1988 W201 rad cooling fan free spins
 

Working on a 1988 190e, I noticed that the fan wasn't spinning anywhere near as fast as the belt was turning, it kinda just limped along. this doesn't seem right, but I haven't seen this kind of fan before (no apparant fan clutch) As the engine bay temps were low is I thought maybe there is a temperature enabled clutch so that when the engine warms up the clutch graps and spins the fan faster,,, just a guess. I just got this car and do not know if it'll overheat while idling - because the fan doesn't spin fast enough to pull any air through the radiator.

Is this normal for this fan? I could spin the fan by hand and it'll spin for 30-60 seconds from the inertia of me spinning it. I'm not used to this type of behaviour out of a fan.

Sure sounds like a suspect fan clutch.
The description says it is " magnetic ", not sure what to make of that.
http://catalog.worldpac.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1XC0ZKQX923911FBCD&year=1988&make=MB&model=190-E-004&category=G&part=Fan+Clutch

Here's what it looks like... so I guess it might be fine,,,no reason to suspect it's bad, as I haven't gotten the car up to temperature yet.

Looks the same as what I posted.
Being, that it is " magnetic ", I will assume it is an electro-magnetic device, energized by applying current to it.
I will therefore assume it could be tested by applying power to it and observe the drag ( if it engages ).
Hopefully somebody with some experience ( rather than my guess work ) will chime in.

Apparantly it's designed to engage when temps reach 100C. As I am troubleshooting the start -> idle at 2K RPM, dropto 1500RPM , back up to 2000 RPM,,, give it gas let it idle then it coughs and sputters and stalls problem:eek:

check your connector too. I just got my 190 and the wires practically fell out of the plug. I re-soldered them and good to go.

One way to test the electromagnetic fan clutch is to disconnect the two pin connector of the red top coolant temperature sensor at the front of the engine block. With the ignition off and using some heavy gauge wire, bridge the two female connectors of the plug. Switch the ignition on and try to spin the radiator fan. It should not move since the electromagnet clutch should be engaged to the crankshaft. End the test as quickly as possible to avoid overheating the wire bridge.

Normal.
It will lock at 100-105 on the temp gauge. If you don't drive it around the block first you could be waiting awhile for it to kick in.