[H] Video card fan problems

[Winterlight]

I have two ASUS EAH4870 video cards installed. One I bought last 
December, and one in September. The December one's fan went out at 
the beginning of this month. One day I sat down to my computer, and 
it had turned it self off overnight. Every time I turned it on it 
would work for a while and then shut down.
Eventually, I figured out that the video cards fan wasn't always 
working, and when it went off it would get hot and the motherboard 
would shut  the PC down.
I RMA'd it .

The card came back yesterday, I installed it, things worked fine 
until a few hours ago at which time my PC turned off. Once again the 
fan was off and would not turn on after powering off and on. I called 
Asus and once again I am RMAing it. <sigh> Could it possibly be 
anything else that is causing this? I asked them if they could just 
send me a new fan to install but no.. I have to spend another 10-15 
bucks sending it back to them.

I am beginning to think I should put my own fan on it,  even if it 
would void the warranty, but where would I find something like that? 
They must be highly engineered.

I feel like I am screwed here, and am going to go another two plus 
weeks with out my other monitors just because some guy didn't replace 
the fan the first time.