Originally Posted by Vlad
Also, for intercoolers, the touch test may not actually show anything.
A hot to the touch intercooler is an intercooler that exchanges a lot of the heat with the air. It gets hot and cools down the air passing through.
A cold to the touch intercooler is more "insulated" to the air passing through, exchanges less heat, remains cooler and leaves the air passing through hotter.
The reason intercoolers get hot is because of the engine bay heat rising through the intercooler. Stop posting misinformation. Touch test is a great way to see how the intercooler is dealing with heatsoak.