Some people may call it an intercooler, but if you are not sure what I'm talking about, it's the air radiator in front of your water radiator. The one that cools the air from your turbo before it enters the engine. It's true to say that charge air coolers are getting better. Five years ago, close to 40 per cent of new truck CAC's were leaking, it is down to around the 25 per cent mark now. However, that's still one in four coolers leaking from new.