Get a better cooler. Sleeve bearing stuff doesn't last.
There's a REASON the only HD 7750 card I have left from my Litecoin GPU mining days that has it's original fan is a Sapphire (though it is the OLDEST of the whole collection) - all of the others had sleeve bearing fans that DIED in the first year or less, the Sapphire has a ball bearing fan and 3+ years after I bought it it's STILL running.
To be fair, all but one of the other CARDS are still running - with a motly assortment of left-over 60mm ball bearing fans left over from outdated CPU coolers from machines I've retired twist-tied to the heatsinks....