Gone Outdoors

How to Seal a RV Roof Top Air Conditioner

by Cheryl Torrie

RV rooftop air conditioners are sealed with a sponge rubber gasket. These gaskets can deteriorate over time and cause leaks. Or you may even find that the sponge rubber gasket was serviced or installed incorrectly and it caused the normal air conditioner condensation to pool and leak into the RV. Either way, adjusting or replacing the gasket to seal you RV rooftop air conditioner at the first sign of a leak will save you from spending money on extensive RV interior repairs.

Check the gasket that seals your RV's rooftop air conditioner. Visibly inspect the gasket for compression (there should always be at least ½ inch clearance between the roof of your RV and the air conditioner housing), cracks, wear, gaps, loose screws and visible caulk.

Repair or replace the air conditioner gasket. Loose screws need to be tightened. Any caulk or other sealant needs to be removed. Cracked or compressed gaskets need to be replaced. To replace the gasket, pick up or order one from your local RV dealer. Disconnect your RV from any power source. Remove the inside plastic housing. Disconnect the wiring harness or individual electrical wires. Remove the mounting bolts. Go outside of the RV to the rooftop unit and remove the screws or bolts that hold the cover to the air conditioning unit. Remove the AC unit and place it on its side, not upside down. Placing the unit upside down even for a short period can damage the coolant charge. Remove the sponge rubber gasket. Install the new gasket and reassemble the rooftop unit, interior wiring and plastic housing.

Verify that your work sealed your air conditioner. Testing that your air conditioner does not leak condensation or rain water on a sunny day by running your air conditioner and spraying a light spray with the water hose is better than waiting for a rainy day and finding it wasn't a gasket seal problem that was causing your leak.


  • If repairing or replacing your air conditioner's seal does not correct your leak, you may have a sagging roof issue that needs to be addressed. While you have your air conditioner apart, clean the coils to improve its performance.


  • Never caulk around the air conditioner. The condensation needs to have someplace to drain.

About the Author

Based in Covington, Tenn., Cheryl Torrie has been writing how-to articles since 2008. Her articles appear on eHow. Torrie received a certificate in travel and tourism from South Eastern Academy and is enrolled in a computer information systems program at Tennessee Technology Center at Covington.