I've been running a thermaltake mobile 2 fan on the left side of my 622 for probably 2 years now and I have not had any trouble from my 622 in all that time. I have it running slow enough to be nearly silent but it still pulls heat out of the unit. My current temps are:
High: 127
Low: 107
AVG: 116
High: 127
Low: 107
AVG: 116