Shake, Rattle, and Roll: Tighten Those Air Conditioner Bolts

As Federal Highway Administration funds get tight, the condition of America's roads reflects this budgetary bulimia: Potholes and rough roads abound, and you and your RV are the recipients. Those washboard workouts are not only hard on your dentures, but your RV gets thoroughly rattled as well.

One area not often thought about: The RV air conditioner. Sitting up there on the roof, all by its little lonesome, the AC unit is subject to vibration and rattle like everything else. And buried under the "inside cover" are four 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 situation!

What's to do? Remove the inside housing of your air conditioner and carefully check the tension of the four bolts that hold the unit in place. Torque them down carefully and live without rain another day. After weeks of frustration, and long days with the rig covered with a blue tarp, the light came on: We torqued ours and a couple of days later, Maw Nature put it to the test: Rain, rain, rain, all night long, and not a drop inside. Now the family RV tech feels like an old fool, but at least he's a dry old fool.

Air Conditioner Maintenance Part 2: Up on the Roof

In our last installment we discussed how to handle the "inside the rig" part of air conditioner maintenance. Now we move to the part of the job will take you up topside. You’ll need a sturdy ladder. As a general rule to protect your roof, don’t walk on it. This particularly applies to older rigs that don’t have a solid plywood deck under the roofing material. Best to put a "kneeler board" across the rafters and knee walk across it to reach the ac unit.

At the unit, check out the condition of the condenser fins. These little guys provide a broad surface for outside air to draw away the heat pumped out from the inside of your rig. If they’re bent, like the two photos show, they’ll need to be straightened out to remove that heat efficiently. A thin knife or screwdriver blade may help. Or you can use an air conditioner fin comb--a specialty tool that can help if the fins are not too badly bent. We once spent countless hours with a knife blade straightening out a whole mess of fins that had been completely bent over.

While on the roof, inspect the ac unit "shroud," the protective cover. These are prone to taking hits from branches; plastic ones often get damaged by UV rays. Sometimes they can be fixed with fiberglass cloth and resin--check out a boat supply or auto parts house. If you repair cracks on the inside of the shroud, the work will likely be secure, but not obvious to outside observers. A more expensive solution is installing a replacement shroud.

The shroud should be securely mounted, you’ll find screws around the bottom of the shroud that tie it to the ac unit itself. Too much zeal with a screwdriver can easily crack the shroud around the mounting holes, rendering it useless. Take it easy! Firm, but not over-torqued is the rule for installing a shroud.

Take the screws out and carefully remove the shroud. Again, make sure you have the power disconnected--you don’t want the ac unit to start up while you’re poking around "under the hood." You’ll be looking for the evaporator--it looks like a small automotive radiator. Take a brush and gently remove dust from it--if you have an air compressor, gently blast the dust out with pressurized air. Getting the dust out will make your system more efficient.

Now check out the motor. Some ac units will have oil holes, possibly covered with a rubber plug. Other ac motors are permanently sealed and don’t require lubrication. For the former, carefully remove the plug and add 3 or 4 drops of oil--some recommend "three in one" oil for the job. Over-oiling is worse than not oiling! Replace the rubber plug(s).

Put the shroud back on, while keeping the torque down to a dull roar.

Wind It Up

Now it’s time to test the system. Be sure you have sufficient power--most ac units require your RV be hooked up to at least a 30 amp service. If you don’t have the power, wait until you get somewhere where a 30 amp circuit is available. Turn on the unit and let her rip. You should have plenty of cold air delivery. Enjoy a cool summer!

RV Air Conditioner Maintenance Part 1: The Inside Job

As summer draws closer (or for those of us in the southwest, as it continues on unabated), air conditioning becomes more of a critical issue. Here begins a two-part piece on the hands-on of air conditioner maintenance. We’ll address the most common of RV air conditioning systems--the roof mounted ac unit. Exposed as it is to the elements and low-hanging branches, the roof mounted unit is prey to a lot of problems. But let’s start "inside" first.

The easiest part of the assignment is simply cleaning or replacing air filters. Check your owner’s manual to find instructions for getting the filter out of the unit--typically by removing a couple of screws and pulling a grill loose to access the filter. This filter, although cleaned in the last few weeks, is in serious need of cleaning again.


Some ac unit filters can simply be washed in warm, soapy dishwater, thoroughly dried, and reinstalled. In use, washable filters should be removed and cleaned a couple of times a month if used in dusty areas; once a season should be enough elsewhere.

Some ac filters are not washable but must be replaced. Here’s a thought: You can replace nearly any ac filter with an after-market "electrostatic" filter that is said to capture more dust and pollen than typical OEM filters. We’ve never actually tested them out, but if you’ve got twenty bucks to check the theory out, visit a Camping World store for these super filters.

While you’re working with the filter, check out your unit’s ducting. Some rigs have simple metal channels to deliver chilled air; others may use heat distribution hoses. If you can, it’s a good time to vacuum out your ducts while servicing the filter.

So much for filters, if you’re feeling a bit more adventurous, check out unit security. We’re not talking about somebody stealing your ac unit, but rather having the thing get loose and fall of your rig. An ac unit is bolted onto your rig roof top, and generally speaking, the mounting bolts come down through the roof and snug up inside the rig. Often these can be accessed by removing the inside trim that surrounds the unit. Be sure to disconnect the power before puling this trim--you may expose electrical fittings you don’t want to get your fingers into. Once you spot the mounting hardware, make sure it’s tight. Incidentally, water leaking into your RV through the ac unit can sometimes be traced to loose mounting bolts.

We'll get onto the outside work in our next installment.