Seems like there were numerous posts on this one, but somehow i could not apply anything to my car.
Once I hit trafick (even with A/C off) within 5 -10 minutes temp. hits 100 and than slowly keeps going to 110-115. Unless i strat going fast again id doesn't drop (I suspeckt the aux fans). But.... it seems if i get stuck in trafick for a while after reaching 115 it sometimes sudenly drops down to 100, seems like something is kicking in (ether the aux fan or a termostat?).
I checked, aux fan is spining when A/C is turned on but does not spin when the tempreture is up to a 100 and over. I checked the fuses, all looked ok.
What can I look at next, I am geting desprete here. Please help

Dmitry

90' 300CE

This happened today ya'll. The outside air temp indicator was showing 107 F. I got on the interstate running 80 mph and the coolant temp rose to around 105 C. When I slowed down the coolant temp would drop down to around 95 C. I checked the aux fans and both speeds were working fine. I could turn the A/C off and turn the heater on and the engine coolant temp would drop down to around 85 C. I am considering putting a Hi speed aux fan switch in the cockpit. Are the temperatures that I saw normal in this type of heat? Does the high speed fan switch in the cockpit sound acceptable? I would rather turn the high speed fans on prior to the coolant temp. getting above 100 C. MB should have Ford truck engineers help out with their cooling - A/C system. The best A/C systems are in Ford trucks for this part of the country.
I will be installing a new thermostat and replacing the coolant tomorrow morning.

I think south Ga is turning into desert.
engatwork
'95 E320

If the temp rises at freeway speed, then drops at idle, the radiator is likely plugged internally. With it's reduced flow, it is sufficient to cool the car at low speeds, but cannot keep up at higher loads/speeds. You can have the radiator flow checked at a dealer or radiator shop. You don't want to overheat your Benz; if you do, get out the checkbook!
Colin

Great, but no one answered my question !
Is there a way i can just turn the aux fans on to work constantly for the summer period?
I can not locate any components of the fan system. Please help

Dmitry

90' 300CE

You can run 2 wires from the high pressure switch on the drier. When they touch, the fans are on, when open the fans are off. The high pressure switch is the red or green switch on the drier.

------------------
Benzmac:
Donnie Drummonds
1991 GMC Syclone
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

I found the wires and conected them together ( the ones that go on some
sort of valve on the side of the the freon canister) . Something klicked but aux fan
did not turn on. Put the wires back on, turned A/C on , after may be 5-10
seconds aux fan started working. When I unpluged one of this wires off the
presure switch something klicked again but aux fan did not stop working. The aux fan does not turn on right away when the A/C buton is pressed. Something is defenately wrong here

Dmitry

90' 300CE

sounds to me like you might want to consider having your fan clutch inspected and or replaced.
ryan