Being in the sunshine belt I am not familiar with the rust profile of these cars (other than the bottom edge of rear window).
Going to look at an 80 240 that adverts as from Canada with "some surface rust". Surface rust and fender, valance, rockers probably isnt show-stopper issue. Where to look for rust that is show-stopper (financially unsound to repair)? standard, normally expected locations?

Thanks

Check the hood hinge pockets (under the hood); check the floors (remove carpets); check the jack points; check the spare tire storage well; check the left and right wheel well areas in the trunk by removing the inner black plastic trunk liner; check the cowl area.

Rust is always expensive to repair on any of the body panels, if you are indeed intent on repairing it. But some surface rust on the underside and suspension components is not a big deal. I'd look all around the perimeter of the bottom edge of bottom. Then I'd lift up carpets in all 4 foot wells as there can be huge amounts of rust there from various leak sources (AC, battery tray, window seals). Look in trunk under carpet and plastic liners too.

If you can remove the battery, look under and behind there. If you can inspect bottom of doors - rust down there could mean water collected inside of doors and rusting from within which would suck.

My car came from California and I opted to deal with significant collision damage because there was nothing here in SW Ohio that didn't have major rust issues. Sometimes they were obvious, other times they were hiding under fresh paint or primer.

Even my California car has a bit of rust by the battery tray. The guys on here told me that Benz sheet metal was not galvanized, only electrocoated, so keep that in mind.

Point of all this is that I can't imagine a car in Canada that doesn't have something way beyond the surface rust you might see in the photos. If you are in Arizona, I'd sure look closer to home.

I've learned the hard way to buy from the south or west on any car, even those made of galvanized sheet metal. Not just for sheet metal, but for having bolts come loose instead of shearing off. Just my .02 after 40 years and 100+ cars. Good luck!

There are some cars up here in Canada for various reasons that have no rust. Not too common though. There are several things going on with Mercedes that seem to promote rust.


For example if you look carefully at any surface area that has rust. You will notice the rust spreads under the paint outside the actual paint loss area. This I suspect might have been caused by the use of a non waterproof primer. They were very common for a long time and whatever variation Mercedes used was pretty non water resistant in my opinion.


A car exposed to extreme temperature changes especially dropping below freezing the metal will sweat. The bond of the undercoating on these cars traps this moisture between the undercoating and the metal. Or before the undercoating was sprayed on the metal had already developed a small amount of oxidation on the surface perhaps.


Anyways enough oxygen gets in to allow this retained moisture to really go to work of the base metal.


To me what is described as a dry southern car may have more meaning to me than others. At least get that ex Canadian car or any car out of a known rusting prone area up on a hoist and have a serious look and probe.


As the metal underneath the undercoating reverts to iron oxide on its at back to its natural state no strength is left other than the undercoat. always watch out for any form of sprayed on cover up attempt as it can be very deceptive. Another thing to consider is that car may not have spent much of it's overall life up here in Canada.


Another fact is certain areas like the Canadian oil patch area of Canada the cars have far less corrosion issues. They use no salt on the roads in winter. The upside of a Canadian car is many are not driven nearly as far in overall millage as cars I have examined in central Alabama. Plus the accumulated sun damage can be almost nothing in comparison.


What southerners call rust would be a joke to us that live in the rustbelt areas of north America. You have to actually get out and examine any car you are interested in personally.


Simply because all cars do not fit the expected profile. How many years that particular car spent in Canada and where. Plus if it was garaged as well will be reflected in what you find.

My pet peeve is cars could be made of modified steels that will not rust through for a very long time If ever. General motors did this for some time with their floor platforms where they still had no oxidation and all the panels that where attached to them rotted away.


The additional cost to build cars this way is minimal. For example anytime you see a bridge that has a slight brown patina it is probably unpainted cor ten steel. It develops a slight rust coating on the surface and the oxidation stops. It never needs painting.


Although I think it no longer really matters that much. Retaining new cars we buy for a long time will probably be too expensive now. Between the limited time parts are available and their complexity are more likely to contribute to their demise than rusting out.


For todays economy even though it makes humans perhaps the most wasteful specis of animal on the planet the economy demands it. A throwaway society basically.