nrussell

Any pointers on how to get this joker off of front of motor? It's not cooperating.
Thanks

BigIron70

Hope this helps you,
DIESEL ENGINE


CAUTION: The electronically controlled viscous fan drive is vibration and impact sensitive, especially at the electrical connectors. Do not drop the unit.


CAUTION: If the electronically controlled viscous fan drive is replaced because of mechanical damage, the cooling fan blades should also be inspected. Inspect for fatigue cracks, or chipped blades that could have resulted from excessive vibration. Replace fan blade assembly if any of these conditions are found. Also inspect wiring harness and connectors for damage.


1. Disconnect the battery negative cables.
2. Remove fan shroud-to-engine bracket nuts.

CAUTION: Do not remove the fan pulley bolts. This pulley is under spring tension.






3. Disconnect electronically controlled fan clutch connector at lower fan shroud bracket.
4. Remove fan drive wire harness-to-lower fan shroud bracket mounting bolt.
5. Remove fan drive wire harness support from fan shroud.
6. The electronically controlled viscous fan drive/fan blade assembly is attached (threaded) to the fan pulley shaft. Remove the fan blade/fan drive assembly from fan pulley by turning the mounting nut counterclockwise (as viewed from front). Threads on the viscous fan drive are RIGHT-HAND. A 36 mm fan wrench can be used. Place a bar or screwdriver between the fan pulley bolts to prevent pulley from rotating.


NOTE: It may be necessary to loosen the top two fan shroud brackets. Removal of the engine mounted fan shroud brackets is not necessary unless removing or installing the engine.
7. Collapse fan shroud toward front of vehicle and remove fan drive/fan blade and fan shroud as an assembly.
8. Remove the six fan blade-to-viscous fan drive mounting bolts.
9. Inspect the fan for cracked, chipped or damaged fan blades.

Nsomniac05

Thats it in a nutshel except for the screwdriver instructions, I used a barring tool made for a HMMMV. The naturally aspirated AMC version of the Duramax have the same style electric fan. A tool like that will keep you from gouging your componets during removal.

nrussell

Thanks Bigiron70. I have been told I can rent/buy fan clutch tools at local auto parts stores(napa,autozone,etc,). I will have it off tomorrow. Thanks again

BigIron70

Remove single bolt (2) which holds wiring connector at the bottom of shroud, disconnect connector and pull loose from shroud. You need to squeeze release lock to disconnect connector plug. If it won't release easily spray some WD40 on it, that will help to release lock. Remove shroud with the fan clutch, also protect radiator from damage when removing fan clutch with a piece of cardboard. Be careful since edges of plastic fan are sharp. Wear gloves to protect your hands. I also remove belt from pulley, it's easier to spin pulley when removing and installing using other hand to hold fan from dropping. Less chance of damaging threads if not started properly. I have changed many of these fan clutches by myself, but if you havn't changed one before have a helper nearby just in case. When tightening I usually use my fan wrench and a few hits on the end of wrench with hammer will tighten it up enough. Install connector and bolt as before. Spin fan by hand it should not contact with wiring harness there should be plenty of clearance.

nrussell

I finally broke it loose. I rented fan clutch tools from Oreilly's and borrowed an air chisel clutch fan removal tool from local dealer. Neither one did the job. So I got out ol' faithful (3# sledge) and whacked the 36mm wrench and it finally gave loose. The springs and cam are in. I broke the cam in by holding 1500-1800rpm for 20 minutes and drove it around gently for another 30 minutes. Can I test it out tomorrow or should i take it easy next few days? I want to know if my fluttering/popping is fixed.
Thanks for all the pointers