"Jumpy" fuel gauge/coolant light
 

Once I get past 1/2 tank the needle on my fuel gauge starts to intermitently jump from 1/4 tank back up to 1/2 tank.

Also: my coolant light came on yesterday, so I check the coolant. It was a bit low so I put some water in. The light is still on. Temp seems to be just a bit higher than before. Is this a sensor malfunction?

Any thoughts/insights?

Gas gauge
 

I am experiencing the same thing with my gas gauge in my '90 300E. I think I might have the fix for this. Take out the instrument cluster from the dashboard, and then take it apart. Inside, to the right and behind the gas gauge on the circuit board is a small relay. The contacts on mine were dirty/corroded from age. Take that apart and clean it (i did it with sand paper and alcohol) and then put it all back together. I cannot tell you if this is the fix because I just did this procedure tonight and still have yet to put the instruments back in the car (I am in the middle of replacing all the vacuum servos behind the dash and will not have everything back together until probably tuesday). If you want to go ahead and clean the relay and try it out, that is great, but I can also get back to you early next week when I have put my car back together. -- Mikey

Do a search on the fuel sending unit and you will find the information on your jumpy fuel gauge. It is supposed to be a relatively easy fix, however, I have just learned to live with it.

Thanks. I'm going to Mr. MB Motors (Ashman referal) tomorrow and will have Enrique check it out.