AC Making Weird Noise on Startup

[EarlyRiser1]

The Dometic 13,500 air conditioner in my 2004 Rockwood 5th wheel makes a sound similar to the sound of a two-cycle gas powered engine that is misfiring. This lasts 10 or so minutes after start up, and then the sound goes away and the AC unit runs fine until it is turned off. At the next restart, the sound is repeated. I replaced the fan motor many years ago. That is the only service it has had. I'm thinking about replacing the capacitor. Could the capacitor be causing the problem?

 

[appsol]

I assume you have already climbed up and removed the cover to see if there is anything obvious that could cause such a noise. When the AC on our previous Class A started making strange noises and losing cooling power I ignored it since it was almost winter. Then this spring I called a mobile tech and he found a squirrel had built a nest inside the enclosure, and branches were dragging on the blower cage making lots of noise and of course lowering the efficiency.

Good luck with your repair.

 

[EarlyRiser1]

Yes, I have looked under the cover. Everything looks like it should under there. I wish it were as simple as a squirrel nest.