No, you would have been scalded by expanding coolant at 100C!

You have a bad temp "sending unit" (ie thermistor). screws into the block below #1 glow plug somewhere if I remember correctly (or is that the Volvo?).

Side of the block, anyway.

You could also have a wire grounding on it's way to the thermistor, too, or a bad guage.

It's also possible that you have a leaking coolant reservoir that won't hold pressure, they crack at the neck sometimes so there is an opening where the pressure cap seats.

A bad visco clutch will also cause the temp to rise some.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!