RV Roof Air Conditioner Gasket Leaks

As I write this tip it’s hot… 96 degrees… here in Gila Bend, Arizona. You can bet we’re running the air conditioner.

An RV roof air conditioner sits on a large foam gasket and is held in place by four bolts or threaded rods and nuts that go through the A/C vent to the inside ceiling frame. This mounting method isolates much of the A/C vibration making it quieter running.

Over time the gasket will compress and the fastening bolts/nuts will become loose.

When this happens water leaks, either from rain or condensation from the operating air conditioner, can occur at the gasket. Fortunately the leak can usually be stopped by simply tightening the nuts/bolts. Don’t tighten them too much, just snug them, you still want the gasket to have some give.

If you can’t stop the leak by tighten the bolts, the gasket may be damaged or just too old, so you will want to replace it.

Replacing an A/C gasket can be strenuous… a roof A/C unit is pretty heavy… but it’s an easy project. Simply remove the fastening nuts/bolts, disconnect the wiring harness, go up on the roof and lift/tilt the air conditioner off the vent… it’s easier when two people do it. And you should have someone down below to make sure wires and such don’t get hung up.

New gaskets don’t need added putty and stuff, but you do need to make sure the roof edges around the vent are clean and don’t have gouges or dents through which water can leak.

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2 Responses to "RV Roof Air Conditioner Gasket Leaks"

  1. My Onan Genset 4000 hasn’t been used (for actual electric power) for years except for occassionally cranking it up for 15 minutes a couple times every summer. It starts right up and runs smoothly, but for the last 2 years it puts out between 170 and 175 VAC. I’ve assumed it’s the regulator, but now I’m thinking it might just be some dirt/corrosion, etc on the commutator. Last time I checked, a regulator was slightly less than $300, so rather than arbitrarily just ordering one, I thought I’d throw out my problem and possibly someone has some advice. Thanks in advance. BTW, my RV is an old 84 Tioga, which still gets around just great with its 50,000 miles. Thanks again.

  2. If your recreational vehicles (RV) air conditioner is leaking, then it is probably time to replace the rooftop gasket that seals the unit. As this gasket ages, it becomes brittle, hard, and unable to seal the opening, thus permitting moisture to enter the RV. Replace an old gasket with a new one and eliminate a frustrating air conditioner leak.

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