what does the temp. gauge measure?

[jblackbu]

I have a 85' 380SE. My oil pressure gauge is pegged and the temp. gauge does not move. My question is does the temp. gauge measure water temp or engine temp?
thx

[brewtoo]

The sensor is in the head. It measures the coolant temp.

[nglitz]

Yup. It's the second sensor from the rear of the head, IIRC. The one with the single wire connection. Other sensors send coolant temperature info to the fuel injection/ignition and another switches the fans on.

[Arthur Dalton]

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=mercedesshop&baseurl=http://catalog2.mercedesshop.com/&cookieid=1DV1D0LBH1E40QRTOA&year=1985&make=MB&model=380-SE-001&category=P&part=Water+Temperature+Sender

[abe g]

ON 1977 450sl temp guage. where is ideal temp when running between 175 and 200 farenheit settings? Thanks, Abe G

[ericgr]

convert farenheit to celcisus, I think the celcius number for your car should be about 85 to 90 degrees on average, moving from there to 100 ocassionally on hot days then back down. If you stare at it too much you'll go nuts and hit another car ;-) Think about 90 degrees celcius on average. That is the case for my 1984 380SL which is similar.

Relative to the other observation about the oil gauge being pegged and temperature off, it is likely that there is a bad ground behind the instrument cluster or a problem with that portion of the instrument cluster, or connections that need cleaning.

[jblackbu]

It ended being the wire attached to the sending unit was disconnected.
I reconnected it, and it started working.

Thanks again .this site is a big help. I may keep the 380se after all.