Losing Coolant from Inverter and Engine Reservoirs

Hey Nick, welcome to the forum!

The only place the two systems meet is that the radiator, and I'm pretty confident the cores are separate even though they share the same radiator. Do you have any external drips?

 

Welcome to Prius Chat .

The systems are separate.

Is there any visible signs of leakage or puddle underneath the car?

Where are you adding the engine coolant: the overflow reservoir or the radiator?

Any recent damage to your Prius?

Good luck and keep us posted .

 

Have you checked the engine water pump for any crusty buildup?

 

Sounds like you found the likely culprit! Just out of curiosity, what's the year and mileage of the offending Prius? Also, has the coolant ever been changed?

Love your username, by the way.

 

Go borrow a cooling system pressure tester from your local parts store. Pressurize the systems and your leak(S) will show themselves. I would suggest you have at least two leaks but the cooling system pressure tester will confirm or deny this. Don't overheat your ICE that ally head and cast iron block do not tolerate high temperatures very well.

 

This sounds most plausible. It's an odd coincidence that both circuits are losing coolant, and the one place they're at least very close together is at the front, their two radiators. Either an accident, or rocks kicked up by a car in front of you, something managed to damage both radiators?

 

Second gen inverter rad is at the bottom?

 

I’m not sure the inverter circuit is pressurized??? If it is I don’t think a pressure testing kit would have that type of cap.

 

Skibob you may be right on the inverter side. But it certainly would work on the ICE side maybe he gets lucky and finds a common leak to both systems do not know.

 

I don't think a :common" leak will be found; both systems are autonomous.

 

Don't bother adding water to the ENGINE coolant reservoir you have to add water directly to the rad. The rad is probably empty.

Take the black plastic cover off the top of the rad. There's like 5 screws. You have to get your finger behind the screw and push it out as you unscrew the screw. Take cover off with car cool open the rad cap fill to the top. Put the cover back on but don't bother with the screws the hood captures it when its closed. Screws been missing on my 07 for 8 years. I like to be able to check the read level. Cover loose its fast and easy.

Inverter coolant leak is pretty rare. Engine coolant leak fairly common as the water pump wears out.

No where do those loops meet each other. Completely separate. They each have there own compartment in the rad. Top one is the engine with the rad cap. The small bottom one is the inverter that's serviced by the Inverter reservoir that's sits on the left side of the inverter.