I have read plenty on Mocal products, and have been using them for years. Oil like all fluids will take the path of least resistance. If you prick your garden hose with a push pin and then turn it on, you won't see much of any flow out of it. 99% will be coming out the large open end. This is going to be the same effect. I really doubt the small amount of oil going through the cooler is going to make a noticeable effect. Even with an overly large cooler.

If you are really concerned with this then i would suggest using the factory "coolant collar" that is used on some of the colder climate G37s. That would allow the coolant to help bring the oil up to temp quicker, as well as maintain more consistent temps.

Or... you could just cover a portion of the cooler...

Have you ever felt the cooler after an install and firing it up from cold? A significant amount of circulation is readily evident almost immediately. I just did my 4th cooler install with these same parts just a week ago. The cooler will get fairly hot, well before the oil hits 180 degrees indicating more than a Pinholes worth of volume flowing through it. No one knows what percentage of bleed is occurring but Real world experience (on this car) has shown me that Desired temps cannot be reached very quickly, if ever, when it is cold out, using a commonly sized street cooler available in most kits. As Steve mentions above, a simple cover brings the cooler into the correct range when temps are cold out...
A simple U shaped piece of sheet metal works fine and the amount of blockage can be adjusted for your particular winter climate. Approx 1/3 blockage works for me in a North Carolina winter. More will be needed if you're up north:

http://images53.fotki.com/v421/photo...MG_2211-vi.jpg

Paint it black and it's all but invisible on the car. Takes but minutes to install or remove.

http://images53.fotki.com/v420/photo...MG_2217-vi.jpg

thats what she said

But she was wrong....:tup:

Like always, but we humor her and tell her shes right anyway;)