In doing a search, it appears that the CPU cooling in the 8400 is done 
via a shroud with a fan built into it. I don't know if the fan can be 
removed and replaced separately, but the only sites I found selling a 
replacement are in the UK and include the shroud, fan and mounting 
hardware as a package for about $50 USA plus shipping. Dell likes 
proprietary components so you might contact them to ask about a fan 
replacement from them.

Sorry I can't help any more than this. If the fan itself is removable, 
you can likely do an on-line search for it using any ID info on it. At 
least you do not have to disturb the CPU.

Tom

Donald DeWitt wrote:
> You were correct; it may have been a fluke. The first day was the warning
> message.The second day I got a message reminding me of the warning. To date,
> I haven't had any since. The fan is apparently running ok. However, I
> believe I'll do what you recommend and have a spare here just in case it
> dies altogether. I believe I can replace it ok but not sure how to order a
> new one. When ordering a replacement, are they identified by size, by brand
> name, voltage or some other ID? This should be a stock factory installed
> Dell part.
>
>
> Many Thanks for your input,
>
> Don
>
>
> On Fri, Jul 4, 2008 at 12:20 PM, Thomas Mayer <[log in to unmask]>
> wrote:
>
>   
>> My first thought is that their was a one time error in getting the message.
>> I would consider three options:
>>
>> Keep using the computer and see if it happens again.
>> Keep using the computer for a while with the case cover off and physically
>> check the fan operation if the message reoccurs.
>> Replace the fan. Unless it is a unique fan, it is only a few dollars,
>> fairly easy to replace and gives peace of mind.
>>
>> Tom
>>
>>
>>
>> Donald DeWitt wrote:
>>
>>     
>>> Hello everyone,
>>>
>>> I have a 4.5 year old Dell Dimension 8400 running XP. When I turned on the
>>> computer this morning there was a message at the top of a black screen:
>>> CPU
>>> fan failure. Press f1 to continue or press f2 for setup. By pressing f1
>>> the
>>> computer continues to boot up normally. Opening up the computer and doing
>>> a
>>> close-up inspection, the fan seems to be working normal, (that is no
>>> unusual
>>> sounds or vibrations). The computer also undergoes a thorough cleaning
>>> inside and out two times a year and it is located in an air-conditioned
>>> environment.
>>>
>>> Question: what should I be doing now to confirm that in fact there is a
>>> fan
>>> problem?
>>>
>>> Don DeWitt
>>>
>>>
>>>
>>>
>>>       
>>     
>

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