Originally Posted by *AL*

Morning all, this is my first post on this site so a big hello. It's a shame that my first post involves the word 'rust' but nearly all makes of cars have an area that tend to be affected. FYI i am in the southern UK so our climate is rather mixed with lots of rain and damp conditions which are perfect for rust.
I have checked both my front doors on my late 2004 XF and the RHS door is unaffected, the LHS door (passenger) does have the start of some rust and it has cancered under the paint only in a small area. Two days ago i removed both rubber strips to investigate why the rust starts and this is what i found. The rust started around the clip hole of the rubber seal and has 'cancered' under the paint towards the lower door edge. My guess is that when these strips were installed at the factory some clips scratched the paint away around the hole and this with water retention under the strip is what feeds the rusting process.
My solution as rust wasn't too bad was to use Waxoyl (clear) and spray inside the clip holes and all along the lower door edge and coat the strip the stop water retention. This spray on wax repells water and has an anti rust formula that halts rust. As rust is only under the paint if it is starved of oxygen or water then the rust will not spread, infact the Waxoyl seeps into the area that the water used to, hence halting any further rusting. Waxoyl sprays as a liquid but sets as it cools so doesn't get washed off. I've used it for years and it really does work well. I treated both sides, one side to halt any rust and the good side to prevent any future issue.
I also used Waxoyl inside the door panels when i had the door panels off. I hope this explains why some of our XFs are affected and others not so, if the set clip scrapes the paint off then rust will eventually follow and remember many owners garage these cars to protect them and the door shuts do not 'air dry' like the cars left outside, this too is a reason some rust more than others.