Rattling down the highway does more than jar an old man’s dentures. Your RV suffers too. One way those bumps and jolts can manifest themselves is in what appears to be a roof leak. But wait! Don’t think your roof is leaking from something ‘upstairs.’ It may be something that you need to fix from downstairs.
One area not often thought about: the RV air conditioner. Sitting up there on the roof, all by its little lonesome, the A/C unit is subject to vibration and rattle like everything else. And buried under the “inside cover” are bolts that hold all that machinery tight on the roof.
Those bolts, sadly enough, can get shaken (not stirred) by rough roads and vibration from running. In time they can loosen, and may first make you aware of the situation by allowing the passage of precipitation from the roof to fall into your rig. Not a happy way to spend your summer afternoon!
Over time, A/C mounting bolts can become loose and cause serious roof leaks.
Many RVers have had the peculiar soggy experience while parked under a clear blue sky. With their air conditioner unit turned on to ward off the heat, a sudden, “Drip! Drip! Drip!” from the ceiling creates a mopping panic attack.
But yes, you could also experience the air conditioner leak-effect when it truly is raining outside. If it “rains” while you’re running your air conditioner in seemingly dry weather, what’s likely happening is that condensate, a byproduct of your air conditioner doing its job as assigned, is making its way from outside, into the inner domain.
The same is true for rain. You don’t need to be running the air conditioner to have it leak on your parade. Here’s what you need to do to check—and fix—a loose set of air conditioner mounting bolts.
First, you’ll need to remove the inside housing of your air conditioner. Turn off the air conditioner (it’s best to unplug your RV from shore power, or turn off the circuit breakers that supply juice to the A/C unit).
For RVs where the air conditioner controls are mounted on the A/C unit, you’ll likely find some plastic plugs around the outside edges of the housing. Carefully remove the plugs to expose the mounting screws, remove the screws, and lower the housing.
If your A/C is controlled by a remote thermostat, look for screws around the grill of your A/C unit. Not sure which is the grill? It’ll be directly below the A/C unit—you may need to step outside and peek up on the roof.
These four bolts need to be snugged tight to keep water out of your coach. Photo by R&T De Maris
With the cover removed, locate four bolts coming down from the roof (as pictured). These bolts are what holds your roof-mounted air conditioner firmly to the roof. Between the A/C unit and the roof is a foam gasket.
You’ll need to check the tension of the four bolts that hold the unit in place. Torque them down carefully by hand until they’re just snug, then add another quarter turn. This firmly pulls the A/C unit down onto the roof, compressing the roof gasket, which when tightened correctly keeps the water out.
One more situation that could lead to the dripping of water near your air conditioner. As condensate is released by the A/C system, it falls into a metal pan in the outside unit. From there, drain holes allow this water to roll harmlessly away across your roof (and typically down the side of your unit, sometimes leaving a dirty trail). However, if the drain hole(s) get clogged with dirt, leaves, etc., the water may roll into your coach, even if the A/C roof gasket is tight.
To check for this situation, again, disconnect yourself from power, and carefully ascend to the roof. It’s best NOT to walk on an RV roof, rather, use boards to distribute your weight.
Look for screws or other hardware the hold the outer shroud cover on your A/C unit. Remove the hardware, carefully lift off the shroud, and examine the metal pan at the bottom of the A/C unit. The drain holes in the pan should be free and clear of debris. Remove any you find and replace the shroud.
Read more about Keeping Cool This Summer With An A/C
Great tips. Few consider this important information. Even dealers and inspectors often overlook these areas.
had a leak this past winter . was thinking of replacing gasket and or AC unit .
checked bolts and two were looser than the others . tightened them . no more leak .
Had a leak so I tightened the 4 bolts. Seem to work for a while then started to leak again. Tighten them again but am afraid I’m going to tighten them to much. Hard to find what you call snug.
My roof ac on my 2016 Montana leaks into my return air. Then run out on the floor. I stuffed towels up there to dry it out there was standing water. I tightened 4 bolts it helped but still leaked just a little in 1 spot. So I went and tightened that bolt 1/2 turn now it leaks real bad . AC is off its winter. I guess I will back it off 1 turn tomorrow and hope I got it .
I have a 15k Coleman ducted heat pump. No access from ceiling. How do I tighten mounting bolts?
Hello Gene,
You have 4 bolts that come down from the roof, There are located under the ac cover.
Jeff
A spring placed above the 4 bolt heads would provide a constant tension on the roof gasket rather than having to tighten the bolts periodically. I read somewhere that the bolts were to be torqued to 50 in-lbs. Springs would maintain this force even as the foam gasket relaxes over time.