Good window sealant

I would suggest removing the windows, getting new tacky tape, re-installing window then run a small bead of sealant, like Geoflex, around top and sides. Make sure the drains are clear.
The factory may not have put wide enough tacky tape to cover the complete void around the window.

IMO a lot of different ways to seal a window and different types. And when one person says "sealant" or "caulking" that means different things to different people. But obviously the manufacture didn't do a good job.

If you're just going to run a bead of whatever around window you'll be doing it again and again and hoping you don't have any leaks when your done.

By the time you take a window out, clean up the old stuff, put on new putty tape and re-install, why cheap out on material? I do put silicon around mine but it is just a small bead or a ribbon hardly visible, and it works as an umbrella for the putty tape to help the rain along. And that also comes in handy in about 3 years because you can see where silicon starts to fall apart. And time for good re-inspection. Several RV's ago I put a little square of the brand name "tacky tape" on a fence post. I'm real impressed with the stuff. It is still pliable, I can still mash my thumbnail into it. It didn't harden and crack like the cheap stuff does. I think it has been on top fence post for over 10 years now.

There's a reason some caulking sells for $1.99 a tube at and others are $12.00 Of course you could buy some O'Henrys roof patch and slap it on and by end of next summer have gobs of black streaks running down your RV. But you can get a gallon pretty cheap for what it does.

Your in Nor CAl, ask your RV place if they use NWP (Northwest Trailer Parts or Keystone) If so, have them look up NWP part number 13-0865 or 13-0866 or 13-0867 Price is 8.59- 15.39 a roll depending on width and length. Very pleased with the stuff.

I hope Santa brings me a Go-pro camera this year. First vid I want to make a vid about RV windows. There are some youtube vids but nothing start to finish and what to watch out for.

And of course you can always believe a product works good as manufacture says it does:B Anyways I'm pleased with the stuff for windows. Other joints I use other sealants or caulking. Depends on material being joined together.
http://tacky-tape.com/products/butyl-sealants/sm5227/

OK thanks for the heads up. I have a tube of DAP at home that states it is flexible so was considering using it. I guess I'll go ahead and pick up the RV specific stuff.

Your tt will get a lot more aging than the for at a stick house
There is more expansion and contraction with temperature changes
Road vibration etc...

I never had much luck with Dap and similar home products

However a good grade of polyurethane sealant will work just as well as the name brand RV stuff
It's the same chemical composition
I buy 3M Marine grade polyurethane at Orchard..or buy regular roofing polyurethane at home depot
It's super sticky..does not Set Up as fast as silicone ..But doesn't dry out like silicone .. and it stretches with weather conditions
Buy Dicor RV..or 3M. Etc... But stay away from the cheap home products

If you go cheap you will not be happy with the results. Use Proflex found at RV places and you will be happier with the results! I used Proflex 'clear' around the windows of my Laredo and totally solved the leaking problems. However... I caution you about sealing the bottom of the windows. You need to leave small strips to drain any water that does get in... either from outside or from interior condensation around the frames.

Yes, there is a reason to use the correct product. It has to withstand the constant flexing that an RV goes through. A house doesn't flex that much so home type sealants work fine in that application. Also, those type sealants won't stick as well to aluminum or fiberglass as I found out! Use a product like ProFlex and do it once!