Rust Blisters

I am doing a whole scale respray (DIY) at the moment.. and when you pull the insides off I suspect you will find the source of the moisture inside the car; mine had a leaking windscreen for years and the humidity level started rust in all sorts of places (like on the internal roll bar between the roof and the foam. The seams have sealant on the outside and a wax on the inside but to my mind the wax does not seem to wick/travel very well so the moisture can start in on the seams where the welding has burnt the paint off.. added to which is that the paint is not a moisture barrier.. that is what you need to wax a car for :-(

The trouble with modern 2 pack paint is that it really does not do "repairs".. you cannot blend it in the same way as good old cellulose ..so most places go for a panel by panel repair which in your case is probably one side!

1. pull off interior and get a proper rust proofing solution sprayed on e.g. Dinotrol

2a. pick around repair.
. puncture blister,
take back to bright steel, seal with self etching rust resistant primer or high zinc loaded paint,
fill back to level with rest of paint (these cars have spray filler on them from factory and it is surprisingly thick),
then redo the elastomeric seal itself (like doing around your shower tray.. just a lot more visible)..
local spray filler primer to level out little bits
then local spray repair working outwards in ever larger areas
this will never be perfect but it might be good enough for you at the moment in time while you dream up the next bill to get the real respray..

2b. Do same but whole scale panel spraying...

2c. Live dangereously.. rip car to bits .. do full windows/interior out + panels/doors off respray ... and stop using car for at least a year while you do it! :-)

I presume you mean the vertical seam on the side just above the bumper cap and behind the arches or the horizontal seam between the rubber strip and windows?

Unfortunately very common. I have a bit of rust there on mine as well. Problem is rain gets in the rear vents...

But according the the sales brochure it does come with a 30 year warranty against rust on the body... assuming you're the original owner.

I have these too in the same place above the rubber strip but then my car is 8 years older than yours, I have just touched them in after removing the bubbled paint with a dremel and then as per the advice in the e-mail build back after rust treating and touch up with correct colour. It is easier to make these look ok cos it is on a seam and not in the middle of a panel and your eye is not drawn to the repair.

P.S The mobilo life rust warranty is valid for subsequent owners but it is so difficult to prove that the corrosion was from the inside out it is not worth the paper its written on.

I had a similar thing on my SLK and the corrosion has to have come from within the metal, which is highly unlikely to happen (hence the fact they offer a 30 year warranty) ie not a stone chip on the outside or even the inside of a panel counts as the outside if it has had moisture on it . They are very obstructive with this If you had a mystery rust patch come through somewhere inaccessible from the inside and proven not damaged from the outside they might cough up lol.