is there any steps to take to make sure the turbo intercooler is doing what it,s meant to do.  also same ? re oilcooler. my traktor is lumpy when warm, but runs ok.

I wd40 the intercooler fan to get it going then wired it to the air-con fan it runs slow but when it gets hot it speeds up ok
my tractor runs like a old dmu sometimes at idle  other times its smooth.
ive noticed its more so in cooler weather