B737-500 diverts to an en route airport when left engine oil temperature exceeds limits.

Attributes
ACN	700333
Time
Date	200606
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : zzz.artcc
State Reference	US
Altitude	msl single value : 36000
Environment
Flight Conditions	VMC
Aircraft 1
Controlling Facilities	artcc : zzz.artcc
Operator	common carrier : air carrier
Make Model Name	B737-500
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Experience	flight time last 90 days : 150 flight time total : 5500 flight time type : 2900
ASRS Report	700333
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Experience	flight time last 90 days : 210 flight time total : 4400 flight time type : 1200
ASRS Report	700470
Events
Anomaly	aircraft equipment problem : critical
Resolutory Action	flight crew : diverted to another airport flight crew : declared emergency
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

Noticed that the left engine oil temperature was about 50 degrees higher than the right on climb out; but still within limits. Shortly after reaching cruise we noticed the left engine oil temperature was exceeding limits. We ran the high oil temperature checklist; declared an emergency and diverted to ZZZ. When we pulled the throttle to idle; the oil temperature came back into limits so we left the engine at idle. Uneventful visual approach and landing. No human factors were involved.

Original NASA ASRS Text

Title: B737-500 DIVERTS TO AN ENRTE ARPT WHEN L ENG OIL TEMP EXCEEDS LIMITS.

Narrative: NOTICED THAT THE L ENG OIL TEMP WAS ABOUT 50 DEGS HIGHER THAN THE R ON CLBOUT; BUT STILL WITHIN LIMITS. SHORTLY AFTER REACHING CRUISE WE NOTICED THE L ENG OIL TEMP WAS EXCEEDING LIMITS. WE RAN THE HIGH OIL TEMP CHKLIST; DECLARED AN EMER AND DIVERTED TO ZZZ. WHEN WE PULLED THE THROTTLE TO IDLE; THE OIL TEMP CAME BACK INTO LIMITS SO WE LEFT THE ENG AT IDLE. UNEVENTFUL VISUAL APCH AND LNDG. NO HUMAN FACTORS WERE INVOLVED.

Data retrieved from NASA's ASRS site as of January 2009 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.