MBA A1465 fans revving runs like there is treacle inside

[mobyaki]

A friend gave me an Macbook Air

A1465 fans revving and runs like there is treacle inside...

Even opening a document file is painfully slow.

Friend assures me there was no water damage...logic board looks undamaged...what could the problem be?

 

[BadAsAl]

Did you pull the fan out and make sure it is clean? Does it move freely when you spin it?
Have you PRAM and SMC reset the MacBook?

Not calling anyone a liar, but if I had a penny for every person who swore there was no liquid damage... even a tiny bit can mess up a MacBook...