Here's my problem...Was driving from Vancouver to Toronto. Hit temperatures of -45 C from Alberta to Manitoba. Once I hit Ontario, it was - 35 C at 4AM and my 2003 ML350 decided to lose power. The BAS/ESP light came on them I started to lose power. Pulled over to the side of the road and the ML was running rough. Whole vehicle was shaking. Had to keep it running until the tow truck came which was 2 hours later. Took for service at a Mercedes dealer in Thunder Bay, Ontario and was told that my thermostat wasn't warming the engine enough. It was only reaching between 75 C to 80 C when it's suppose to be at 90 C and up. They told me that it was the reason and it froze my throttle. Anyway, they changed my thermostat and charged me $430 for parts and labour. Drove the ML to Toronto with no problems at all. My problem with this is, I have never heard this before. I was driving at -45C without problems and all of the sudden they told me that my engine wasn't warming up enough that's why my throttle froze at -35C? I will be driving back to Vancouver in a few days and I just hope it doesn't happen to me again. Should I be looking for another cause of the problem I encountered before I take my trip back to Vancouver?

 

Although I do not have experience with such extream conditions, I find it difficult to believe it's due to the 10°C difference. The normal operating temperature for the engineis at 88°C anyway. However, most of the electronics work between -20°C and 60°C. When it's below -30°C, it could have failed to work. May be the rise in the engine temperature heats up the rest of the electronics.