My R129 always at 95 with AC on regardless of the ambient temp. Occasionally it will get up to 100 or 105 when in city traffic. Whereas my ML always at 85 regardless of hte ambient temp (summer or winter has no effects on the reading). I often wonder if my R129 is running too hot. It will be great if someone can tell us what is the optimal range of operational temps are.

95 R129
98 ML320