Approximately 15% of W124 chassis cars have cracked evaporators, much
higher than normal rates. Engine has no effect on this, it's the
evaporator design. If you replace it, make SURE you get the all
aluminum one, the one with copper pipes/aluminum body is the problem.
They usually last around 200,000 miles.
However, there are a number of other things that can cause the AC to
not work due to freon leakage, notably the pipe manifold on the
compressor and the front seal on the compressor, along with failed
hoses and corroded condensers. Corrosion is a serious problem up north.
Only way to check to to pressurize and leak test. The evaporator
replacement is a PITA, but it's not that hard, just takes forever.
Knock a couple thou off the offering price for a dead AC and run with
it. Chances are it's only a leak (check for deteriorated rubber in the
compressor clutch).
I'd not pass a decent 300D with a replacement engine just because the
AC was toast.
Peter
