noisy AC a/c but it's not a bearing?

[fishkayaks]

The front a/c in my 2013 36FB started making a noise in the cabin very similar to a motor bearing after 15 minutes or so of starting up. The motor is less than a year old however, spins very freely and the sound is imperceptible when on the roof with the shroud off. While investigating the sound in the cabin, I can stop it by gently pressing on the ceiling panel directly under the front A/C. It seems there's a slight vibration and I've got wires or duct work under the A/C making quite the racket in the cabin. For the time being i've placed a telescoping handle between the kitchen counter and the ceiling panel so I can run the a/c.

Today I'll pull off the MaxAir sleeve and kitchen ceiling light to see if i can access the truss and look for the culprit.

Has anyone else run into this...? Any suggestions on the best approach to troubleshoot something in the ceiling?

[homeguy]

check the mounting bolts holding the unit to the roof. Many, including myself, have found them loose or not secure in the decking.

[XCMARK]

check the fan blades to see if they are dirty, its possible that can cause more vibration then normal . The bolts in the roof is also a good tip to check.

[fishkayaks]

I'll check both fan and bolts, thanks! I'd hoped to see between the ceiling and roofing by removing the Maxair fan sleeve but it's blocked by a 2x4, no help there...

[camper94]

As a reminder, the Air Conditioners of today are basically throw away units. It will usually cost more to repair them, than it is to simply replace them with a new ones.


Just my 3 cents.

[hoosierguy]

My rear most A/C unit has been making some squealing noise for some time now. So, I decided to remove the shroud to check the motor. First issue that I ran into was that 1 of the 4 screws holding the shroud on the unit had been cross threaded into the nut that is swaged onto the underlying sheet metal. I finally had to use my Dremel tool to cut the head off the screw. The Redwood assembly person just couldn't take a few extra seconds to start the screw straight. He was so determined to drive that screw that he stripped out the phillips socket also. So, my only choice was to cut off the head of the screw. I then was able to remove the A/C shroud.

In order to repair the cross threaded nut that is swaged onto the sheet metal, it took me considerable effort with 2 sets of vise grips to remove the remainder of the screw from the nut sleeve. I then used a 1/4-20 tap to clear the threads of the nut. Of course the nut was spinning in the sheet metal, so, I devised a way swage it into the sheet metal again. So, I think I will be able to put everything back together again. 4 hours later.

Now to discover what was really making the noise in the A/C unit. That is an exercise for tomorrow morning when its cooler.

[LoSt]

I have a 2015 36FB and found that the seal under the A/C unit had compressed and slid back just a bit. I added a strip of 3/8" high-density foam under the front of the unit and the vibrations stopped.

[fishkayaks]

The noise has returned so I need to check the four mounting bolts. Do I need to remove the ceiling panel under the AC in order to do this? Apparently these bolts are tightened from underneath but there's no access due to the ceiling panel. How involved is removing a ceiling panel?

[travelin' texans]

You should be able to access those bolts from the top by removing the ac cover. You should not have to remove ceiling panels. If it's like mine the only thing underneath is the duct work & a very poor job of taping the 2 together that was mixing return air & cold air plus blowing air into the attic.
You may have to add some sort of screws or other fasteners to the noisy ceiling panel so you can remove the prop off the island.