To save gas, not sure but it takes @ 7hp to run ta fixed fan at full speed, plus the fan is only need whebn the car is not moving.
Actually you could take it out and use the car on the interstate without overheating it, just dont do it during russ hour.

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89 560SL
78 172N
01 CBRXX
98 EV11

On the radiator Q, if your radiator neck has no steel inner liner (just pull the big upper hose and it s/b visible), and the PO used the green (or non-MB) stuff for coolant, consider replacing the whole thing.

My experience with rebuilt ones is that the re-crimped replacement plastic top starts to leak (2 data points - 300SD/1983 and 560SEL/1990) and use of non-MB coolant causes the plastic in the neck to harden and crack. Plus, many overtighten the hose clamps. Use MB hose clamps - they are slightly rounded to prevent cutting the rubber, in contrast to many non-OEM ones.

Behr makes OEM radiators - they are fairly inexpensive from Fast Lane. A rebuilt usually runs ~$100 if you pull the old radiator yourself. If you take the fan off (4 10mm bolts) you can change the radiator in <60 minutes. Put a piece of cardboard in place to prevent damage to the very delicate cooling fins for the a/c, and make sure you have the 2 rubber doughnuts on which the radiator rests - might make sense to get new ones at the age of car you have.

Thanks for all the replies.
Will consider all your wisdow as I continue to beat the old girl into shape.

Regards,

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Thanks,
Mike

'83 300D
'87 Volvo DL Wagon
'88 420SEL (SOLD)
'98 Toyota Camry SE V6
'96 Ford Brono XLT
'94 Mercury Villager
'46 Willy's CJ2A
'40 Packard 110 4DSD

"Just another squirrel, trying to get a nut"