MACK U 1974: ENGINE AND ENGINE COOLING:COOLING SYSTEM:FAN

General Information

NHTSA Campaign ID Number: 77V173000

Make Model Year
MACK U 1974
Date Owners Notified Date Received by ODI Date Added to Database
1978-03-23 1977-10-12 1979-10-12

Production Dates: 1974-10-01 - 1976-03-01

Manufacturers Involved: Mack Trucks, Inc.

Component: ENGINE AND ENGINE COOLING:COOLING SYSTEM:FAN

Potential Number Of Units Affected: 48000

Report Initiator: ODI ODI Report

Summary

THE FLEX BLADE FANS ON THE INVOLVED VEHICLES MAY DEVELOP CRACKS IN THE LAMINATED STIFFENER AS A RESULT OF FATIGUE DURING OPERATION. IF SUCH A CONDITION EXISTS AND THE CRACKS GO UNDETECTED, CONTINUED OPERATION COULD CAUSE PIECES OF THE STIFFENER TO BREAK OFF.

Remedy

DEALER WILL REPLACE THE ORIGINAL FAN WITH A STEEL FIXED BLADE FAN, FREE OF CHARGE.

Notes

VEHICLE DESCRIPTION: TRUCKS EQUIPPED WITH SIX-CYLINDER ENGINES.SYSTEM: ENGINE COOLING; FAN.CONSEQUENCES OF DEFECT: BROKEN PIECES CAN BE PROPELLED OUTSIDE OF THE FANSHROUD AND WILL PRESENT AN IMMEDIATE DANGER AND POSSIBLE INJURY TO PERSONSSTANDING NEARBY.NOTE: PRIOR TO CORRECTION, VEHICLE SHOULD NOT BE SERVICED WITH THE HOOD RAISEDAND THE ENGINE RUNNING.