Forget keeping them out
Learn how to clean the roof A/C
Coleman: Remove 4 screw/bolts
Lift cover
peal off seeds
Replace cover and bolts
Other makes
Remove 10 screws give or take a few
Lift cover
Remove more scres or cut tape and bend tabs to remove inner over over condenser
If you have size XXL hands remove fan
Clean
Replace everything
I LIKED MY COLEMAN
oh one more thing about coleman.. Fresh cleaned I had to pay serious attention to tell if it was running or not (Stand directly under it and listen hard)
Dirty it Whomp whomp whomp ed to let me know "Clean Me"
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times