Not sure this really helps anyone, but while rebuilding my V12 I found something interesting. The donut oil cooler is held on with a bolt that is hollow (https://www.scuderiacarparts.com/par...-clr-bolt.html). Oil comes from a side passage at the bottom of the bolt, makes a 90 degree turn and goes up into the filter (NB, it may go the other direction, but either way, the oil is flowing).

Turns out that the connector bolt is 3/16" too long and partially blocks the oil flow. It works out to about a 15% reduction in area. I'm going to fix mine by chucking it in a lathe and parting off some of the bolt. I wonder if this has much to do with the poor performance of the oil system in the car?

Given the long cam shafts and high pressure pump, I'm adding an aftermarket pressure gauge and oil temperature gauge by using the spare oil galley plug (Port 27 on this sheet:https://www.scuderiacarparts.com/par.../151/668/23902)

This seems like a nice setup, and easy to add since everything is out of the way: https://www.glowshiftdirect.com/10-c...ressure-gauge/

 

What year is your V12?

 

It's a 2006, but the connector bolt and donut cooler (and block) are the same for all models of DB9 and Rapide.