I'm installing an oil cooler and I was a little surprised that 1/2" ID tube is enough to carry the oil without restriction.. or is it? any thoughts out there? dosent 5/8 sound better? On my cooler, the ports have what I think are 1/2" quick disconnects, but it looks like the tubing itself may be bigger but cant be sure unless I cut the "bump" off the end of the nip (theres still plenty of pipe left) but I'm wondering if anyone out there has a cooler and what size line do you use. Thanks a lot, I appreciate the input.