2001 Disco - engine revving high when fan turned up past level 3

[robrover1]

Hi All,

Just new to this group and hope to participate in a regular basis!

I am having a problem with my 2001 Disco.
When I turn the fan setting on the two highest "bars"( (level 4 and 5) the engine begins to rattling and revs at a very high rpm. This does it in heat or A/C.
Thinkiing it may be an air issue but installed a new air filter and same result...any ideas at all????

Thanks!
RobRover1

 

[Disco Mike]

Be more specific, what is your normal idle, when at operating temp, what does it rev up to and what sort of noise and from where?
How many miles on the truck, is there a check engine light on, when was it last tuned and what octane gas do you use?

 

[robrover1]

Mike,

Thanks for the reply.
The RPM's are not a factor in this problem as it doesn't rev up at all when I raise the fan speed. The noise is a combination of a loud vibration and rattling coming from the bottom of dashboard area. . As soon as I lower the speed on the fan it dissapears.
There are 89k mi. on it and no check engine light is on.
It was tuned up over the summe and runs excellent. Always run this Disco on 89 or 91 octane.
Any ideas you can provide would be great!
Thanks again!

 

[alzerom]

You have broken or chiped one of the fan blades and it's out of balance. Remove the fan and balance it up if the chip is small. Since it's only obvious on higher rpm's then the chip is probably small and removing a small piece of opposing blades won't decrease the fan efficiency by much (? less than 2-5% ?). You will make that decision when you get it out. One more thing, remove the other foreign body that chipped the blade in the first place... dead mouse?

 

[robrover1]

Sounds like a plan Mike.
How easy/difficult is it to get to the fan blade?
Thanks!

 

[alzerom]

Someone else may know how to get it out without removing the dash... Seems like I remember someone doing it. Perhaps they will pop in. Otherwise plan on a break for lunch ! -david

 

[robrover1]

I'm all set now, thanks for your help Mike/David!
It was a 10 minute job.
Removed the kickpanel cover from under the glove box and them removed three screws form the bottom of the fan motor. The white round fan wheel dropped right down and was hollding a 5" piece of screening that broke off from the strip of screening panel located on the outside firewall just under the wipers. Sorry, no mouse this time!

Best,
RobRover1

 

[Disco Mike]

I misunderstood your thread, when you mentioned that the engine reved up.
You either have dirt of leaves sucked into the blower or a broken blade, as already mentioned.
Gp to my signature section and use the Rave CD, shop manual link to down load all the information you need, it is pretty easy.