Noisy roof air conditioner on Monaco Dynasty 1998

[mexicanpiloto13]

We recently have noticed an irritating cavitating-type noise in our DueTherm (Dometic) 620315 Penguin roof air. It works great but it seems like whatever is whirling around to force the air out, needs lubrication on the ends. Its not squealing, just a sound like its uneven as it whirls around. Doesn't seem smooth like the front unit. We recently had the insulation on the roof units replaced and I thought the four attach bolts were loose so I tightened them down. Still making the noise. Any thoughts from the experts out there would be appreciated. Can something like this be lubricated or fixed, or is the unit sealed and must be replaced? We have a 1998 and regularly run the fan all night long on this unit so its had a lot of use.
Thanks! Actual model nuber is 620315321;

[crawford]

those dam mud daubers get me at less in one or both of my ac a year need to clean the mud stuff off the squire cage fan motors.

[Big_Katuna]

I hope you didn’t over tighten the mounting bolts.
There is a foam gasket that can easily be crushed.

[MountainAir05]

From the top. You can see where the bushing on the end case of the motor. If that bad and nothing else found then a new motor. If you can move the motor shaft up/down/sideways, with a lot of play then a new motor will be need. Got mine from PPL. and I drill it before installing and lube it up.

[DFord]

Muddaubers may have built a nest on one of the fan blades causing the fan to be out balance.

[mexicanpiloto13]

Very good info. Sounds like thats what it needs. How would I access that bushing? We're on the road but headed home tomorrow. Is it from the top or from inside the coach?

[MountainAir05]

fAN motor bushing needing lube, squirrel cage loose on the shaft. I lube our once a year. Had to replace one right after purchase due to the bushing was dry and worn and made a awful noise. If you do not have a hole where the bushing is , I just drill a small hole and put in the oil that way. We had the same units.