Fan, clutch and water pump

[jaguarjoe]

As we know, the bearings die in the clutch which, in turn, causes the water pump bearings to die. It seems to me that if the fan was out of balance by even a slight bit, that would obviously be bad for the clutch and pump, probably bad enough to wipe them out.

I think that if you spun the clutch and pump without the fan, they would run for a very, very, very long time. A balanced fan would not contribute any radial force. That would seemingly remove the burden on the clutch/pump.

Are there other fans that are better than the mass produced plastic part that we have now?

 

[Wooluf1952]

IIRC, the '08 went back to the thermo fans and got rid of the weight from the fans we have.

 

[jaguarjoe]

This may not be the definitive answer but Rock Auto lists the same part number for both 02 and 08 fans.
Summit has Flex a lite fans for this 360 but are they any better?

I have a 2 speed e-fan from a mid 90's Mark VIII. It's big and powerful (IIRC, 36 running amps, ~300 or so start up amps in high spd) Maybe it'll fit.

What codes are set after the clutch is shi* canned?
Can I fake the PCM by plugging in a fixed resistor into the harness connector that has the same ohmage as the clutch coil? This worked on my F150.

 

[Playsinsnow]

P0495 is the fan clutch code I believe. I don't know if I would try to fake the code, just replace it. know my fan was making the "whoosh" turbo charger sound, no codes-replaced water pump after checking pulleys and all is good!

 

[The_Roadie]

This may not be the definitive answer but Rock Auto lists the same part number for both 02 and 08 fans.

The fan blade assembly may be the same but the clutch is different.

Can I fake the PCM by plugging in a fixed resistor into the harness connector that has the same ohmage as the clutch coil? This worked on my F150.

No. There is a Hall Effect RPM sensor built into the clutch so the PCM can detect if the ACTUAL fan RPM matches the COMMANDED fan RPM. That's very difficult to fool. Efan users get that diagnostic removed from their PCM by a modified tune.

 

[jaguarjoe]

Dang, foiled again!

The command RPM, the clutch RPM and the comparator that throws the flag are prolly buried deep in the PCM where no one can go.

By any chance does the clutch run at a constant speed? A little uP could fake that.

 

[The_Roadie]

By any chance does the clutch run at a constant speed? A little uP could fake that.

The clutch can't run at a constant speed because it's hooked to the water pump, driven by the serpentine belt. The PCM doesn't engage the clutch fully for cooling until the ECT is above 230-240 degrees or so, but then it will call for the clutch RPM to be closer to the water pump RPM. I actually don't know the pulley size ratios so I don't know what engine RPM corresponds to what clutch RPM. But you're right - with some signal conditioning to simulate the Hall Effect sensor's output, you could come up with an analog circuit to change the fan clutch command signal (PWM) into a small signal like what comes out of the RPM sensor.

Or you could do what the tuners do - just remove the PCM's ability to use the fan clutch error code to light up the SES light and throw a visible code.

 

[jaguarjoe]

When I asked about the clutch running at a constant speed I meant the fan blade side when the coil is energized ie-it's not a PWM kinda thing.

Tell me if I'm wrong-
Engine's cold, fan loafs along w/clutch de-energized.
Engine's hot, PCM energizes clutch. Fan runs at some fixed ratio to engine speed (set by pulley ratios).
Hall sensor sends feedback to PCM saying that the fan is at speed. PCM is happy.
Fan runs until engine cools a bit then clutch drops out.
Repeat a few million times then get pissed 'cause your low bid OEM pump only lasted 10 years.