Howdy
It's been a while since I had to come here looking for answers. I guess that's a good thing since it means my Rover has been pretty good for all that time. It's a 98 Disco with about 160k on it. This is a tough one because it involves a sound which can't be described well on a written forum. but her goes........

Normally when I start up the disco and take off from the driveway it will make a whirring sound that gets louder and and higher pitched as I accelerate. Then it just dies away about 2or300 feet down the road. I've never paid much attention to it as I'm sure it's normal and always sounds like that when I first take off.

but the last few days the whirring doesn't go away. It just gets gets higher and lower as I accelerate and decelerate. It winds up and then drops as the rover goes through each gear. It also does it when in nuetral....just follows the engine revs up and down.

So now when i'm cruising down the highway at 60 there is an annoying whirring, almost whining, sound to acompany the normal engine sounds. This can't be good and I don't know whether to keep driving or try a mechanic. Been a long time since I went to a mechanic but I'm getting tired of dinking around with things I don't know about. And besides..who can afford to pay for professional reapirs?

Anyone got a clue?

thanks in advance

 

I would think pulley bearing or power steering pump if it's following rpms since they drop or increase through each gear change. It's hard to say, like you mention. Where does the sound come from? Under the vehicle or engine bay?

 

That whirring sound upon start up is your fan clutch. As you said, it should normally go away within a little bit, unless its hot out. Constant whirring can mean a few things.
1) The fan clutch is seized causing the fan to run all the time. This is far better than having it seized where it never runs.
2) Is it really hot out? If so it may not stop, though at highway speeds I think it would.
3) You could have a cooling issue causing high engine temps causing the fan to run all the time. Though again I doubt it at highway speeds.
Check the fan clutch.

 

Thanks to both of you for responding. I don't think it's the pulley bearing or the power steering since it is a sound I have always heard when first staring up. It's just that now instead of going away as I drive off it is continuous. So the fan clutch sounds like a possible answer. Hard to tell where it comes from. I assume it is under the hood but not sure I can pinpoint it.

It is definitely NOT hot weather here. So I can rule that out.

Why would the fan clutch run at start up when it is a cold engine? I'm not saying it shouldn't but I don't understand why it would?? Any ideas on how to diagnose the fan clutch and how to alleviate the problem if it IS seized?

Ok..I'm out the door to look at the fan and try to pinpoint where the noise comes from.

If I come up with anything I'll post again
Thanks

 

Ok I just listened and it is definitely the fan. GOOD diagnosis FishEH!! Now....why the heck does the fan clutch engage when the cold engine is started? and Why does it (under normal circumstances) dis-engage as I drive away from my house?

Seems to my pea brain that the clutch would ONLY engage when the need arises. Not at a cold start up? But then I'm not a British car designer.

I guess my question is; by what mechanism does this thing engage and dis-engage? And how do I remedy the thing?

I can't say I've ever noticed the sound except when I start out. Seems I would have noticed it climbing some hill in the desert in 100 plus degree weather. But then I don't climb hills in a dessert very often. Mostly this Rover is in cool -cold weather.

 

The fan clutch is filled with silicone and it pools at the bottom of the clutch which engages it.. once you start the motor it spreads the fluid out which disengages it...
And its controlled by a thermostat in the front of the fan once it's warm enough it engages till your temp drops... I'm sure someone can elaborate more.....

 

Good info -thanks SSchutz. I see now how it works. makes sense too. Looks like it's not a fixable item. Guess i'm off to find a replacement part.

 

See the "Tech Section" for a new fan clutch.

 

good pointers in the tech section as to breaking lose the big nut on the clutch.
Thanks

 

Despite the modest cost for the part, and the profanity required to remove the fan nut; you are exceptionally fortunate to have a clutch that failed "locked up" and provided more cooling, than the norm for one to go wimpy on you and not cool, stressing head gaskets, warping heads, etc. Helps to use wrench to increase tension on serpantine belt (rather than release it) when dealing with nut removal. Once removed and belt is off, spin other things the belt turns listening and feeling for roughness, etc.