Dreaded oil pressure switches

[mmi]

Yes I did that on a cold engine the other day and it aborted for safety reasons. I’ll repeat with a warm engine but the issue goes away when warm

Hmm, that's an interesting observation - perhaps there is a temperature limit built-in the test. Checked my notes and indeed I did the test engine well warmed up.

 

[manfrotto]

Yes did those... This process of elimination is very frustrating and expensive.. changing the pressure switches gets rid of the problem temporarily...so what's happening exactly during that period? Are the switches continually failing?

Maybe DXX is onto something if switches are failing on a regular basis - see post #35

 

[DXX]

Maybe DXX is onto something if switches are failing on a regular basis - see post #35

Spool valves are bad enough with gear oil let alone filthy soot loaded engine oil, they have very tight machined tolerances.