What is the proper operating engine temp for a 1991 560 SEL? Normally, it sits at 80 degrees, but in heavy traffic it will climb to 100. Is this normal and OK?<br> <br> Thanks
I think the temperature that you are reading is fine. Mine sits at a little over 80 degrees Celsius. Remember that at 100 C water boils. In the case of a car coolant the antifreeze moves the boiling point away from that treshhold. I would worry about the temerature if you see the needle in the guage quickly heading towards the red zone.<br> Make sure that you have a working thermostat. I am saying this because when I replaced mine about a month ago I discovered that the mechanic that touched my car befor had cut the inner core of the thermostat just so it can sit in the water pump. After that discovery, I now make sure that I am involved in every aspect of the car repairs. There are too many incompetant mechanics out there (there are some good ones, and they come at a premium).<br> Keith, the temerature that you read is importnat not only to monitor overall engine temperature but it also indicates if your engine will be running rich or lean. This helped me found what caused many of my problems that contributed to my failing emissions. I had excess hydrocarbon reading because the car was running rich.<br> The thermostat plays a large role in telling the engine to adjust its fuel to air mixture ratio. Aside from that check your O2 (oxygen) sensor by reading it's impedance with an Ohmmeter. If it is out off wack just like mine was, replace the sensor.<br> Good luck Keith
I too have a 1991 560SEL and though I have not owned it long I find that temp remains around 80-85 virtually all the time unless I am in heavy stop and go traffic and then mine also climbs to around 100 and quickly goes back down to the 80-85 range when the traffic begins moving briskly again.
. . . for these engines, I've been told by various mechanics (and have read on boards like this), is 87 degrees C. The needle ought to rest just a little above the 80 degree mark on the gauge, nearly all the time. This temp, I understand, is necessary to let the engine reach the proper operating temperature for efficient combustion. My 420SEL -- in New Orleans summer heat, with A/C on, and in slow traffic -- never edges beyond about 90. <br>
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-- The BenzAdmiral ('86 420SEL, anthracite/lt. grey; 'The Tirpitz')
my 500sel when moving is about 90°c,but once i am in traffic in Lagos Nigeria in the afternoon,where the temp is very hot,the needle jumps to 110°c,but i dont use any coolant.once i start moving the temp drops back to 90.
Holly molly 'Benz Admiral', that's impressive. I use to live in New Orleans and I know how hot a car can get there...in traffic, with the a/c on. That coolin' system gotta be in perfect condition.<br> <br> Mines, it runs right in the middle, but in traffic, with the a/c, it climbs. It usually doesn't go near the red, but it gets warmer than I'd like to see it get. The a/c even gets warm sometime(may need a charge), so I put it in neutral so it can idle up a lil. That usually helps a lil. I'll have to get it better, especially if I plan to move back there. :)
. . . it was sunny (''Oh, I wish it would rain''), outside temp about 90 and humid. I didn't have to wait at many lights during my drive home, but when I did I saw the temp needle just a little ways below the 100 C. mark. At least, I guess that's what it is -- the mark next above the 80, right? (I grew up with Fahrenheit and just can't seem to get this Celsius stuff. . . .)<br>
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The BenzAdmiral ('86 420SEL, anthracite/lt.grey; ''The Tirpitz'')
Sometimes my 500SEC will run up towards 100 soon after starting off, if I'm moving quickly on the motorway. Then it drops real quick back down to just above the 80 degree mark (I think 84 is the temp specified for my model).I put this down to the actions of the thermost opening as the coolant heats up. It will then rest at it's 'normal' temp for the rest of the journey, however long. It seems that this is the norm with these cars.
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