1.5 L Toyota block heater

[bwilson4web]

Hi,

The Prius, Echo, and Scion vehicles all share the same 1.5 L engine block so their respective warm-up times on a block heater should sort of follow this rough measure. After a little over an hour of block heater time:

• 5 C - traction battery temperature (ambient)
• 13 C - MG2 temp, the one furtherest away from engine in transaxle
• 18 C - MG1 temp, the one closest to engine
• 36 C - engine block temperature, ~31 C increase

After four hours, I've seen ~35 C difference between ambient and block temperature. Thereafter, the block temperature begins changing in proportion to the ambient (aka., it doesn't seem to get any warmer relative to ambient.)

My math suggests that based upon Huntsville AL rates, a one hour, block warm-up is about as long as one wants to run it based upon local electrical and gasoline rates. Any longer and the additional electrical costs begin to exceed our local gas savings from a shorter warm-up.

I have not tried to solve the equations but even 30 minutes is enough to see a savings. The best approach being a circuit you can "turn on" in the house when you are fixin' to get ready to leave.

FYI, this shows the typical warm-up curve for my NHW11, 1.5 L Prius engine:

The goal is to get to 70 C quickly so the car can flip into Stage-4 and saves about 2 of the ~5 minutes it takes to warm-up. The block heater nicely brings the temperature up to 40 C and then if you have a thermistor hack, it can all but instantly spoof the car into Stage-4. This is when the engine will cycle off as soon as it is able. <grins>

NOTE: The USA EPA is worried that people making modifications to their cars may change the emissions characteristics. In fact California saw legislation or a vehicle inspection rule that was going to require a full emissions certification for every after-market, do-dad sold for cars. But if located behind the glove box, a thermistor hack should be all but invisible except to the excessively curious. <GRINS>

Bob Wilson

[MadisonMPG]

I'm assuming my rates are near yours, so 1 hour it is.

[NeilBlanchard]

Hi Bob,

Is this block heater something we can get from Toyota?

[bwilson4web]

Originally Posted by NeilBlanchard

Is this block heater something we can get from Toyota?

Toyota Canada sells it and a few folks in the USA offer it:

PriusChat Shop : Toyota Prius Engine Block Heater [Prius EBH] - $59.00
Toyota Prius Hybrid Engine Block Heater
Engine Block Heater (2004-2010 Toyota Prius) , PU140-00900

My local Toyota service center when I asked many years ago said they didn't have that part in their catalog. So I bought it from a Canadian parts store and then came the fun part ... installing it. It is in a awkward place.

Since you are in the Massachusetts area, see if you can get with good Prius friend Hobbit. He is skilled in this area.

Bob Wilson

[NeilBlanchard]

Hi,

I checked with my local Toyota dealer, and they have the electric block heater for $40!

Does anybody know if this unit also fits the 1.8L in the xD?

[orange4boy]

Just picked up a block heater for my 2003 Prius.

Documentation shows:

Toyota:
2000-2008 L4 1.5L (1NZFE)
1998-2008 L4 1.8L (1ZZFE) TRANSVERSE
2000-2007 L4 1.8L TRANSVERSE
2002-2008 L4 2.4L

Also fits a bunch of other Toyota products.

They don't list the 1NZFXE (Prius ICE) but I believe the casting is the same as the 1NZFE.

Mine was $37.19 Can. before tax at Lordco but I have an account. List is $63.99.

Oddly, mine didn't come with the grease that i have seen in other kits. Anyone know what kind it is or what could be substituted?

[Daox]

I'd try to find some thermally conductive paste.

[bwilson4web]

You might call the provider and ask if another package has the little tube. Mine looked like petroleum jelly. I agree that thermal paste would be a good choice.

Bob Wilson

[NeilBlanchard]

Hi,

I was peering in and around the block/clutch area on my xA, trying to see the spot where this sucker goes. Does anybody have a picture/drawing of the location?

[bwilson4web]

In the Prius, you can either approach it from the top or the bottom but it isn't easy. When facing the engine, it is on the right side, about 5-6" down and about 3" from the exhaust manifold. I have to remove the windshield wiper assembly to get enough space to reach the hole.

If under the car, you can reach up and find it without having to remove the windshield wiper assembly. But of course you need to give the engine time to cool off so the manifold won't burn your hand. But reaching up, the blood drains from your arm and hand so it became a series of stages. It wasn't fun but once done, voila.

Regardless of the approach, be sure the heater element 'clicks' into the hole. Relative motion can lead to connector failure.

Bob Wilson