PeachParts Mercedes-Benz Forum - View Single Post - Another diesel use for the gasser "Economy" gauge

Jeremy5848 · #10 08-09-2008, 10:50 PM

The four-gauge panel is finished, installed in my '87 300D, and working.

Changing the three-gauge panel (originally in the '87 300D instrument cluster) for the four-gauge panel of the 1989 300E was easy. The 300E version of the instruments (coolant temp, oil pressure, fuel) appear to work just like the 300D gauges. It is plug and play.

Changing the faceplate for an older one that doesn't say "unleaded only" added a lot more work -- I would say it doubled the time needed to do the job. It also means you must find an older cluster to rob of its faceplate, one that doesn't say "unleaded only." You might prefer to simply paint out the warning with some flat black paint and a small brush. I wouldn't advise leaving it unmodified, some idiot might try to "help" you by filling the tank with gasoline ("but that's what it said . . . ).

The older faceplate must be reamed out to accommodate the plastic support piece of the newer gauge set. You could also swap the plastic pieces and leave the faceplate alone.

Routing the vacuum line to the "Economy" gauge is easy. There's a multi-hole grommet in the firewall behind the brake booster. Anything passing through this grommet comes out behind the instrument cluster. Tee into whatever line you want to monitor and pass the line through the grommet and attach it to the gauge.

Best of all, it's reversible -- if you change your mind, you can always put your old three-gauge panel back.

Jeremy