w124 200 Coolant light

[cemt]

Hi Guys

I have a '86 w124 e200 auto. The coolant light stays on (orange). The Temperature level stays below 90deg(half way line) but does go up to the next line if i'm in traffic. It does return back to the half way line wen i'm out of traffic.

Water level is same, doesnt seem like theres any leaks in the system.

Oh recently i noticed a squeeky noise from the engine which i suspect the fan belt, wen idling the fan seems to be slow...

Any suggestions what this could mean?

Thanks
S