My 98 disco water pump busted on the highway. The shaft broke and the fan and fan clutch fell off. I had just replaced the starter and I mistook the water pump rumble for the heat shield rattling on the starter otherwise i would have replaced the water pump BEFORE it disintegrated . But I digress......

Since the fan lost 3 blades in the process, I put a new fan on and a new water pump but now the fan is turning all the time whereas it used to disengage at high rpm. It's an annoying sound!

Not sure how the fan clutch could have been damaged in the mishap and it looked just fine. It was replaced only about 6 months ago.

So I inspected the heat sensitive coil on the clutch and see no problem. This leads me to think the fluid coupling device is damaged somehow but how could the fluid coupling device be ruined? Isn't it just a silicone type fluid inside in a sealed compartment?

Man! I hate to buy another clutch again. any ideas?

 

Boneyard. Late 90's - early 2000's Chevy 4.3 liter, I found a Blazer. Water pump is same thread as ours. I got fan and clutch for $19. Trimmed fan blades slightly. Fan is steeper pitch, moves more air.

A direct fit new clutch is from a Chevy 2000 4.3 liter Express van, w/o AC. About $70, you will have to enlarge fan mount holes slightly. Dealer one is high dollar so they can afford that nice sign.

And yes, your clutch is bad, and you are lucky it did not take out the radiator.

Many times a new fan clutch adds stress to an older weak water pump, and this happens. Pumps and clutches wear together, so when one goes, the other is ready to jump off the cliff shortly afterwards.

 

Thanks Savannah. I bought the last clutch for around 70 bucks and it's virtually brand new. you are probably right- i shudda replaced the water pump at the same time, But we scotsmen have short arms and deep pockets. Got any idea what or how the dang clutch could be screwed up by dropping off the waterpump? What the H... is in it? some super secret device that can't take a bump? And yessir.. I was incredibly lucky to have not blown a hole in my radiator.

 

I think inside you find concentric ridges (rings) that rotate near each other, and the silicone fluid couples the two halves at specific temps, the spring operated valve may allow fluid to flow in one direction, etc. Some clutch designs have the valves, some don't. The mechcanical shock of being wrenched off by the serpantine belt while stopped long enoght to shear off fan blades screwed it up. Kinda like hitting a stump with a lawnmower.

Of course, if it is six months old, how about that warranty? My parts stores look up my purchases by my phone number.

 

I couldn't wrap my head around the idea of how the silicone fluid engaged until I looked at the picture of it in the RAVE manual (p. 349) where they explain the concept really well. It's a pretty slick design except for the fact that the silicone fluid isn't permanent and eventually will go bad.

 

It is important to recognize that the silicone fluid is in fact the clutch material. And just like your manual transmission, where the clutch material is worn away from heavy use, eventually the motor power fails to make it to the rotating load. Loss of fluid is common in clutches regardless of vehicle brand, over a long period of operation.

 

Standard duty, $46
Buy Imperial Fan Clutch - 6" Thermal 215157 at Advance Auto Parts
Severe duty, $56
Buy Imperial Fan Clutch - 6" Thermal 215157 at Advance Auto Parts
Severe duty that doesn't require drilling out holes in the fan, $56

Some more detailed info on the clutches:
https://landroverforums.com/forum/di...02/#post331068

 

interesting replies. I too can't quite wrap my pea brain around the insides of the clutch. I'm going to have to take a look at the Rave manual. I hate non repairable parts! Half the fun is in taking things apart and tinkering. I hadn't thought about a warranty on the clutch. I'll have to look into that. Thanks all!

 

By the way... what do you guys think about leaving it the way it is? I noticed a slight drop in engine temp since the thing is turning all the time. This may be a good thing since my engine runs a bit hot (Maybe clogged radiator). aside form the radiator issue do you see any harm in letting the clutch be engaged full time?

 

Fully engaged means lower MPG, that is one purpose of the clutch, to save fuel. Some guys have no clutch and a metal fan. Your existing clutch is likely to be slightly imbalanced and will wear out new water pump.

Take your IR thermometer and point at radiator top and bottom of fin surface, when truck is warmed up. More than 10F difference usually means clogged up core has started, lower rows will be cooler. D1 can be rodded out, D2 is time for new rad.

If you had no fluid in the clutch, there is no power coupling front blade mount to back water pump flange. If parked over night, there should be a fluid pool that forms, and when cranked up the fan is fully coupled front to back, and fan "roars". This noise decreases as coupling decreases, from rotating force and heat spreading the fluid around. On a clutch without a valve, the expansion of the fluid provides increased coupling as the faceplate of the clutch warms up. It is like a variable speed drill and moves up to more power, but over time, not on/off/