Oil heats up faster than water. So, no. You'd have to pump it faster and cool it down more (meaning a higher RPM for the fan, which translates to louder noise). It's a bad idea.
Motorcycles are different. Those fins, coupled with highway speeds, cools them down. But your PC case isn't travelling anywhere, is it? Some high-end air-coolers get the job equally well (if not better) than mainstream watercooling solutions, minus the short-circuit risk. So it may not be worth it if you're not a huge overclock zealot (I know I'm not).
Also, learn2punctuate.