Now that the cold winter days are here I am questioning the long warmup for my ML-320.
It takes about 4 miles or more to reach 80 degrees C, but it does get there and stay there. The only observation is that the gauge moves up slowly and evenly.
Last time it was in dealer they told me there wasn't a problem. Anyone else from the cold northeast confirm or should it warm up faster??

I think 4 miles to warm upfrom 20 degrees is about right. On some days when it's -4 it doesn't even get to 80 until after about a half hour. Average daytime temperatures here range between 5-20 degrees.