when it rains, the t tops dont leak. however, water seeps in at the door moldings. Could petrolium jelly help with this or would it just make a mess?

Use spray silicone on the weatherstripping. Just keep applying it each day for about a week and it will bring back some of the fullness of the rubber. If the leak is underneath the weatherstrip, you could try patching it up with black weatherstrip sealant.

I recommend replacing the weatherstripping with new GM stuff.

I would replace them but im on a budget.