Inverter Coolant Pump failed today

[MercerGirl]

Sounds like this is getting to be a common problem. AC stops. A few miles down the road display lights up with warning lights and engine cuts off.

After talking to dealer, I was lucky to make it across town and get a replacement with an upgraded unit and back on the road in two hours.

2007 Gen II
40k miles

[richard schumacher]

Yep. Hobbit tore one apart and displayed the design inadequacy (a single point rotor bearing). IMHO they'll all fail eventually.

[SageBrush]

Though the greater majority of the failures have been in AZ and Fl so far. I suspect that heavy AC cooling use is a major determinant.

[Patrick Wong]

Originally Posted by MercerGirl

...After talking to dealer, I was lucky to make it across town and get a replacement with an upgraded unit and back on the road in two hours.

I'm a bit surprised that a two-year old car with only 40K miles has a failed inverter pump. I question the assertion that the replaced unit is "upgraded". I recently installed a pump on my 2004 as a preventive move, and the new pump visually looks identical to the old.

Originally Posted by SageBrush

Though the greater majority of the failures have been in AZ and Fl so far. I suspect that heavy AC cooling use is a major determinant.

Well, the inverter pump duty cycle does not change as AC is used or not used, since the pump runs at all times that the car is IG-ON or READY. I would say that a failed pump becomes quickly apparent when the car is driven in hot ambient temps, while in more moderate temps a car that has a failed pump but is lightly driven may continue in operation without warning lights for an extended length of time.

[SageBrush]

Patrick, the pump works at the same power output regardless of inverter temp ?

[Patrick Wong]

Originally Posted by SageBrush

Patrick, the pump works at the same power output regardless of inverter temp ?

Yes.

[SageBrush]

Does the pressure in the system increase with temperature ?

[tochatihu]

The electricals coolant loop is not pressure sealed as the engine's. The normal operating temperature is quite a bit lower as well (low 70s vs high 90s oC), so I don't think the pressure rise is much of a factor.

[MercerGirl]

Well, the inverter pump duty cycle does not change as AC is used or not used, since the pump runs at all times that the car is IG-ON or READY. I would say that a failed pump becomes quickly apparent when the car is driven in hot ambient temps, while in more moderate temps a car that has a failed pump but is lightly driven may continue in operation without warning lights for an extended length of time.[/QUOTE]

Maybe I should have said redesigned pump. Dealer said it was a new Improved part.

Question. Did I risk damaging the car by driving to dealer with warning lights?

Is it ok to assume that if something malfunctions and car runs it wIll do no additional damage to drive briefly?

[richard schumacher]

Technical whiz Hobbit examined a new pump. It didn't look any different than the original design so they will probably fail the same way.

If this pump fails, driving slowly a short distance may be OK; several people have done it with no additional harm, and if your car is fine after replacing the pump then you did it also. But there are several things that can go wrong that will cause a lot more damage if you try to continue driving, so in general do not assume that it's safe to do so.