Fulltext TSBs

Technical Service Bulletins

TSB
11-1-7
  • 6.4L DIESEL ENGINES – RADIATOR LEAK DUE TO HYPER-EXTENDED BYPASS THERMOSTAT
Publication Date: January 19, 2011

FORD:
2008-2010 F-250, F-350, F-450, F-550

This article supersedes TSB 10-17-9 to update the Service Procedure.

ISSUE:

Some 2008-2010 F-Super Duty vehicles equipped with a 6.4L diesel engine may experience an external coolant leak at the radiator. This may be caused by a hyper-extended thermostat. If the bypass thermostat hyper-extends, it causes the primary thermostat to oscillate. This oscillation causes thermal spikes throughout the cooling system and stress on the radiator tubes.

ACTION:

Follow the Service Procedure steps to correct the condition.

SERVICE PROCEDURE

  1. Remove the radiator and thermostat. Refer to Workshop Manual (WSM), Section 303-03.
  2. Inspect the bypass thermostat for being hyper-extended.

    NOTE:THERMOSTAT RUBBER SEAL DAMAGE IS NOT RELATED TO RADIATOR FAILURE. A MISSING OR DAMAGED RUBBER SEAL MAY IMPACT COLD WEATHER CAB WARM-UP ONLY AND SHOULD BE REPAIRED BY REPLACING THE THERMOSTAT.

    1. Greater than 45 mm (1.77″) – Hyper-extended. (Figure1)


      Figure 1 – Article 11-1-7




      Figure 2 – Article 11-1-7

    2. Less than 45 mm (1.77″) – Normal. (Figure 2)
  3. Is the bypass thermostat hyper-extended?
    1. Yes – Replace the thermostat and radiator. Refer to WSM, section 303-03 Cooling System for both radiator and thermostat replacement and approved system filling and bleeding procedures. Hyper-extension is the only thermostat failure mode that causes radiator damage.

      NOTE:WARRANTABLE REPAIR FOR THE THERMOSTAT UP TO 5 YEARS OR 100,000 MILES. HYPER-EXTENSION OF THE THERMOSTAT WILL PROVIDE RELATED DAMAGE COVERAGE FOR RADIATOR BEYOND THE EXISTING 3 YEARS AND 36,000 MILES RADIATOR COVERAGE.

    2. No – The thermostat is not hyper-extended and did not cause the radiator leak. Do not use this procedure to provide coverage for the radiator leak beyond 3 years or 36,000 miles. Reinstall the thermostat. Refer to WSM section 303-03 Cooling System for radiator and thermostat replacement and approved system filling and bleeding procedures.

PART NUMBERPART NAME
8C3Z-8575-DThermostat Assembly
8C3Z-8009-BRadiator Assembly

WARRANTY STATUS:

Eligible Under Provisions Of New Vehicle Limited Warranty Coverage
IMPORTANT: Warranty coverage limits/policies are not altered by a TSB. Warranty coverage limits are determined by the identified causal part.

OPERATIONDESCRIPTIONTIME
110107A2008-2010 F-Super Duty Remove Radiator and Thermostats, Inspect Thermostats For Hyper-Extension, Defective, Replace Both Radiator and Thermostats (Do Not Use With Any Other Labor Operation)3.2 Hrs.

DEALER CODING

BASIC PART NO.CONDITION CODE
857542

NOTE: The information in Technical Service Bulletins is intended for use by trained, professional technicians with the knowledge, tools, and equipment to do the job properly and safely. It informs these technicians of conditions that may occur on some vehicles, or provides information that could assist in proper vehicle service. The procedures should not be performed by “do-it-yourselfers”. Do not assume that a condition described affects your car or truck. Contact a Ford, Lincoln, or Mercury dealership to determine whether the Bulletin applies to your vehicle. Warranty Policy and Extended Service Plan documentation determine Warranty and/or Extended Service Plan coverage unless stated otherwise in the TSB article. The information in this Technical Service Bulletin (TSB) was current at the time of printing. Ford Motor Company reserves the right to supercede this information with updates. The most recent information is available through Ford Motor Company's on-line technical resources.

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