sorry for crosspostings…
Hi everybody 
I’ve obtained XJ6 S3 oil filter head,oil thermostat and oil cooler and fitted it to my S1 XKE. The engine has been rebuilt and I’ve not started it yet.
Now a question arose: which port of the oil filter head is the outlet, which is the inlet?
This is a foto of the same oil filter head (taken from the web, we are looking at the rear):
This is how I’ve fitted the oil cooler:
These are the fitting instructions of the oil thermostat:
If you look at the fitting instructions then they say that the engine-side of the thermostat has specific in- and outlets, which must be connected to the corresponding ports at the oil filter head. Apparently it might be a bad idea to mix up these ports.
Now, the fitting instructions recommend to observe the ports at the oil filter head when cranking the engine. Unfortunately this is not really an option for me, because I have to remove the inlet manifold from the engine in order to properly attach the oilpipes to the oil filter head.
What could be the inlet and the outlet ports of the oil filter head?
I have a slight idea, but I am not really sure:
- The oil pump delivers oil to the chamber at the bottom.
- The oil enters the oil cooler outlet in the bottom chamber, so this would be the outlet of the filter head.
- From the oil cooler the oil flows back through the inlet into the top chamber.
- From the top chamber, the oil flows through the oil filter element to the center chamber, which goes to the oil gallery in the engine block, right?
- There is a valve which lets oil from the bottom chamber to the top chamber, probably if the oil cooler lines are blocked?
So my conclusion is:
- outlet is the port at the right hand side (which is the rear side if fitted to the engine)
- inlet is at the left hand side (front if fitted).
Leaving discussions aside whether pros and cons of oil-coolers (yes, I do race… a bit 
), what is your educated guess with regard to the ports?
Thanks for you help
greetings
Dan
