Bad fan clutch?

[Jimmy9190]

I have a 2001 Dodge Dakota with the 3.9 V6 and a 5 speed manual, 124,000 miles on it. Occaisonally the viscous fan clutch will make a roaring noise when the engine is cold, the noise is present for about the first 1/4 mile then clears up.

Today when I went on a 100 mile round trip I was about 10 miles from home and the roaring noise just appeared out of nowhere and the truck seemed to lose a fair amount of power. It wasn't overheating, oil pressure was fine too. When going uphill in 5th gear at 1500 RPM when I gave it gas the RPM and speed increased so I don't think it's the clutch.

At home the roaring noise is present with the truck sitting still in the garage when I operate the throttle manually. The fan was very hard to turn when I first got home and is still very hard to turn now, 3 hours later. I know if you spin the fan and it spins freely the fan clutch is bad. But I have also heard and read if the fan is really hard to move at all that is also a sign the fan clutch is bad. There is no movement or play at all in the water pump shaft, none that I can detect.

I think I have a bad fan clutch, and I appreciate any help you can offer. I can't really find a lot on the hard to turn fan symptom online.

Thanks for any help here.

 

[Colt45ws]

If its cold and staying locked up beyond the normal warm up period, I would say its bad.

 

[demarpaint]

IIRC the fan clutch allows the fan to spin easily when the engine is cold, to aid in a faster warm up. It tightens up as the engine gets hot to allow better cooling. Three hours later it should spin freely if memory serves me correctly.

 

[Kiwi_ME]

It's bad.

 

[Jimmy9190]

Thanks, I just went back out and checked again. Truck has been sitting now since about 4:30, fan is still very hard to move. I took the top half of the radiator shroud off and will get to the parts store first thing tomorrow and see if I can buy a new clutch and rent the spanner wrench set to remove the old one. By the time I had figured out what I think is wrong with it all the parts stores here had closed.

Always seems truck trouble happens on Sundays when I can't get parts, but that's the way it goes sometimes I guess. I just hope it's not the water pump or anything worse. Thanks for the help.

 

[KilgoreBass]

Those fan clutches are good for about 10 years, so I think you're due.

Test: on a cold engine, let engine run for a a minute, with hood up, turn off (this normally gets the clutch loosened up, and the fluid circulating). Fan should then turn by hand with only a little resistance. Next, with a warmed up engine compartment, check again, the fan should have much more resistance when turned by hand.

Usually the clutch will "fail" by staying too loose, not staying tight, but either is possible. The main point is the clutch should change resistance with heat, assuming it's a thermostatic clutch, and not a straight viscous one.

PS: no special tools needed for this usually, what do you need to rent?

 

[Jimmy9190]

I have to rent a spanner wrench set for the fan clutch. There are holes in the water pump pulley to insert the spanner to hold the pulley still and the set includes a 36 mm wrench to break the fan nut loose off the water pump shaft.

I think I will go with the Torqflo clutch from Autozone. It looks like it is made by Hayden and has a lifetime warranty.

 

[KilgoreBass]

Ahh, OK, I didn't need anything like that when changing the fan clutch on my S10, I see you have a Dodge

 

[Jimmy9190]

Got it fixed this morning, fan clutch was definitely the problem. The old one was so locked up I couldn't even turn the nut once I got it removed from the water pump shaft. The Autozone rental tool helped too but the wrenches in it didn't fit the nut and I had to rig some bolts in the holes on the water pump pulley and hold them with the spanner wrench to loosen the old one and get the new one tightened down. Test drive was fine and engine is back to normal now. The Torqflo clutch is as quiet as the original clutch was, I was a little worried it might be louder.

Thanks again for the help here.

 

[440Magnum]

Originally Posted By: KilgoreBass
Ahh, OK, I didn't need anything like that when changing the fan clutch on my S10, I see you have a Dodge

All reverse-rotation fan clutches are about the same- Dodge, Ford, GM. If you are lucky the big clutch nut may be loose enough that you can hold the water pump still with the serpentine belt enough to break it loose... but my luck has never been that good.

 

[mechtech2]

So far, the operation of your fan clutch seems normal.
It roars when cold until the internal fluid is dispersed.
When you are overheating, it engages again.

 

[Rhymingmechanic]

I miss being able to change a water pump or fan clutch with normal hand tools. I had to rig up the same system with small bolts through holes in the water pump pulley on a Silverado. Autozone didn't have anything like a spanner. Their computer said I needed a Ford kit, which didn't fit the nut or hold the clutch. I rented a NAPA kit with hooks in a scissor arrangement (not sure that description makes any sense) to hold my bolts, and bought a big crescent wrench for the nut.

 

[Jimmy9190]

Yeah my Dodge service manual shows a picture of the Dodge special tool for the fan clutch that looks like a scissor thing holding onto the water pump pulley and a thin wrench for turning the nut. If I had looked at it longer I may have been able to rig something with a pry bar and bolts in the holes, but I rented the only kit AZ had, I had to go to AZ anyway to buy the new fan clutch. Lucky for me I had a big ole adjustable wrench to get the nut off. I was surprised that after almost 10 years on the truck the nut came off without much effort. I bet I could have just smacked it loose with a hammer on the end of the wrench like a few others have said. I am just glad I was able to fix it myself and it didn't cost much. The new fan clutch was $49.00 with a lifetime warranty.

 

[Gary Allan]

This is the type of stuff that makes me really wonder what they were thinking when the manufacturer implemented it. Normally you can understand it from an assembly line angle... one where they're shaving fractions of a second from that time/$ process, but just what purpose did this serve??

 

[Rabbler]

The pulley is one piece with the water pump on these so they saved 4 bolts and combined 2 parts into 1. That's significant $ saving but it can be a PITA when servicing. I've bent/broken several of the holding tools trying to remove. I always add a little anti-seize to the threads when reinstalling and just snug tighten the nut.

 

[KilgoreBass]

Originally Posted By: 440Magnum
Originally Posted By: KilgoreBass
Ahh, OK, I didn't need anything like that when changing the fan clutch on my S10, I see you have a Dodge

All reverse-rotation fan clutches are about the same- Dodge, Ford, GM. If you are lucky the big clutch nut may be loose enough that you can hold the water pump still with the serpentine belt enough to break it loose... but my luck has never been that good.


Not all, my 1992 S10 doesn't use a large nut, and it's reverse rotation. It has four studs for fastening the clutch hub to the water pump (the studs also pass through the pulley), and 4 bolts holding the fan to the clutch.

Seems like a better system to me, and no special tools needed, just two wrenches/sockets of the same size.

 

[440Magnum]

Originally Posted By: KilgoreBass
Originally Posted By: 440Magnum
Originally Posted By: KilgoreBass
Ahh, OK, I didn't need anything like that when changing the fan clutch on my S10, I see you have a Dodge

All reverse-rotation fan clutches are about the same- Dodge, Ford, GM. If you are lucky the big clutch nut may be loose enough that you can hold the water pump still with the serpentine belt enough to break it loose... but my luck has never been that good.


Not all, my 1992 S10 doesn't use a large nut, and it's reverse rotation. It has four studs for fastening the clutch hub to the water pump (the studs also pass through the pulley), and 4 bolts holding the fan to the clutch.

Seems like a better system to me, and no special tools needed, just two wrenches/sockets of the same size.


Interesting- The only other reverse-rotation setup I've seen that doesn't use the "jesus nut" type mount is the dual-fan (one electric, one engine-driven) setup on the 4.0 in a Jeep Cherokee. I prefer the 4-bolt type, but the manufacturers sure don't.

 

[Rhymingmechanic]

Don't get me started. I decided to change hoses while I was doing the water pump, and think I bruised my ribs trying to reinstall the "quick connect" fittings on the heater core. Quick for the guy on the assembly line, maybe.