Welcome Guest. Sign in or Signup

4 Answers

Low oil pressure

Asked by: 11409 views ,
Aircraft Systems

Oil pressure at startup, runup, climb, and cruise was in the green range.  After flying for about 20 minutes, tried some power reductions to descend.  Oil pressures dropped below green once below 1800 rpm and were nearly at the redline when at 1000 rpm.  Oil temperatures had increased as the oil warmed up throughout the flight but remained steady during the pressure drops at the lower rpms.  Increasing power above 1800 rpm brings oil pressure back in green arc.  Mechanic says the oil pressure relief valve needs to be adjusted. What are your opinions on whether the aircraft is safe to fly and whether it show be flown before this adjustment is properly made?

Ace Any FAA Written Test!
Actual FAA Questions / Free Lifetime Updates
The best explanations in the business
Fast, efficient study.
Pass Your Checkride With Confidence!
FAA Practical Test prep that reflects actual checkrides.
Any checkride: Airplane, Helicopter, Glider, etc.
Written and maintained by actual pilot examiners and master CFIs.
The World's Most Trusted eLogbook
Be Organized, Current, Professional, and Safe.
Highly customizable - for student pilots through pros.
Free Transition Service for users of other eLogs.
Our sincere thanks to pilots such as yourself who support AskACFI while helping themselves by using the awesome PC, Mac, iPhone/iPad, and Android aviation apps of our sponsors.

4 Answers



  1. Steve Butler on Jul 19, 2013

    One of the items required for day VFR flight is an operable oil pressure gauge. It would appear that either the gauge is inoperative or it is giving accurate readings and the engine is not getting proper lubrication under some circumstances. While I might not be too concerned about flying it across town to reposition it for repair, I think it is time to ground it.

    +2 Votes Thumb up 2 Votes Thumb down 0 Votes



  2. Hans Mathews on Jul 20, 2013

    I agree with Steve, I would ground the plane until I had this resolved. This could be especially bad if your craft has a CS prop. Loose the oil and you loose prop control. Single engine will fail to low pitch, but a twin could fail feathered, so this is an important item, more so than just bearing lube.

    As to the mechanics speculation, it seems plausible. Relief valves don’t usually “un adjust” themselves, but they do get bits of debris that keep them from reacting and sealing properly.

    You didn’t say where your flying, but I would also consider if your oil is correct for your environment, there are usually choices based on local ambients in the POH. If you have a thin oil meant for a cool climate and are running around down here in the south you could have the symptoms you are reporting.

    Hans

    0 Votes Thumb up 0 Votes Thumb down 0 Votes



  3. Mr NineThreeKilo on Jul 21, 2013

    CHT temp?

    We have a similar issue on a IO550, on a good pitch down she will ready 0 oil pressure, good oil temp and CHTs, its a CS prop and the prop wont wonder (lack of oil pressure will cause a CS prop to increase in RPM on a single engine), so we know its the sender, gauge or something.

    How much oil did you have in the plane pre and post flight

    In our case the plane was fine

    You REALLY want to get to the bottom if this issue (or perhaps non-issue) before you fly much more, if you really do have a oil pressure issue, no oil pressure = no engine in rather short order

    0 Votes Thumb up 0 Votes Thumb down 0 Votes



  4. Jh on Oct 05, 2013

    Excessive oil pressure may indicate a blocked filter, blocked oil gallery or the wrong grade of oil. Low oil pressure indicates worn bearings on the crank shaft or a broken oil pump.

    0 Votes Thumb up 0 Votes Thumb down 0 Votes


The following terms have been auto-detected the question above and any answers or discussion provided. Click on a term to see its definition from the Dauntless Aviation JargonBuster Glossary.

Answer Question

Our sincere thanks to all who contribute constructively to this forum in answering flight training questions. If you are a flight instructor or represent a flight school / FBO offering flight instruction, you are welcome to include links to your site and related contact information as it pertains to offering local flight instruction in a specific geographic area. Additionally, direct links to FAA and related official government sources of information are welcome. However we thank you for your understanding that links to other sites or text that may be construed as explicit or implicit advertising of other business, sites, or goods/services are not permitted even if such links nominally are relevant to the question asked.