Newbie - Inverter Coolant Pump Leak

welcome! did your car get the inverter pump recall?

 

The inverter pump runs in accessory mode--ignition on, engine off. (It does not run after the car is turned off.) It should be silent and you should be able to see turbulence in the inverter reservoir. If all this looks good, I'd drive the car with the fluid topped off. If not, there's air in the system and you should not drive it until it's bled out. There are YouTube videos on that. Pump replacement looks fairly simple as long as you can bleed the system correctly. In addition to a few small hand tools you'll need a section of clear tubing.

The pump you hear after you turn the car off may be at the engine coolant storage tank. You hear that one, too, when the car goes into "Ready" mode, before the engine turns on.

What were the codes? Anything to do with coolant? An inverter coolant problem would not cause a check engine light. Replacing engine coolant is a bit more complicated and more difficult than the inverter. Again, there are videos. And you should check engine coolant (when cold!) at the actual radiator cap, under the engine splash shield, not the reservoir. There are videos for that, too.

Good luck.

 

If you do end up doing the inverter pump, I would strongly recommend removing the driver side headlight to get better access. I posted a few pictures of it in my thread about replacing it. Red Triangle Light On, Thinking its the Inverter Coolant Pump | PriusChat

 

The inverter coolant pump does not run when the car is IG-OFF. The engine coolant heat recovery pump (located in front of the left front tire, can be seen when the front portion of the wheel well liner is removed) runs for a few seconds upon startup and shutdown. That is the pump making the noise.

1. Yes, you could replace both parts if you like.
2. No harm if you keep the coolant level up. Don't allow air to get into the coolant loop - evidenced by lack of fluid turbulence in the inverter coolant reservoir. If air is in the loop, you will need to purge the air out before restoring the car to service.

 

if there's any swirling, it's working. it's a go/no go situation.

 

Any idea what caused your engine coolant to get low and trigger the P0116 code? The leak we're talking about at the inverter pump wouldn't do that--separate loop. The Prius should not normally consume coolant. Leaks are pretty easy to spot (pink residue) and smell if it's vapor.

 

If the inverter pump was not working, the inverter would overheat and the AC compressor would stop working. However it is more likely that your AC system needs to be evacuated and recharged with refrigerant. A slight amount of moisture in the system can freeze up and stop the refrigeration process.

 

It sounds like you're loosing engine coolant, somewhere, and not from your inverter pump leak. The gurgling noise may be air in the engine coolant trying to circulate when the storage tank pump cycles on in "Ready" mode. Did you check your radiator again? (By the way, I just discovered yesterday that can be done by popping only two of the six fasteners in the splash shield, the ones farthest to the right of the car--gives you inspection, not working, access.) I would not drive the car until you solve the coolant problem--it may be substantial. Do you get cabin heat?

Edit: I just checked the code you got before, P0116, and it is not coolant level as assumed, it's "Range/Performance Problem" with the coolant and might be a temperature sensor problem--I'm surprised your mechanic didn't recommend that. It may be an easy fix. Still, it'll be wise to make sure there's no air in the system and that can be checked at the radiator cap when cold. Also, try squeezing the upper radiator hose on the driver's side of the radiator--when the system is correctly filled, it should be relatively firm, not "squishy." You'll have to completely remove the splash shield for that.

 

The coolant level should be all the way to the brim of the radiator cap and the reservoir should have coolant at least to the MIN level. Liquid coolant is not compressible, and if the system is full you should not be able to squeeze any hose like a sponge. The hose will definitely deform but should retain the same volume, if that makes sense. There should be no gurgling noise.

You might want to look into replacing the coolant temp sensor, which is probably giving you the code. That will mean draining the system, and you'll have to bleed it then anyway. That requires a Toyota-equivalent scan tool (or some skill with a jumper wire--do a search on this forum--I think Patrick W first published it). (A suitable tool, the Mini VCI, can be purchased for about $25 and needs an old Win XP or 7 32-bit laptop.)

I suppose there's a chance the coolant sensor could give a bad reading if the sender is not completely immersed in coolant. The sensor is probably at the top of the engine where an air bubble would like to live. That's just a SWAG (wild guess) and if correct, might solve the problem.

 

This is beyond my direct experience, thus the SWAG. With the coolant consistently full to the brim of the radiator neck (sounds like you checked it multiple times), and the heat working so well, the system should be completely bled. The car should be good to drive.

My pump makes a whining noise, but not gurgling. The hoses are firm, especially when the system is hot.

Have you tried opening the radiator bleed valve? It's on the driver's side, operated with a 6 mm allen key through a hole in the upper radiator support. You need some clear tubing (about 1/4 or 5/16" I.D.) attached to the outlet facing the engine. Open the valve (cold engine!) a half turn or so and you should get coolant rising an inch or so to the level of the filler neck. If this doesn't happen and the level at the filler neck drops considerably, you have air in there. (When bleeding the system, you're instructed to run the tubing into the open reservoir.)

The scan tool runs an electric coolant pump to aid in evacuating air from the system. Running that pump is necessary for any bleeding operation. Again, there is a hack for that. I bought the Mini VCI for other diagnostics and testing, so I haven't tried the hack.

Good luck--I know what it's like to be out in the sticks (Colorado mountains), though from where I live right now I can practically see a Toyota dealer out my front window. Makes it real easy for parts and coolant.