Click on the "FAST LANE" tab at the top of this page. Enter your year/make... then selech your model. The _Catagory_ is "+Fuel Injection" and the part is called... "Water Temp. Sensor"
or just click this link
http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1OH0MY2181OH0MYQHF&year=1988&make=MB&model=300-TE-001&category=C&part=Water+Temp.+Sensor&appEngines=_any
Your existing sensor should be tested for proper resistance before it is replaced (no need to throw dollars [though not too many in this case] away unnesessarily)
Should test as follows:
Ohm's range from the temp chart in the /Engine Manual-Combustion Manual-07.3 Mechanical/electronic gasoline injection system (KE injection)-121 Testing electrical components of KE injection system. page 60
Temperature °C........Resistance kΩ
-20........................15.7
-10.........................9.2
0............................5.9
10...........................3.7
20...........................2.5
30...........................1.7
40...........................1.18
50...........................0.84
60...........................0.60
70...........................0.435
80...........................0.325
90...........................0.247
Same resistance values apply to KE intake air temp sensor.
I think this chart applies to these 2 sensors for all KE systems but don't know for sure.