Does any one know how much oil resides in the cooler when the engine is at rest?

I plan on pulling the radiator this week for a boil and know that the cooler has to come out with the radiator. I am hoping that the oil in the cooler drains back to the pan after sitting, as I really don't want to drain almost new oil.

Thanks.

I would take the screws out of the cooler and sit it to the side without taking the lines loose.

I was looking at the two long carriage bolts holding the cooler to the radiator today. Looks like I might be able to give it a try. I think I'll have to drop the aux fan though as my hands are a tad too big to fit in there. Maybe I'll enlist junior and his smaller hands first before pulling that aux fan again (it's a PITA to get bolted back in!!!).

Got it out
 

I was able to split the radiator from the cooler without having to remove the oil lines. What a relief, I was worried about the possibility of striping the aluminum fittings. The radiator was fitted very tightly to the cooler, and required a great effort to separate, but steady pressure did the trick.

Now where is the block drain on the 4.5? Is it that big allen plug just behind the oil filter housing?

The radiator is now being boiled and pressure checked. Should have it back tomorrow.