Down-draft radiator fan failure

[mrkane]

Gurus:

My Kohler/Yanmar generator shut down due to coolant over-temp. I found the squirrel-cage blower had stopped. The motor would rotate only a partial turn when spun by hand (with the engine off.) Later, after cooling, the motor now spins more freely. After cooling overnight, the fan spins very freely, with no problems with the bearings noted. The generator ran for several hours before the fan stopped again. The motor case was quite warm.

Is this a symptom that this motor should be replaced? Capacitor?

The motor is marked GE 5KCP39LG, 1075 rpm, 1/3 HP, 230 VAC. Web searching has not located an exact GE replacement, but rather many other 5KCP39xxx versions. I would prefer to have a replacement on hand before starting the swap, if possible. (It appears it will be necessary to drain the coolant to get the fan housing out.)

Any suggestions?



--M.R.Kane
1987 PT40 'Sleipnir'
currently in Iron River, MI

[davidbrady]

Hi M.R.,

You're start-run capacitor may be faulty but more likely your fan motor is shot. My guess is that your motor is lacking lubricant and as it heats up whatever lube is left becomes thinner until the motor seizes. While you're in there in makes sense to give it a new capacitor. (Of course this all assumes that the motor is getting the proper start voltage).

The capacitor is a GE 5uF 370VAC unit which should be available at most HVAC stores and even Napa. I'll need a minute to pull up some fan motor part numbers.

[patticake]

Also, check the motor to see if there are oil caps on the ends(for the bearings). Mine has them, is the reason I say this. Then check in the area where you are parked to see if there is a place that rebuilds them. It sounds, to me, like the bearings are going bad. You can remove the motor, take the end plate off and check the bearing. Might not have to completely remove the motor to that, with the outer bearing.

[Ron from Big D]

It is not necessary to drain the coolant in order to replace the fan motor. You can get a replacement motor at any appliance parts house. Many home appliances use this same motor.

R.E. Marabito, Dallas, TX 92WB40

[mrkane]

(07-31-2013 23:31)Ron from Big D Wrote:  It is not necessary to drain the coolant in order to replace the fan motor. You can get a replacement motor at any appliance parts house. Many home appliances use this same motor.

R.E. Marabito, Dallas, TX 92WB40

Ron:

Once the motor is in hand, a replacement condenser motor should be available, if there were any parts houses in this area. Do you have a reference for GE motors which would give the shaft diameter and length?

As shown in the picture, the fan shroud sits on a plenum over the radiator. The bolts holding the plenum to the radiator are fairly accessible, but the hose prevents sliding the fan out as a unit with the plenum attached to the shroud.

I cannot yet tell if I can reach the bolts on the back of the shroud to separate it from the plenum. It will surely be easier if they are accessible, and in that case removing the hose might be unnecessary.

(Doing any repair work is usually forbidden in RV parks, consequently I will need to perform the task elsewhere, and quickly, to avoid unwelcome attention.)

--M.R.Kane
1987 PT40 'Sleipnir'
currently Iron River, MI

[patticake]

I was going to say for you to come by the house, but then I saw that you were up in the frozen north, so....... never mind

[mrkane]

It turns out the shroud-to-plenum bolts were accessible on all four sides after raising the coach so I fit underneath. Thirty years ago, I might have been able to just snatch the assembly out, but I'm much too dignified and mature* to do it now. Will have to construct a lifting device.

The motor is a sealed unit, ~5 5/8" diameter, and the shaft extends about 9 inches. Still haven't found a comparable one online.


--M.R.Kane
1987 PT40 'Sleipnir'
currently Iron River, MI


*code words for 'too fat and out-of-shape'

[davidbrady]

Hi M.R.,

I think you need something like the Dayton 3M957 although Grainger says it's no longer available.

Grainger lists the following two motors as alternatives: 3LU80 and 4M099.

If you can give us all the specs that are on the tag on the motor (or a pic of the tag), we can help you find a replacement online.

[mrkane]

Just back from only local vendor--nothing in stock. Call to Grainger not helpful: 4LY88 suggested, but capacitor interferes with current mounting. Those you list are not shown as sealed motors.

This is tag on the motor:



--M.R.Kane
1987 PT40 'Sleipnir'
currently Iron River, MI

[davidbrady]

Here's your motor. It's also on ebay.

None of the Powertech generators in our Birds use enclosed motors; I'm sure you'd be fine with an exposed winding motor. If we can find some dimensions for the 5KCP39LGS8 we could probably match it up in Grainger's product line.