the top mark on the MB cluster should be 120, it's the maximum temp the car is safe to operate at, and it should have red line next to it. I tried to find an image of a gauge to post, and couldn't.

the mark below that should be 100, and it's perfectly safe for the motor to operate there. it's hot where you are, the engine can't unload as much heat, as long as it does not get up to the 120 mark, you should be ok.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!