Same problem. Macbook air mid-2013 13” w/ os x el capitan. Suddenly the fan began to work crazy with silly kernel usage. Tried some of the tips described above without success.
My battery has 1200 cycles, may that be the reason? Anybody succeded after battery replacement?
Downloaded macs fan control, thats a great app, at least i dont hear any noise anymore w the manual specs. I set the rpm around 2000 is that ok? All sensors show degrees between 30-50 celcius.
I want also try the delete plits file trick. Would that be wise? Anyone w permanent succes?