Folks,
If you take a little time, and read the MB Service Manual section 20-005, you will find a nice description of the cooling system and thermostat.

Please note that the thermostat does not work like most USA ones do.....it is actually a mixing valve.....

Also note that the thermostat housing and system are designed to be "self venting".....

OEM Thermostats have a little arrow stamped into the rim/edge.....the arrow points up......

Just follow the instructions in section 20-010 and you should not have any problems.....

SB

NOTE: the MB Service manual that I refer to is for W123 models

__________________

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