There was a huge traffic jam while I was on the freeway this morning. Traffic was snail-paced and outside ambient temperature was around 68F according to my car thermometer. Well, my car running temperature is usually 80-85F but most of the time it's near the 80's mark. But today, because of the stop and go traffic, my temperature rose to 90F, (I think it's 90F; it's the white bar between the 80bar and the 120bar). Is 90F considered a safe operating temperature? And is this normal for a 1990 190E 2.6 to operate at this temperature range? By the way, once traffic cleared up, car temperature returned to around 80F.
Also, regarding the coolant, if I add water, my questiona are:
1. What kind of water (e.g., tap, distilled?)
2. Do I pour it in the coolant resevoir?