Today I pulled about a ton of gravel & sand in a trailer in hilly country with the ambient temperature at 36' C ( nearly 100' F).

I am amazed that the temp guage did not alter from the 92' C setpoint whether negotiating a hill or on the flat. This is my first MB & on all previous cars the temp guage varied depending on load , ambient temp, whether the A/C was operating,stopped in traffic ect.

All I can say is that the guage is fudged OR the fan & thermostat are very efficient in operation . The radiator must also have more spare capacity than other cars.

My vehicle is a 220CDI

I welcome any comments.

 

Could I ask a simple question. Does everyones W 204 engines temperature guage remain steady at the operating set point or does it vary under certain conditions?

 

I haven't placed as much load on my car as you have but I have noted that the gauge stays rock steady once up to operating temp.
I do however think this gauge is the most "responsive" of any car I have ever owned. When it is cold out, you can actually see the gauge dip just a little just as the HVAC vent air temp bumps up during warm up. I have never had a car with a gauage sensitive enough to actually show when the thermostat opens...I guess we still have an "old fashioned" theromstat??

 

Mines do fluctuate a little bit, it goes up pass middle point and sometime goes middle point then back up pass middle point again and stays there. I ask my SA and he said a lil fluctuation is normal, as long as it not going crazy.

 

For me temp climb to 92 as car warm up, and go down to 85 when hit highway on cold days.