I am trying to determine whether my temp gauge might be off in my 92 300D. She is indicating a bit on the warm side, but the housing at the top of the engine, where the upper coolant hose attaches, measures 90 degrees at its hottest point with a laser thermometer. Isn't that where the coolant temps are taken? The t-stat housing, by comparison, is significantly cooler. I need to flush the coolant anyway (green stuff from PO in there), so I may run a little degreaser through and flush a few times to see if that helps.

Many thanks!

EDIT: title should read "coolant teMps," of course. Sorry 'bout that.

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1992 300D 2.5T
1980 Euro 300D (sadly, sold)
1998 Jetta TDI, 132K "Rudy"
1974 Triumph TR6
1999 Saab 9-5 wagon (wife's)

There's usually a couple of temp sensors at the upper radiator hose fitting, one or two in the head just below the injectors, and in some cases one by the thermostat/lower radiator hose fitting. IIRC the ones on the upper hose fitting are switches rather than senders.

Disconnect them one-by-one to determine which one feeds the gauge though my guess is the gauge reads directly off the head.

Sixto
87 300D