I think what product to use has been covered well enough, but I wanted to relate a weatherstripping story:
Bought a brand new Honda van several years ago. After about 20,000 miles, the sliding back doors seemed to have welded shut. You couldn't open them things for the life of you! Turns out Honda's supplier made some batches of weatherstripping that failed to have silicone in the mix. They rely on silicone inside the "rubber" matrix to keep it lubricated so that it won't seal so good as to keep the door from opening. My short term solution was to spray silicone lubricant on the rubber. The long term solution was to bring the (*#&$(*# van back to Honda where they removed the doors and replaced the gaskets.
Bill
