Inverter Coolant Pump takes a dive

Where is the thread on draining and refilling the inverter coolant?

 

See my post here:
http://priuschat.com/forums/gen-ii-.../65173-how-replace-inverter-coolant-pump.html

as well as post #61 of this string. Both explain how to refill the inverter coolant after that system has been drained.

 

up/ I think this post and Patrick's in the other thread should be a sticky.

 

I've just put together an analysis of why the pumps likely fail as
they do somewhere around 100,000 miles. Eventually I'll do my
own and that'll include displacing the left headlight [which is
actually easy, I already have pix] to get a whole lot more
working room back there.
.
Of note, I've got a new pump ready to go, that Steve ordered
for me. He experienced a pretty long backorder too, but it
finally arrived.
.
_H*

 

Thanks hobbit! Great informative write-up, as always.

 

I called my dealer and they had one on the "special order shelf". Since it was setting there for over 30 days, they let me reserve it. Im picking it up tomorrow and driving up to visit Steve Woodruff on Monday. We will be replacing the inverter pump, water pump, spark plugs, PCV valve and serpentine belt. Any other recommendations while we are at it?

 

Are you not changing the coolant as well?

 

So the design of the Gen II pump has not been changed? Dang. That means that my replaced pump will also fail, someday. Can a Gen III pump be used in a Gen II?

 

I assume the engine and inverter coolants will be replaced since you are replacing the two pumps.

How about the transaxle fluid?

How old is the 12V auxiliary battery? If more than 4 years old you might consider replacing that before winter.

 

I have the new genII pump here; looks exactly like the one in
the car and the dead one I took apart except for the silver mounting
bracket instead of the black one. [And I'm probably going to
send that bracket to Steve because mine isn't mangled from a
collision and he says he needs extras]. Heck, it didn't even
need to come with a new bracket but it did.
.
+1 on the transaxle fluid if you haven't changed it recently..
Just did mine at 110K or so and while it wasn't as brown as the
first load, it clearly wasn't spankin' new anymore since 55K or
whenever I changed it. Less gunk on the magnet, though.
.
_H*

 

As usual, excellent writeup

So it does appear as though the single sleeve bearing support on the coolant pump depends on the coolant for lubrication. The only way to determine if the coolant is ok for that purpose is a detailed lab analysis - it would be cheaper to just replace the coolant

Commercial and industrial cooling systems require "supplemental charge additive" to maintain the cooling system protection, presumably that includes lubrication for the water pump.

As the coolant chemistries of commercial and Toyota SLLC are probably incompatible, I would not recommend trying to add any sort of commercial additive, or any additive period

 

I take it the new and improved pump cannot be used as a replacement in G2 Prius ?

 

Tiny page update, just to add that the pump draws 1.8 amps
when running. do not know about the lubricity of coolant but it *is*
sort of slippery feeling, and once a skin of it develops between
the spinning rotor and shaft it might actually work okay as a
running medium. But any rotor imbalance is likely to cause some
part-to-part contact somewhere. Briefly running the new pump
dry sounds pretty horrendous, in fact -- this is *not* anything
like a precision bearing!
.
_H*

 

Yes, the coolant in both systems will be replaced. I replaced the 12V battery last week with the elearn Optima. I replaced the transaxle fluid at 130k. But since it looked pertty good and there was no gunk on the magnet, I was going to wait until 250k or so. If Steve has the fluid, I guess I will change that also.

 

Just picked up mine at the dealership this morning. I lucked out because someone ordered it awhileback but never picked it up. It has the mounting bracket with the clear zinc chromate plating.

When you say that the pump draws 1.8A, at what voltage? I assume 12V? I when the ingition is on and I am in park, the SG shows 1.0A draw on the traction battery. If the pump wasn't running, would the parasitic load go down to 0.9A?

 

The inverter coolant pump runs at 13.8V which is the voltage on the 12V bus. Hence that pump uses around 25 watts of power given Hobbit's measurement.

For the sake of our discussion, assume the DC to DC converter is operating at 100% efficiency (it probably is actually 90% or more.) Since the traction battery is operating at around 220V or so under normal use (201.6V nominal), a reduction in load of 25 watts would mean a reduction of ~0.11A.

 

Never give me an opening line like that. I risk a lifetime ban. But seriously, for HD equipment, the supplemental charge additive is designed to protect against corrosion, liner erosion, and provide lubrication for the pump

Old fashioned coolant with silicates is forbidden in most industrial/commercial and HD equipment. That same stuff would probably raise hell with the inverter cooling passages

BTW did you ever figure out what that glop was inside the cooling passages of the inverter you autopsied? I'm wondering just how well those early inverter plates were cleaned after manufacturing

No, nothing like that. Just a sleeve bushing

 

Another one bites the dust. My '05 with 56,740 miles on it had the inverter coolant pump fail with the lotsa-lights symptoms on a toasty Florida Saturday, at 1:10 in the afternoon. I was about 8 miles from a Toyota dealer, so I called, described the symptoms, and they said to bring it in and they'd have a tech check it out, but the service department closed at 3. The Owner's Manual implied that driving it to the dealer wasn't a smart move, but we did. Long story short, we were on our way in under 2 hours with a new p/n G9020-47031 pump and some 00272-SLLC2 coolant, all covered under warranty (just in the nick of time). All in all, I'm a happy camper, but a little upset that I hadn't read this excellent thread a few weeks ago.

Does anyone know what improvements, if any, were made in the 47031 pump over the previous p/n 47030?

 

One more

My wife's inverter pump died while we were out last night. Triangle warning light, check engine light, VSC light, one with an exclamation point, and a small car icon with an exclamation point over it at the top of the display screen. AC stopped working, too. Fortunately, we weren't far from home, and the dealer got us in first thing in the morning with a loaner and had it fixed by lunch. It's an '06 with about 40k miles on it, and it was all covered under the warranty.

It seems like this pump should be a bit more robust-- without it, a whole lot of more expensive bits get toasted. Does anybody make an aftermarket unit that's more durable?

 

Re: One more

TSB EG001-07 says "The HV coolant pump assembly has been improved to address this condition", but I haven't yet found out what the specific improvement us. The pump on the 2010 is supposedly very much improved (mentioned earlier in this thread, I think). You might think the new G9020-47031 pump and the 2010 model year pump incorporate the same improvement(s), but who knows?

In any event, I doubt any aftermarket pump would be commercially viable, and would certainly void the Toyota warranty.