How to Seal a RV Roof Top Air Conditioner

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If your RV's rooftop air conditioner has deteriorated and started to leak, it might be time repair or replace the sponge rubber gasket that seals it. Luckily, you should be able to make the fix on your own with just a few tools and simple steps.

Adjusting or replacing the gasket yourself can save you some serious stress and cash. Here's how to do it.

    Check the gasket that seals your RV's rooftop air conditioner, inspecting it for any visible compression. Do this by measuring the clearance between the roof of your RV and the air conditioner housing – there should be at least half an inch of space between them, so if there's less, take note.

    Also check for cracks, wear, gaps, loose screws and visible caulk. Tighten any loose screws you find during your inspection, and if you spot any visible caulk or other sealant, remove it.

    If your gasket inspection yielded evidence of compression, or if the gasket is cracked, you'll need to replace it. Before making the replacement, make sure to disconnect your RV from its power source.

    Once you've obtained a replacement gasket, remove the current gasket's plastic housing and disconnect its wiring harness and individual electric wires. Remove the mounting bolts as well as the screws and bolts that secure the air conditioning unit's cover.

    Remove the air conditioning unit, placing it on its side, and take out the sponge rubber gasket. Place the new gasket and reassemble the rooftop unit, wiring and plastic housing.

    Verify that your work sealed your air conditioner by testing it out. Use a water hose to lightly spray the air conditioner while it's running to check for any leaks or other seal problems. Make sure not to skip this step – it can save you a lot of grief on rainy roadtrip days in the future.


    • 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.