I have a mercedes s 350d-W140 1993 year.
When I take out the wire out of cooling temp/sensor,gage does not drop
to zero.when I plug again and I drive,gage is erratic.when I top the
accelarator,sometimes it drops a litle or goes higher a litle.and the
angine temperature,goes to 180 F,BUT DOESN’T BOIL water over.when stop
feel with hands the radiator from the inside looiking at the
engine,right side is hot,left side is warm,and the lower thermostat
hose on the left side,is cold.when the uper hose on the radiator,its
hot.when you sut the car,and wait for an hour,the same upper hose is
flat,like sucking air.
those happened on a rebuild angine,and I have changed water
pump,thermostat housing,and thermostat.
I am looking forward to hearing from you soon.
Best Regards
Giorgos