Overhaul Process

Overhaul Process

Our Twenty-Five Step Overhaul Process

Our Process for Overhaul and F.A.A. Re-Certification includes these 25 steps:

1. Upon receipt, each oil cooler (or fuel heater, valve assembly, heat exchanger, condenser, or evaporator, herein after referred to as “unit”) is checked for serial numbers and part numbers against customer purchase order or core / purchase documents.

2. Pacific Oil Cooler Service, Inc. work order number and green tag are assigned and attached to each unit.

3. Unit is pre-inspected by a certified technician for overall condition, reparability, A.D. status, and correct part number identification.

4. Unit is drained and disassembled.

5. Unit is cleaned in a vapor-degreaser, both inside and outside.

6. Outside areas are cleaned with compressed air to remove any contamination.

7. Appropriate hoses are attached to mate each unit with our flushing benches.

8. First pressure check is performed.

9. Unit is inspected for cracks and signs of leakage.

10. Unit is repaired, if repairable.

11. Ultra-sonic cleaning of all internal and external surfaces is performed as the first step of a four-step decontamination process -a Pacific Oil Cooler Service exclusive.

12. Unit is flushed in both directions to X-Ray quality (decontamination step #2).

13. High pressure and high volume flushing is performed (decontamination step #3) until a 100 micron particle-size threshold is achieved.

14. Each unit is then flushed with Stoddard solvent under high pressure and high volume, in both directions to X-Ray quality (until a 10-micron exhaust screen shows no contamination) – decontamination step #4.

15. Unit is drained and blown dry.

16. Any needed fin straightening is performed.

17. Vernatherm is thermally tested for proper operation (if unit is so equipped), and replaced if necessary.

18. Seals and O-rings are replaced, if so equipped.

19. Unit is re-assembled and safety-wired as necessary.

20. Unit is again pressure-tested and inspected for any sign of leakage.

If leaks are detected, they are repaired (if repairable). After repairs are successfully performed, unit is then re-flushed and resumes the overhaul process back at step #12.

21. Unit is bead blasted and Iridite treated, then pressure tested for a third time.

22. All openings are sealed, protective plugs are applied as needed.

Painting of oil coolers that require paint – or the application of Mil-spec epoxy primer – is performed at this time.

23. Unit is given Final Inspection.

24. F.A.A. Form 8130-3 is completed and attached to the completed part.

25. Unit is individually packaged to prevent contamination in preparation for customer delivery.


Cleaning procedures will be integrated with your Repair Spec. MJ-70-24-13-06-ES, and/or maintenance manuals from manufacturer, as necessary.
Station Procedure Manual is available for your inspection upon request at our facility.
All shop equipment and work complies with rigid F.A.A. and military specifications.
Painting, when required or requested by customer, is performed using appropriate Mil. Spec. primers and paints which are expertly applied under controlled conditions. Pacific Oil Cooler Service, Inc. offers this service at no additional overhaul cost.
Call to get a quote: (800) 866-7335

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