Coolant thermos retrofit - humour me

If you can obtain the North American engine ECU as well as the other obvious parts then you might be able to retrofit this. You can consult techinfo.toyota.com to obtain North American service and repair info (if that site will accept your UK credit card.)

However I really doubt the benefit would be worth the trouble and effort involved, and you might have service issues if the engine ECU installed in your car is not UK original. I owned a 2001 as well as 2004 and did not feel that the first 5 minute fuel economy bar on the 2004 is noticeably different from the 2001.

Good luck with your project should you decide to pursue this.

 

I agree with Evan. I think this is mostly for emissions. You would be better off to install a block heater.

Tom

 

Note that the thermos -IS- lossy, and has -NO- effect in the winter here in Edmonton. Well, let me correct myself. The coolant is about 5C warmer when the pump runs according to the Scangauge. So I suppose that's an effect. I'm pretty sure that has no effect on the emissions, as it brings the coolant from -7C to -2C. The block heater brings the coolant from -7C to +30C.
What the thermos system -DOES- do is add more parts to fail. How about we swap parts?

 

It has an effect on emissions as tested using the standard EPA procedure. The practical effects are probably small or non-existent with your climate.

Tom

 

+1

You would probably get a lot more consistent results with the block heater also.

 

Also, the thermos won't be a simple installation. I don't know exactly how the whole system works, but I bet there's a few valves involved, and would impact a UK dealer to do service on your car if your Prius is running a different software version.

I agree with the above, the EBH would bring more benefit and less cost+complexity.

 

The NA 2004-2005 Prius has the following engine ECU part numbers:

89661–47070
89661–47071
89661–47100​

89661–47101

So, if you can find the engine ECU in your car and determine its part number, you can compare to the above list.

 

I'm pretty sure the UK ECU doesn't have the firmware for the thermos. If it did it would throw codes because it looks for a temp change when it starts the coolant transfer pump. If it sees no change it is supposed to set a code. There may be an escape clause in the programming for that, as if the car sits long enough the coolant in the thermos is the same temp as in the engine. But it may also look for other signals showing the pump system is working, because when it fails you do get codes. Not having it installed would be interpreted as a failure by the firmware (i.e. if you removed all the components you would get codes stored).

My Prius has the dual 400W heaters. The only time I notice them is in early fall or late spring. They have no effect in winter that I can see, which is understandable. That isn't enough power to provide noticeable heat when it's -20C (or even 0C). They may be in the UK Prius as well. Ask your dealer (good luck with that ).

Note that the cabin fan won't turn on until the coolant is above about 40C. Unless you have front defrost turned on.

 

*edit: found my answer*

 

Sorry, you replied after I saw that pdf link earlier in the thread ... you're pretty quick on the trigger

http://www.autoshop101.com/forms/Hybrid06.pdf

It shows the two 165W heating elements in the heater core, therefore all airflows (floor, dash, front windshield) "benefit" from it ("benefit" being a generous word... there isn't much that 330W can do in a real winter).

 

Can we install a engine heater that connects into the heater lines and warms the whole coolant system, instead of just the engine block? Why not this type instead of the EBH that every one is installing?