Also needs to be Sealant you can use externally. I did take the whole filter body out completely and cleaned it all out - the only way to do this is to dismantle the bit below the window and remove the windscreen wipers - did you do that?? I asked TPS about door seals - when you open the door the plastic seal that runs the full circumference of the door is approx £43 exVAT per seal!! So I thought Fcuk em!!!! But your problem you have to dismantle the door and do the above fix.