the eng oil is fed thru the turbo to cool it down, it is standard proceedure to add a cooler when turbocharging a car because the extreme heat of the turbo will break down the oil much faster. Do you have any idea as to how long the turbo has been in the car? Also run 1/4 antifreeze and 3/4 water along w/watter wetter, this will give the necc. anticorrosive protection while maximizing cooling effect, antifreeze protects from freezing but hinders heat transfer considerably, It worked wonders for my excessive heat problems as we recently had 90degree, humid weather here in NY and my temp. stayed a perfect 1/2 mark!