How badly can the 12v batter lower mpg?

Service schedule for Gen2 USA models is listed as 10year/100K miles for first drain fill for both engine & inverter. 5year/50K miles thereafter for both loops.

All the bleeding issue on Gen2s come from the engine loop side. That is the more difficult one to perform. An Air Lift tool eliminates the difficulty b/c vacuum used to refill the coolant for each loop. Toyota lists steps for an Air Lift tool and w/o the tool, for both loops. I would imagine most shops use the Air Lift tool b/c time is money.

As you can see below, to add the drain/fill for the inverter, on top of the engine loops is truly easy.

The inverter is easy even.
1) Drain coolant at transaxle. Tighten bolt when coolant is drained.
2) Air Lift tool to refill eliminates steps 3&4.
3) Refill inverter coolant reservoir.
4) Crack the open the inverter bleeder, IG-ON for 20sec, OFF. Repeat until no bubbles and/or inverter pump is quiet; possibly 2-3 cycles.
5) Replace cap back on inverter coolant reservoir.

Engine loop is involved. Steps summarized and simplified.

1) Three drain locations: radiator, CHRS tank, engine block. Open one at a time. When coolant stops close.
2) Air Lift tool eliminates everything below (3-17).
3) Refill radiator.​

CHRS loop-sub loop off engine loop.

5) Open radiator bleeder.
6) Activate CHRS pump for 30 seconds at a time.
7) Squeeze hoses to help purge air.
8) Add coolant if needed
9) Repeat 6-8 until coolant level seems normal and air bubbles stop.​

Engine loop

10) Close radiator bleeder plug.
11) Cap on radiator after filling to full. Fill overflow bottle too.
12) Force Inspection Mode.
13) Squeeze hoses as engine warms up.
14) Heater on high.
15) Shut down engine, after a few minutes after operating temperature reached (thermostat open).
16) Check radiator coolant level after engine/coolant has cooled; a few hours.
17) Repeat 11-16 until coolant level in radiator remains stable and no sloshing sound heard while driving with heater.​

 

I will do this next weekend. Just need to get a digital multimeter. Any recommendations? There are so many out there...... I do have a battery meter thingy that I plug into the cigarette lighter thingy from my old car (a 1996 Mazda, RIP) Will that work?

 

If your meter gives a voltage readout, it may work okay, but I would check it against another meter before using it to make a $200+ decision.

You can get a decent-enough-for-occasional-use DMM at Harbor Freight Tools for about $5, and sometimes they give them away on their coupon deals.

The closer to the battery you can read, the more accurate you'll be, but for our purposes reading under the hood or in the cabin is okay, especially when the car is off.

 

No, 'cause voltage to the cig lighter outlet is cut off when car is off. Yeah, spring for a digital multimeter, there's lots you can use them for. $20~50 range are good, +$100 if your ego needs a boost, like me.

My latest is a "cheaper good one":

Milwaukee Multimeter 2216-20