Pilot reported that oil pressure dropped to 40 psi and oil temp rose 33 degrees; causing a diversion...

Attributes
ACN	1679406
Time
Date	201908
Place
Locale Reference	LOT.Airport
State Reference	IL
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Cardinal 177/177RG
Operating Under FAR Part	Part 91
Flight Phase	Descent
Flight Plan	None
Person 1
Function	Pilot Flying
Qualification	Flight Crew Commercial Flight Crew Instrument
Experience	Flight Crew Last 90 Days 24 Flight Crew Total 2359 Flight Crew Type 1980
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Deviation - Track / Heading All Types

Narrative:

Cruise altitude 8000 ft. From ZZZ to ZZZ1. Given crossing clearance of 4000 ft. 20 NM before ZZZ1. During 16 minute descent oil pressure suddenly dropped from 59 psi to 40 psi and oil temperature rose 33 degrees. I advised ATC and asked for vectors to closest airport ZZZ1 which I rejected in favor of klot for a more favorable runway. During this event I was given additional altitude clearances that I did not comply with because I wanted to conserve a higher altitude in case of catastrophic engine failure. I was in communication and radar contact with ATC during the entire event and am grateful for their assistance.

Original NASA ASRS Text

Title: Pilot reported that oil pressure dropped to 40 PSI and oil temp rose 33 degrees; causing a diversion.

Narrative: Cruise altitude 8000 ft. from ZZZ to ZZZ1. Given crossing clearance of 4000 ft. 20 NM before ZZZ1. During 16 minute descent oil pressure suddenly dropped from 59 PSI to 40 PSI and oil temperature rose 33 degrees. I advised ATC and asked for vectors to closest airport ZZZ1 which I rejected in favor of KLOT for a more favorable runway. During this event I was given additional altitude clearances that I did not comply with because I wanted to conserve a higher altitude in case of catastrophic engine failure. I was in communication and radar contact with ATC during the entire event and am grateful for their assistance.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.