most anti corrision warrenties expire @ 3yrs because the garage never does the compulsary 'inspection' and doesn't tick the box fill out the form etc.
I know our local fiat garage is notorious for not doing it, you actually have to ask!! and even then it could be beyond the deadline
mine is OK, as previous owner took it to fiat garage for so much as the windscreen washers running out , quite impressed with it really! only rust on the whole car was the battery tray (now replaced with a cleaner item, that I then stove painted just incase! ).
ANd for anyone buying a merc don't bother, our W red (yes thats Y2k) E270Cdi estate (elegant, but with cloth interior ) had what looked like lacquer peeling off the rear left 3/4 wing, garage we bought it from (Lloyd BMW/Volvo of cockermouth ) said it was just lacquer and there would be no problem (can't see underneath as theres a plastic arch liner), they MOT'd it and tax'd for 6month as is std practise. and when it got to its first mot in our ownership it failed on RUST!!!!! There was some really weak metal under the wheelarch (within xxcm of suspension pick up ) and the garage actually showed it to us and pushed a large screwdriver right thru it in several locations AND then asked if we would like to see the inside of the other RIght hand wheel arch! JUst the same!!! and the left 3/4 had surface rust on it by this stage.
Absolute pigging disastor!!! Apparently with mercs you have to pay extra for galvanising before aug2001 And our didn't have it.
Still had a 7year anticorrosion warrenty (car was 3y and 6months old at that point), but was invalid as the inspection hadn't been done at 3years (doesn't say anything in service manual, 3years was about 5-6months into our ownersip).
ANyway, merc UK weren't interested, Lloyds actually tried to blame us , but after a few days of arguing they took the car back @ the price we paid for it <less usage (we paid £20,559 @ 18,000 miles, they bought it back basically a year later at £18,500, and they would have sold a 4year old mode At about £19000)l
Upcome of the storey, 1) don't buy a car from a dealer, 2) don't buy a <sep 2001 merc 3) don't bother with new cars atall they all suck in one way or another, AND having a new car means you have to put up with a dealer for 3years and TBH the only nice dealers are Ford CG dealers (my uncles one, and he gets all the top end models to play with, he's getting a discusting yellow Focus Mk2 ST in a few weeks , he wants a plain black one but even he won't be able to get anything than th std colours), oh and some cittroen/peugeot dealers are friendly.