you know how the heating system works in the 06-08 Rx400h? Is the source of the cabin heat ONLY from excess heat off the engine, or is there a separate electrical heater to provide additional heat?

I only ask because of how quickly the heat comes on in the Rx400h, at least when compared to most gas-only vehicles.

When i had my RX300 before my 400h, on cold days (by cold, i mean outside temps below 40 degrees F), i used to drive the first few miles in the "2" gear so the engine would run harder to heat up the cabin quicker...

For the past couple days i had to drive my parents' ES350 and '09 RX350 (mine was at the mechanic), and it's crazy how long it takes for the air to blow HOT in both.

Thanks for any input!

[maseace]

I don't have any hard info, but it's supposed to be both heat from the engine coolant and heat from electric heating elements. The electric heating is not enough to provide all the heat so they kept the traditional heater core.

[maseace]

I found this info in the service manual:

- A compact, lightweight, and highly efficient electrical water pump is used in order to ensure the proper heater performance while the engine is stopped.

- A compact, lightweight, and highly efficient straight flow (full-path flow) aluminum heater core is used.

I could not find anything about electric heat, so I think it is all traditional heating except for the electric water pump that keeps the heat flowing through the heater core when the engine stops. This will not help until the coolant is warmed up, so there's still no immediate heat when first powering up.

[cduluk]

That makes sense.

So does the 400h have BOTH an electric water pump AND an engine coolant pump run by the timing belt?

[maseace]

It has two electric water pumps (heater water pump and inverter coolant pump), AND the standard engine water pump run by the timing belt.