Yesterday I took reading off T-Stat housing and had low 80C ratings (Mid 80's weather) while factory gauge reported 100C! I am less worried now about overheating but did order a new temp sender after cleaning old one with no change. I also ran a new ground in instrument panel which did not affect gauge but did relight my tach side lights finally. Has anyone on this site had a positive result after installing new temp sender ('82 300sd)? If sender does not work, I may find a donor gauge somewhere and see how that goes - all grounds were also cleaned and tightened on this car as well . . yes, I am obsessing . . .