Date registered: Jan 2013
Vehicle: 90 350SDL, 98 S420, 97 SL500, 94 S420, past owner of W108/W112/W114/W123/W124/W126/W140 & W220 cars
Location: Tampa, FL
Mentioned: 8 Post(s)
Quoted: 605 Post(s)
I would definitely use the highest temperature rated hose I could find.
This was an especially problematic issue for these model years, and a good reason to avoid them at all costs.
All of the little fuel injection lines will go the same way as the vacuum lines, so if you're on a line replacement binge, might as well do those, too.
As for the cats, you could remove them and put straight "test" pipes in…not sure what ramifications that might have as far as the EPA or your local or state inspections, if you have them.
I live in Florida and have seen lots of these model year SLs. The engine compartments are simply toast as a result of the outrageous under hood temperatures.
I discovered this some years back when I was considering the purchase of a W107. When I found out about the model years with the under hood cats, I immediately eliminated those years from my search…