Fan blade orientation?

[andyprius]

In a earlier post, you said " If I could get the fans to run", Have you checked all the fuses and relays associated with the problem? By working on the car before the dealer has had a chance, you may void the warranty. Did you read Ginnys " I blew up my Inverter" Thread? I have not torn apart my ICE cooling system however it is highly possible that the fans are correct, and they spin in opposite direction.

[snijd]

The fans do run--they were running when I shut it down a couple of days ago. However, they are blowing air in the opposite direction desired. The dealer said he'll be happy to do the work--but because I purchased the vehicle used, the warranty is still being transferred, and I may have a couple of weeks to wait. However, point taken regarding risks to the inverter and cooling system. I may indeed just pay the dealer to do the work, since I know exactly what repair is needed. Thanks for the inputs!

[KayakerNC]

Originally Posted by snijd

The fans do run--they were running when I shut it down a couple of days ago. However, they are blowing air in the opposite direction desired. The dealer said he'll be happy to do the work--but because I purchased the vehicle used, the warranty is still being transferred, and I may have a couple of weeks to wait. However, point taken regarding risks to the inverter and cooling system. I may indeed just pay the dealer to do the work, since I know exactly what repair is needed. Thanks for the inputs!

Warranty? Was this a certified vehicle?

[andyprius]

Originally Posted by snijd

The fans do run--they were running when I shut it down a couple of days ago. However, they are blowing air in the opposite direction desired. The dealer said he'll be happy to do the work--but because I purchased the vehicle used, the warranty is still being transferred, and I may have a couple of weeks to wait. However, point taken regarding risks to the inverter and cooling system. I may indeed just pay the dealer to do the work, since I know exactly what repair is needed. Thanks for the inputs!

OK, Now I have the whole story, there are several recent inputs on the cooling system. It seems if you don,t drain the whole system but only the radiator you will not have to purge the trapped air. I would try not to open up the inverter cooling system at all. There are also threads on this that you should read before proceeding. Somebody put those fans on backwards so you should be able to get at them without too much difficulty. It sounds like there is no room to get at the fans, so you have to remove the engine (ha,ha) just kidding or loosen the radiator. Maybe one of our knowledgable techies will join in and advise. Good Luck. Andy. keep us posted.

[snijd]

Both fan blades are now in their correct locations. I double-checked the part numbers, descriptions, and locations with a dealer. The 7-blade fan belongs on the right, and the 5-blade fan goes on the left, as you sit in the driver's seat. So, yes, they can be inadvertently reversed--either blade fits nicely on either motor, but they run in opposite directions. BTW, they were facing the correct direction, just turning the wrong way. I didn't have to remove any hoses or drain anything--it's just a tight squeeze reaching up to place the nuts. This wasn't such a difficult job after all. Thanks for all the inputs!

[Patrick Wong]

Originally Posted by snijd

Both fan blades are now in their correct locations. I double-checked the part numbers, descriptions, and locations with a dealer. The 7-blade fan belongs on the right, and the 5-blade fan goes on the left, as you sit in the driver's seat. So, yes, they can be inadvertently reversed--either blade fits nicely on either motor, but they run in opposite directions. BTW, they were facing the correct direction, just turning the wrong way. I didn't have to remove any hoses or drain anything--it's just a tight squeeze reaching up to place the nuts. This wasn't such a difficult job after all. Thanks for all the inputs!

Hi Rob,

I haven't paid attention to the two radiator fans before, so please bear with me regarding the following Qs:

• Do the two fan motors have the same part number?
• I take it that you personally swapped the fan blades? What does this procedure require? How hard is it to remove the blade from the motor?
• Did you need to swap the two fan motors; or did you leave the fan motors at their original locations?
• When looking at the fans from the rear of the car facing forward, which direction is each fan supposed to turn (clockwise or counterclockwise?)

I am also surprised that this problem did not manifest itself to the original owner. This seems to indicate that the car suffered front-end accident damage and the fans were incorrectly installed?

[tochatihu]

I can imagine that a Prius could be driven for quite a while without firing up the fans. If you don't use A/C and happen to avoid large hill climbs, it will just self-cool. Not as many kilowatts of waste heat go that way as in most other vehicles.

However, as soon as the blades are spun (backwards) the radiator will stop acting as a heat exchanger and you should very quickly get the coolant into "hi temp warning light" territory.

This counter-rotating fan interchangeability is an interesting design oops. I suppose that Toyota will modify, if they've any money left over after "operation lithium"

[snijd]

Patrick,
See my response below...

Rob,

• Do the two fan motors have the same part number?

No--and the prices are different. One turns clockwise, the other turns counter-clockwise.

• I take it that you personally swapped the fan blades? What does this procedure require? How hard is it to remove the blade from the motor?

Yes, I personally did the work.

1. Removed the plastic fairings/covers beneath the radiator (I also removed the inner wheel wells, as it seemed easier than separating the other pieces), and the plastic pieces on top, in front of the radiator.
2. Removed bolts retaining radiator, on top and bottom.
3. Removed a couple of electrical plugs to make it easier to maneuver the fan housing so as to make room to reach up between the radiator and the fan housing with a ratchet to reach the nuts on the fan blades.
4. Loosened fan blades with 8mm socket on 3/8" drive--a long drive handle made it easier.
5. The fan blades came right off.
6. Reverse procedure to reinstall fan blades. The keyway is identical on both motors, making it easy to inadvertently reverse their position.

• Did you need to swap the two fan motors; or did you leave the fan motors at their original locations?

I left the fan motors where they were. To have moved them would simply move the problem to different locations.

• When looking at the fans from the rear of the car facing forward, which direction is each fan supposed to turn (clockwise or counterclockwise?)

Left: clockwise; Right: counterclockwise.

I am also surprised that this problem did not manifest itself to the original owner. This seems to indicate that the car suffered front-end accident damage and the fans were incorrectly installed?

Yes, this is very likely the result of maintenance performed on the vehicle, rather than an assembly line error. I wonder if the previous owner sold it to me because he was stumped at the vehicle's strange behavior--he certainly made no mention of it when showing me the car. It was surprisingly tolerant of the backwards cooling arrangement. The primary manifestation was the intermittent air conditioning. I only saw a high temp warning once, and only for a few seconds. I have no idea why he didn't get it fixed, since it was under warranty. Maybe the dealer was stumped, too? Seems difficult to believe.

[andyprius]

Congradulations. A very nice write-up. We all got an education on that one. AND a belated welcome to Prius chat.

[andyprius]

Now I have to do some fan research. In studying my little electronic equip cooling fan, which I keep beside me, I notice that the airfoil is toward the front or facing me and turns counterclockwise. So in the case of the prius fans, even tho they are of different design and turn in opposite directions. The airfoil must be the first part to cut thru the air in order to apply proper air flow direction. Just an afterthought.