[Daddique]

Happy New Year, all. I'm a totally newb to this car and hybrids in general. I recently bought a 2007. I believe it has a leak in the hybrid cooling system as I'm constantly needing to add the Asian red antifreeze to the reservoir in order to keep the warning lights off. I do not see any evidence of the fluid leaking on the ground or in the engine bay, but everything is pretty tight in there to begin with.
I've searched these forums and the broader internet for anyone with a similar issue but don't seem to find any troubleshooting ideas for this particular problem.
What are the most common causes for fluid loss in the hybrid cooling system? The pump? Hoses? And how best can I gain access to those components? There is a big "do not touch" warning on the high voltage system adjacent to the reservoir.
I'd prefer to DIY so that I can learn more about this car and be more capable in the future.

I appreciate any help.

 

[cj1]

For DIY best subscriber to all data or similar for specs.
Let us know what you find.
Sorry don`t have a better answer.

 

[ukrkoz]

Water pumps. They even had recall on them. Look for red beard along the belt run and on the hood inside.

Also, reservoir you talking about is not coolant reservoir. Well, yes, but. It's for the inverter, not for the engine. You have 2 cooling systems - main one for the engine and 2ry for inverter.

So which one is getting low - main one on the passenger side or the 2ry one right next to the hybrid synergy drive? Those are independent circuits.

 

[Daddique]

Water pumps. They even had recall on them. Look for red beard along the belt run and on the hood inside.

Also, reservoir you talking about is not coolant reservoir. Well, yes, but. It's for the inverter, not for the engine. You have 2 cooling systems - main one for the engine and 2ry for inverter.

So which one is getting low - main one on the passenger side or the 2ry one right next to the hybrid synergy drive? Those are independent circuits.

I'm talking about the hybrid cooling system/drivers side reservoir next to the synergy drive. The cooling system for the inverter. As I understand it, the inverter pump is accessible from under the vehicle. So I know where the reservoir is and I'm pretty sure I know where the pump is. I imagine there are rubber hoses connecting the two. Aside from those three components, are there any other places where it's likely I could be losing fluid?

 

[ukrkoz]

Thank you for clarification.
We did not have a whole lot of issues with inverter cooling system. Hence, not a whole lot of posts on those, unlike water pumps. As in - engine water pump.
I'd suggest to introduce UV dye into the inverter coolant, give it few days, and then scope with UV light, where exactly leak is. Kits for that are sold for around $30 in parts stores. Should there be no external leaks, keep in mind, inverter coolant also cools down motor generators and THAT will mean internal leak into PSD. Possibly, why you do not see any drippings underneath the parked vehicle.

 

[TryAgain44]

The car is certainly old enough to have corrosion in the inverter cooling circuit - including the 'small radiator', associated hoses, and the electric pump. The 'worst case scenario' is would be contaminated lube (think pink mayo) in the PSD. Nearly as bad would be internal leak in the inverter heat exchanger.

The more probable ones are leaky hoses or hose connections, due to corrosion. Ditto with the heat exchanger, particularly in the salt belt. With the car being 15 years old, rubber hoses going 'bad' is a likely problem. Give the accessible ones a squeeze to see if they're cracked or crunchy.

 

[timjemad]

I have a 2009 model with the same problem, inverter coolant loss. I have to top it off very often and no sign of it leaking. The car drives ok but has to keep checking the level and add sometimes every 200 miles.