BoostnBenz,

You are probably right in that the black coating on the fins was not paint, but some other kind of coating material. In the end, it was more long lasting than the material of the fins as when they crumbled away, the black coating was all that was left. When I encountered this the first time, I was more disappointed by the fact that the lower half of the radiator was no longer finned than curious about what the stuff was that was left over after the fins had departed. Thereafter I just wrote the whole sequence of events off as a consequence of the radiator being affordable. With Aluminum radiators this problem is not as apparent, at least not so far.

PEH,

The same goes for the actual fin material. It was no longer apparent what the fins were originally made from, and since it had been reduced to a flaking, crumbling, mess that looked like rust, I assumed it was rust. Sorry if I mislead someone.

I did some reading on the web on the subject and it seems Copper-Brass radiators are trying to make a come back. The new units have tubes with about a third the wall thickness and fins about half the thickness of the old ones. All to improve heat transfer and save weight and cost, with a design life of 10 years. Sounds like a very delicate item to have out front in the air stream, especially up here in the Northeast with our annual sandstorm season that lasts from December until May. Hail and even raindrops at typical highway speeds might prove dangerous.

Well, good luck, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)