I don't have a 3,27, I have a 4,08 but am in the process of changing over to a 3,46 this year. I have driven my car hard without an oil cooler and whilst it makes me cringe keeping up with the 280s and 3,46s, the car has never overheated. (I got stuck in London in a heatwave last year on Tower Bridge. Heater on full blast - Scary, but never actually over-heated). The cars aren't prone to overheating in my view, but that said people do have problems. I guess that more don't have problems working on the theory that no one comes to this site and makes a post about a drive they did when the car didn't overheat. If you're car's fine, I wouldn't worry at this stage, and if you have a problem, come back and take advice.