That thread is about a diesel fuel pre-heater on a W124.

My '84 Euro 300TD came with a mangled Euro rear-bumper and Euro-hitch installed.
Problem is the Euro-hitch only works with the Euro bumper as the hitch and it's reinforcing brackets mounts over and into the body-sockets for the US bumper-shocks.
The Euro bumper is attractive but even with the hitch, it sits very close to the body and provides minimal protection. When I purchased my wagon, the rear hatch had already been slightly deformed and jammed by a minor impact, and wouldn't open. Since the Euro rear bumper was damaged, and the car had previously been fitted with a US front bumper, I went ahead and installed a US rear bumper - unfortunately eliminating the Euro-hitch.

Happy Motoring, Mark

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DrDKW