Cooling temp drop
 

I just happen to notice that my 190E 2.3-16 cooling temp drops to 80 degree Celcus from the norm of 100 degree Celcus. Althought the embient temperature in New England is getting cold, but I have never notice this much changes before. Is this mean that my thermostat stuck open? or could it be something else.
This car has 180K miles and still loving it.

Alex

Alex Vantu,

I have changed my thermostat twice in 202,000 miles on my 190E 2.3-16 for this exact reason. The engine will start to run cold all the time, and it gets crummy mileage. Good Luck, Jim

Thanks Jim,

I will replace my thermostat right away.

Alex

??
 

Since when is 100 degrees C the norm? My needle typically sits right on top of the 80 mark and I thought this was normal. Other times with the AC off and in cool weather it sits in the middle of the 80 mark.

Every Benz I've driven in my family has always been this way. Is this atypical?

Thanks...

~Paul

I believe the thermostat for this car is set to open at 87 degrees Celsius. That is what is stamped on the body, and I have boiled a few in the kitchen with a thermometer in the pot just to check them.

Given the differences between one car and another, seeing the needle favor the 100 degree mark rather than the 80 degree mark is not unusual. But if the needle is on the 80 degree mark or below it after the oil temp is near 100 degrees C you have a worn out thermostat.

The "right on 80" thermostat is what I am familiar with from my Diesels, which typically run like they have an ivisible peg in the instrument on the dash that keeps them from going over 80 or 82 degrees C.

Jim