Hi All,
Have an engine unknown kms.
Has low oil pressure 60 psi when cold 35psi when at working temp.
I guess oil pump?
Should I replace complete pump or just rotor bits, have yet to extract engine/pump and then look see?

Have looked everywhere to find the factory figures and failed. Have to say that they don't sound that low to me [stands to be corrected ]. I am fairly certain the oil pressure switch for the warning light trips at around 10psi.

Paul

Griff,
Thanks for the oil switch info, mine has come on at v.low tick over and when v.v. hot

According to Haynes the pressure in a M28 engine is 78 to 92 psi @ 6000rpm, if that helps.

In which case yours [subarupete] if you only have 35psi when hot and at high revs then it is on the low side. Oil pressure switches do fail on a regular basis. Are you checking the pressure with guages, if so where are you picking up the feed.

P

Pete,
although Citroen suggest replacing the spring on the pressure release valve as a first step, I've found that it's more likely to be scoring or wear in the oil pump.
Check the rotor tips for scuffing, also check end float of the rotor which should not exceed 0.1mm.

If none of the above is the cause, maybe time to start looking for a replacement crankshaft?

Btw, how just how hot is "v.v. hot"?
If you're exceeding the normal oil temperature by a considerable margin, the readings are bound to be lower than the quoted figures...

ken.

Fitted a gauge to get readings after oil light was on at low revs and temp 130 deg C
Will take pump out to examine

Pete,
might it be a better idea to find a way of reducing your peak oil temperature?
I do not know of any reliable reference for maximum permissible oil temperatures in an A series engine, but on a light aircraft site there is the following advice for Lycoming engines...
Maximum permissible oil temperature 115C, but the preferred range is 65C to 93C.

ken.