Oil Pressure, Can It Be Too High?

[Richie-Van-GTi 71 2 Cars]

Im currently reading 100psi oil pressure at 1400 rpm on a warm engine, guage actually tops out at 100 so it may be more, will this be too high or do you think it will be ok? Not blowing any into the catch tank yet though.

[C_W 3 1 Cars]

Wouldnt be unusual on a stone cold engine but when hot it does sound high. Not sure what'd be causing it though as even if the relief valve was stuck closed I doubt when hot it would normally need to open.

[jim21070 2]

Yes it can be too high.

 

Firstly, very high oil pressure can sap power as so much is wasted in running the oil pump. The more pressure, the more power is consumed by the pump. High pressure does not necessarily mean the engine is better protected either.

 

Secondly, very high oil pressure can indicate a blockage in the pressure relief valve assembly or a blockage or restriction in an oil gallery running to something critical like a main bearing.

 

If you're reading this on a standard Pug electric gauge it is more than likely the sender or gauge telling porkies. If it is on a good quality mechanical gauge, I'd be stripping the engine to find out why.

[Richie-Van-GTi 71 2 Cars]

Im reading this on an autometer electronic guage with the correct autometer sender (brand new sender). Every bit of pipe is new externally so theres no blockages there, the main breather is onto a catch tank which is vented with a brand new filter, the head was recently worked on by a machine shop and was throughly cleaned afterwards to ensure no metal shavings etc were present so I doubt theres any issues here, filter and oil is nice and fresh and the sump pan was only removed 2 days ago and cleaned out inside, oil pump was inspected at the same time and the guaze is intact ad no debris clogging it so I cant foresee anything getting through to the pressure relief spring although stranger things have happened. The block was taken apart not so long back as well when fitting the new crank, at which point I flushed the oil ways out also so they should be fine. I'll run it a bit more and see if it drops down at all as it gets hotter. Max temp the engine has seen at the moment is around 85 degrees and has only run for short 5 minute bursts due to me choking on fumes in the garage

[Anthony 1,003]

If you've only run it for 5 minutes the oil temperature will still be cold, and give high oil pressure. Certainly I've had 205's before now that, if you believe the slightly questionable standard oil pressure gauge, have been running 100psi+ pressure when cold before now, but it's always dropped down to around 75psi @ 4000rpm or so when the oil is upto temperature.

 

Drive it for 10-15 minutes on the road (leaving it to idle in the garage is no good really) and you should find that the pressure will come down.

[Richie-Van-GTi 71 2 Cars]

driving it isnt an option right now, no drivers door, no windows, no bonnet and a very very rough base map, plus the discs are rusted up to buggery. I just had it running for about 15 mins, fans had cut in twice (87 degree switch in rad) temp reading was around 89 degrees at highest point and the oil pressure dropped to about 97 psi. I was gearing myself up to the oil pump relie check wehn I noticed something about the bottle of oil. I didnt buy it, grabbed it off my mate when mine bore washed, had asked for 10/40. he must of grabbed the wrong bottle and I stupidly didnt check it. Its running on 15/40 mineral oil , I will try and get 5 litres of 10/40 semi today instead

[C_W 3 1 Cars]

I don't think that will make much difference? (the oil change)

[Richie-Van-GTi 71 2 Cars]

I dont either bits its worth checking first before stripping the sump and pump again.

[tom_m 0]

is this the engine in your sig? XU10 book figures for oil pressure is 6 bar at 3k+ so it sounds to me like your spot on there to me

[gti_al 1]

I doubt that the viscosity change will achieve anything either - my pressure was the same using watery running in stuff as the elf semi 15/40 in it now. Where is the oil temp getting to now anyway? With mine the oil pressure doesn't drop until the water has been at operating temperatures for 5 - 10 mins...

 

Off topic slightly - should i be worried by hot idling pressure? It is often on the lowest white mark, before climbing to point straight up at 3000+ rpm. Does that sound odd? When cold it is one mark from full...

 

Good luck with everything though richie - i am very interested to see what you get from the xu10j4r.

[Anthony 1,003]

Off topic slightly - should i be worried by hot idling pressure? It is often on the lowest white mark, before climbing to point straight up at 3000+ rpm. Does that sound odd? When cold it is one mark from full...

That sounds pretty normal to me - so long as the low pressure light isn't on at hot idle I really wouldn't worry too much

[Richie-Van-GTi 71 2 Cars]

little update, I was naughty and took the car around the block (yes with no door etc), then had it sat outside the garage varying the engine speed etc looking at AFRs etc for a good half hour. During which time the oil pressure dropped down to around 75psi at 1400 rpm. So this means it coming more into the normal range when hot and lets me relax a bit