Just for your peace of mind, try changing the VDO temp sender and also check the earth of the vehicle, these two have been known to give heartburns on these vehicles from time to time.

__________________
99 Gurkha with OM616 IDI turbo

2015 Gurkha with OM616 DI turbo

2014 Rexton W with OM612 VGT

For you folks who are unfamiliar with British English......Earth is Ground in American English.......makes sense though, block ground would have an effect on the reading of the Temperature sensor.....

I just changed my Thermostat a couple of days ago......because I had begun to notice that my temperatures were increasing from a base of 95 C about 4-5 degrees or so when going up a long hill.......I paid high dollar for an official MB part from the dealership, because I wanted to know, absolutely that my thermostat would be operating in it's proper temperature range......now car runs at 90 C, but still fluctuates when going up a long hill.....

SB

__________________

Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG

This makes a lot of sense. I think my car has some funky electrical issues anyway. Will do this. Thank you. Does the speedo work electrically as well, or is it purely mechanical?

Shorebilly - Thank you for the tip. I got the Behr tstat from Phil. is that what you got from MB as OE?

dd

__________________
-------------------------------
'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

The OEM part had a BBE (I think) mark on it......bid not say Behr or any other company that I am familiar with......did have the star and the part number stamped into it......cost me $25.00 and because I decided to do this project to the MB spec....I also paid $19.50/gallon for MB antifreeze.....have not added the new antifreeze....yet.....am still flushing the old, improper, green stuff from the system......need to run over to the dealership and get a new radiator drain plug, today......old one broke, partially......it's plastic with an "O" ring.......still works, but I want to feel secure......so I have filled, run the car, and drained the radiator 2 x so far.....when I do refill with the proper antifreeze, I will use distilled water to top up.....my well water has a good bit of calcium in it, and is mildly alkaline......

SB

__________________

Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG