HV pack cooling fan, what is "normal"?

I cleaned the HV pack blower fan today. The vanes were dirty, but only to the extent that they were covered with dust and dirt, not that that contamination blocked any of the air pathways. The rest of the inside was clean. Also no dog hair, which was reassuring, since some has been transferring into the car from the house on our clothes, even though that dog has never been in the car. The thing is, when tested with Techstream (active tests, 1,2,3,4) this blower was pretty darn anemic. On 4 it was blowing hard enough to make the little outlet flaps on the side of the trunk area open, but it was at best a "gentle breeze". Pulled off the tube to the pack and felt the output right at the blower, and it was moving some air, but definitely not a lot. The air felt like it was moving maybe 15-20 mph, tops. No DTCs or anything, and it is very quiet. When the cage was spun with a finger it would make one or one and a half turns before stopping. For most fans that indicates a lack of lubrication and probably higher current draw and/or lower RPM. The pin to pin resistance on the blower was 7 Ohms (measured with my neighbor's Fluke, my Harbor Freight cheapo multimeters cannot measure small resistances like that accurately) which is within the "less than 9 Ohms" specification.

Cleaned it with some cotton swabs, pipe cleaners, and a toothbrush. Cleaned as best as I could under the cage with a pipe cleaner, by poking it in the outlet and spinning the cage. When it was done it didn't spin any better than it did before.

But I have never seen a brand spanking new Prius HV pack blower, just this one. My only point of reference is the IMA fan on a Civic Hybrid, and those could be used as leaf blowers. How freely should this Prius blower spin? Should the output at the blower (no tube to pack) be forceful, or gentle as was observed? The blower is apparently a ~ $250 part, so I don't want to replace it just on a hunch it might be bad. Also, if it is bad it is just the motor, nothing wrong with the cage or housing. $250 is for the whole thing. But the cage is mounted in a very odd way to the shaft of the motor. There is some sort of big cylinder doohicky (maybe a round nut or part of the cage?) on the shaft, and coming through it is the very tip of a threaded bolt, with some orange coating on it. Perhaps some form of loctite. If the motor is bad, has anybody ever replaced just that part?

 

My personal experience with lubricating small high speed motors (from computers) is that oil is a very temporary fix. This was true even on the small blowers analogous to the HV blower. A fan may last 8 years, slow down or stall, be oiled so that it works "normally", and then bog down again in 2 weeks or 3 months. Never as much as a year. Big motors, like on a house furnace have cloth/sponge like areas to hold oil. Put some more on there and those can be good for many more years. But little motors don't usually have those built in oil reservoirs. The safer bet would be to replace the motor (not the whole device, nothing wrong with the plastic), but I could not find pictures of anybody taking one of these apart. I fear that the cage may be molded directly onto the motor shaft.

 

Lucky trip to the junkyard. We went to get an antenna base for our Prius, and lo and behold the very first car in from the gate was a 2005 Prius with an intact antenna base (antenna too, but the rubber was mostly gone) and a pack blower still in the car. The latter was just begging to be removed, as it was totally exposed by previous scavengers. So for twenty something bucks I picked it up.

Part numbers 87130-47070, 117200-2913. Under the label it has on the motor 272700-0230 12V 2 09. There is a 2 pin connector with + and - stamped into the plastic on either side. Motor by Denso.

This is only the 2nd one I have held in my hands, the first being the one still in my car. This new one is reasonably clean, a little dust on the blades. Nothing to mess up the air flow. The one in my car spun better than this one, going 1 or 1.5 turns when pushed with a finger. This one only spins about .5 turn before stopping.

If constant 12V is applied to the pins should it turn? Or does it need a PWM signal at some frequency? I want to experiment with lubricating it, so it would be good not to needlessly burn it out.

Also, I asked in the yard (a "pick your part") why there were never any packs in the cars. The guy at the register says that its because they pull them and ship them in big lots to some company (which he didn't want to name) which rebuilds them. Not like wheels and tires, which they pull off before putting the cars up on blocks, but which they do sell from big stacks near the entrance.

 

Have any of you found a method to remove the fan cage from the battery cooling fan? Most fans like this hold the cage on with a small metal retaining clip which grips the shaft just above the cage plastic. These are installed by tapping them down into place from the top. Either that or they just press the plastic cage onto a shaft with one flat side.

This Denso fan has a very peculiar construction. If you look at any of the pictures on this forum you will notice that the plastic around where the shaft protrudes into the cage is a different color from the cage. That is because they are two separate pieces of plastic. The top piece is a cylinder with 4 square tabs protruding from the bottom (like the top of a castle turret, but upside down). The fan cage has tabs in the opposite positions. The two sets of tabs mesh up like the the teeth on a pair of gears. Hard to see from the top, but if you poke a small mirror in next to it is pretty obvious.

I suspect that if 4 (very) small wedges were forced into the gaps above the cage tabs it might push the retaining "castle turret" up and off the shaft.

It is also odd that the tip of the shaft that protrudes into the cage is rusted on both of the ones that I have looked at, while the other end of the shaft, under the label, is shiny looking. Admittedly the former sees a lot more air than the latter. It does make me wonder if the protruding metal might not actually be part of the motor shaft.

Why take the cage off? Because electrical motors often have a bit of felt soaked in lubricant that keeps it running smoothly for a long time. To service a motor like that the felt must be replaced, because as the motor ages, it can turn to dust, and then it won't hold oil even if some is dribbled in (somehow, like from the other end). I'm not sure if this motor comes apart, but if it does, the screws to do so are probably under the fan cage, and so invisible in the fully assembled unit.