Inverter Coolant Pump failed today

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

 

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.

 

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.

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.

 

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

 

Yes.

 

Does the pressure in the system increase with temperature ?

 

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.

 

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.

 

It depends upon which warning lights are on. In general, if amber-colored warning lights are on, then you can drive without worrying about imminent permanent damage. However, you should also expect that the systems associated with those warning lights are operating in a degraded mode, and the car should be serviced as soon as possible.

In general, if red warning lights are on, then you should assume that further operation can lead to permanent damage to the systems that are associated with those lights - or that the systems are not functioning.

Regarding the question of a redesigned or improved coolant pump, I am aware that a redesign was put into effect. However I believe that 2007 model year vehicles had the redesigned pump installed, so the fact that your car had a failure with relatively low miles is indicative that the new design is not perfect.

The pump does not have a part number on it, so it's hard to decide whether a particular pump contains the original design or benefits from the improved design.

 

Just another data point for this thread. Mine failed this week during the heatwave in California (110 degrees).

Parts,labor,tax = tad under $500

I have a Gen II 2006 Prius with 76,000 miles.

 

Is this a difficult job for a DIY type person? Seems like a very expenssive fix for a low pressure pump replacement!

 

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

 

Thank you Patrick. H