Hey All,
I was wondering what the ideal cruising temperature is for a 1993 400E. I only started driving this car in the fall last year, and it stayed relatively mild. The car usually held around 80-85 degrees per the gauge. Now that it is summer and I am using the air condition I am noticing big fluctuations in the temperature. I don't know what the unlabled tab in between 80 and 120 is(100 I think), but that is the hottest it has gotten. If this is normal, please let me know, but to me it feels like it is getting too hot. When it does get this hot I normally turn on the heat to bring down the temperature, and it normally brings it back to around 85-90 degrees. I recently did an oil change and all of my fluids were at good levels. Does anyone know of some other things I could look into as to why the car would be getting so hot? Or is 100 degrees an acceptable temperature for this car to be running at in the summer with the AC on?

Ours ran a little bit warmer than that this weekend going down the interstate. It is still quite a bit from the red zone so I am not too worried. I did put a new OEM radiator in last year and the fans all seem to be working correctly. The V-8's all run hotter than the 6's.

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95 SL500 Smoke Silver, Parchment 64K
07 E350 4matic Station Wagon White 34K
02 E320 4Matic Silver/grey 80K
05 F150 Silver 44K

How hot was yours at it's hottest? What is the highest temperature you would still feel comfortable driving? With the AC on, mine basically hangs out right below 100, I would say 99. Without the AC on, I would say it is anywhere from 90-95. That is, if the dash in between 80 and 120, not the one right next to 120, but the dash right in the middle, is indeed 100.

I think thats pretty normal. If you haven't changed coolant in awhile - flush out the old stuff and put in MB recommended see if that changes it.

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Daily Driver: 02 E430 4MATIC
In the family: '03 E500 // '04 ML500 // 64 220SE

My 300E heats up to 100 and sometimes more in stalled traffic when it is really hot out, and the aux fan kicks in.

In the past, my car would generally stay much cooler - even when stopped in traffic. My fans are all fine and I suspect my rad is past its due date.

Since yours is staying that hot while cruising, I would check your fan operation and if your rad is original, it may need replacing.

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Chris
2007 E550 4Matic - 61,000 Km - Iridium Silver, black leather, Sport package, Premium 2 package
2007 GL450 4Matic - 62,000 Km - Obsidian Black Metallic, black leather, all options
1998 E430 - sold
1989 300E - 333,000 Km - sold
1977 280E - sold
1971 250 - retired

"And a frign hat. They gave me a hat at the annual benefits meeting. I said. how does this benefit me. I dont have anything from the company.. So they gave me a hat." - TheDon

Thanks for all of the input. I just checked under the hood while the car was hot and still running, and it turns out the fan isn't working. Neither of the two fans up front by the grill were running, and they obviously should have been. Before I replace the fans, I was wondering if there is anyway to see if it is a bad connection or busted fuse? I posted a few days ago about my headlights and brake lights going out far too frequently, and someone suggested my battery might be outputting too much voltage. If this were true, could this also be a part of the problem of my fans? Also, my dashboard display light is out as well. Has anyone experienced a problem like this or at least heard of it? Thanks.