AS to the oil pressure levels, I have not noticed any difference, but then I did not document levels prior to the procedures.
As to the location of the oil filter checkvalve vs. the oil pump relief valve, when I return to my office, I will scan in the diagrams for both and e-mail them to you.
I am still confused about the part that the dealer supplied and why it would not fit my car. I will post a detailed question with the appropriate part numbers etc. when I get a chance.
If you have access to the CD's, try the following:
Oil Filter Check Valve Replacement is Procedure 18-1120
RA18.1323-1100 pages 1-6
and my engine no. 119.974.12 required part no. 119.184.01.30
and we also replaced a rubber seal part no. 116.187.00.55
which is inside the adjacent hex headed screw/cap.
Oil Pump Relief Valve
(as this part is 27mm dia. & the hole is only 24 mm
diameter...it does not fit my pump number 119.186.02.01
(unless there is a rear (passenger side access pointl??)
(I understand that my oil pump part no. that I looked at is
likely a casting or subassembly part number and that the
the listed part no. for 92-94 oil pumps is 119.180.09.01)
The dealer gave me a diagram which shows more detail than the CD's and the above cited procedures will identify.
I will note my oil pressures, hot and cold & at various RPM's and let you know.
Hope this helps.