A C172 declared an emergency and diverted due to high engine oil temperature.

Attributes
ACN	484977
Time
Date	200009
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : riv.airport
State Reference	CA
Altitude	msl bound lower : 0 msl bound upper : 4500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : sct.tracon
Operator	general aviation : personal
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Navigation In Use	other
Flight Phase	cruise : level
Flight Plan	VFR
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time last 90 days : 15 flight time total : 78 flight time type : 78
ASRS Report	484977
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : 1
Resolutory Action	controller : issued new clearance flight crew : declared emergency flight crew : diverted to another airport
Consequence	Other
Supplementary
Problem Areas	Maintenance Human Performance Flight Crew Human Performance Company Aircraft
Primary Problem	Flight Crew Human Performance

Narrative:

On sep/xa/00, I was making a cross country flight in a rental aircraft (ful to bng). When I was over march AFB, I realized that the oil temperature gauge was way above redline. After briefly troubleshooting, I declared an emergency and was cleared to land at march AFB. My decisions were good up to this point. From march, I called the mechanic at the FBO. We discussed the problem, and he indicated that it was a faulty gauge. He asked me to fly the plane back if I was comfortable. In my haste to get off the base and to a party, I agreed. In retrospect, I realized that a plane with a faulty oil temperature gauge is not airworthy.

Original NASA ASRS Text

Title: A C172 DECLARED AN EMER AND DIVERTED DUE TO HIGH ENG OIL TEMP.

Narrative: ON SEP/XA/00, I WAS MAKING A XCOUNTRY FLT IN A RENTAL ACFT (FUL TO BNG). WHEN I WAS OVER MARCH AFB, I REALIZED THAT THE OIL TEMP GAUGE WAS WAY ABOVE REDLINE. AFTER BRIEFLY TROUBLESHOOTING, I DECLARED AN EMER AND WAS CLRED TO LAND AT MARCH AFB. MY DECISIONS WERE GOOD UP TO THIS POINT. FROM MARCH, I CALLED THE MECH AT THE FBO. WE DISCUSSED THE PROB, AND HE INDICATED THAT IT WAS A FAULTY GAUGE. HE ASKED ME TO FLY THE PLANE BACK IF I WAS COMFORTABLE. IN MY HASTE TO GET OFF THE BASE AND TO A PARTY, I AGREED. IN RETROSPECT, I REALIZED THAT A PLANE WITH A FAULTY OIL TEMP GAUGE IS NOT AIRWORTHY.

Data retrieved from NASA's ASRS site as of July 2007 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.