Engine temperature affected by humidity?
Thread Starter
Member
Joined: Aug 2006
Posts: 101
Likes: 1
From: Portland Area
2000 C230K and 2002 ML320
Engine temperature affected by humidity?
It has been 80F+ and dry for the past couple weeks and my car has been running perfectly... temp at about 83-87c while sitting in traffic with the AC on.
This past week... its been 65 with heavy humidity and my cars temp will rise to about 95c while stopped at a light with the AC on... not that I am that worried about this temp as it's still below that unmarked line... but I am just wondering what is up.
And when I start going again, the temp will drop to the 80c mark... it never goes that low once its warmed up fully. but it will rebound back to the normal of a tick over the 80c mark within seconds.
Is it the humidity in the air making it harder to cool the engine while stopped and also making the engine run cooler quicker once moving with the moisture in the air?
Tell me if I'm crazy... but is this plausible? Or should I be looking at getting a cooling system flush and perhaps a new thermostat?
This past week... its been 65 with heavy humidity and my cars temp will rise to about 95c while stopped at a light with the AC on... not that I am that worried about this temp as it's still below that unmarked line... but I am just wondering what is up.
And when I start going again, the temp will drop to the 80c mark... it never goes that low once its warmed up fully. but it will rebound back to the normal of a tick over the 80c mark within seconds.
Is it the humidity in the air making it harder to cool the engine while stopped and also making the engine run cooler quicker once moving with the moisture in the air?
Tell me if I'm crazy... but is this plausible? Or should I be looking at getting a cooling system flush and perhaps a new thermostat?
Senior Member
Joined: Feb 2007
Posts: 449
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From: Florida, Tampa
1993 190E 2.6
Im having the same probem in my 190e. I havent figured out what is it. I live in florida and its usually humid out. My car will wun hot at lgihts or drive thru's. Once i start going it cools rapidly. If you figure it out, let me know. I dont think its the humidity. I even have a 167f thermo wich is like a 75c i think. and it still does it.
Newbie
Joined: Mar 2007
Posts: 20
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W202 C230k
It will be. You notice that a humid 30c feels a lot hotter than a dry 30c? Basically the water in the air has a greater ability to pass on the heat which is why if you want to insulate something you trap air because air is crap at passing on and retaining heat. Your car wont overheat when your driving because you've got a constant stream of cool air going through the engine bay. When you stop the air doesn't circulate which means the hot air stuck in the engine bay will build up to a higher temperature.
Thread Starter
Member
Joined: Aug 2006
Posts: 101
Likes: 1
From: Portland Area
2000 C230K and 2002 ML320
Yep... I have been paying close attention to the temp the past few days... it seems to be normal now that the humidity levels have dropped.
I have also played with different scenarios with A/C on and off and on max and auto and I can get the aux fans to come on with the temp at about 95... which from another thread is completely and perfectly normal... it has never gone to or over the 100 mark.
Thanks... I think I was just being paranoid having only owned the car for a few months.
I have also played with different scenarios with A/C on and off and on max and auto and I can get the aux fans to come on with the temp at about 95... which from another thread is completely and perfectly normal... it has never gone to or over the 100 mark.
Thanks... I think I was just being paranoid having only owned the car for a few months.
