Split cooling with custom, self bleeding, BMW tank. Input needed.

This allows the two system to share the same expansion tank.
The intercooler system is filled from the engine cooling system. Once filled and bled there should not be hardly any coolant coming from the engine cooling system into the intercooler system, but they are still connected together.
On some of the other cars, I see that bleed fitting on the return line is routed to the expansion tank. With that system there will always be a very small amount of engine coolant entering the intercooler system as it is replaced from the small amount bled off of that bleed line.
To say there is no way for the engine coolant to enter the intercooler system is not accurate. After all that is how the system is filled in the first place.
The question is how much of a difference splitting the system makes on the E55. I will be there is a difference, but not as much as you might think.
G
http://www.ebay.com/itm/Pressure-Rel...-/161098491498
Then the brake reservoir should behave like an actual coolant reservoir.





