603 Fan Clutch clarification
 

I've been reading a little about my fan clutch, I have the newer plastic blade type fan but I'd like a little clarification about how to test to see if it's bad. I'm sure mine is fine but I'd like to see if mine is on it's way out, my fan has always spun down when the engine was hot, it never stopped with the motor, nor in 1-2 Revolutions, but never gets over 80*c what do you think? should I replace it or just keep my eye on it?

An engine that never gets over 80*C is a problem.

Sixto
87 300D

it hovers really 80~85*c

IIRC with a new clutch the fan roars for a few seconds with a cold start. It's a roar the aux fan can only aspire to. The fluid distributes through the clutch and the fan disengages. That's one way to check the clutch.

You could test the clutch if you knew at what temp it engages and have a way to simulate that temperature right at the clutch. You can try a heat gun but there's not a lot of room in a 124/603. You can block airflow ahead of the radiator but how do you get the engine to run hot while idling?

Sixto
87 300D

I dont hear the fan going, I dont think even the AUX fans work...

Aux fans are easy to test. For low speed, locate the AC high pressure switch on the drier. It's the pressure switch with pigtails. With the engine running, maybe AC in cooling mode as well to be sure, jump the pigtail contacts. The aux fan should come on at low speed. If not, check the resistor in the corner behind the headlight. For high speed, locate the 3-pin temp switch on the engine fitting that attaches to the upper radiator hose. With the engine running, jump the contacts on the 2-pin connector. The aux fan should come on at high speed. For further testing, there are separate relays for low and high speeds in the box aft of the fuse box.

Sixto
87 300D

What the freak? My car hangs out at 90 degrees, but if I am running A/C and driving in town, it hits 100 quite easily. What the heck!?!? And we are in the same state!

Sounds like it is time for a new radiator and to clean that A/C condenser. I also have the 606 clutch and fan using Xerex coolant.

In the horrid heat wave we had in Texas this year (WEEKS of 100°F+ with high humidity), my SDL drove in the 85-95°C area. Radiator is about four years old.

I also use the RED aux fan switch as it kicks the fan on sooner.

hmmm....I always thought 80-85C was normal

80 to 85 "C" is normal
 

Without a Load ,or climbing hills.
(or running 130MPH in Hundred degree Ambient.)

Even running at 60-70 (when I can coax my slug that fast) it's still hangs around there, Never gets really over 85 ever.

You are lucky Aqua...I have new radiator, new water pump, new fan clutch, clean condenser, and perfectly functional aux fans...still high temps! What thermostat do you have in yours?

And are you saying that yours struggles to get to 60-70 mph?

Somewhere above 80 is what I see - closer to 85 in 603s, closer to 80 in 617s. Right at 80 seems low with a properly functioning thermostat.

Sixto
87 300D