6.7L Diesel Engine Maintenance

6.7l diesel maintenance

Since the launch of the 2011 Super Duty, Ford Motor Company has made an effort to promote awareness of critical Power Stroke® diesel engine operating characteristics and maintenance requirements. It is imperative that 6.7L customers understand that more frequent maintenance is required when their vehicle is utilized under special operating conditions (towing, long idle/commercial delivery, off road/dusty, biodiesel).

  • Engine failures can occur due to lack of proper coolant strength and carboxylates level checks.
  • Turbocharger failures can occur due to a lack of proper lubrication or dusting from unfiltered intake air.
  • Turbocharger & EGR valve collect coking deposits faster in colder weather without proper maintenance.
  • Low fuel pressure and/or fuel volume due to fuel filter contamination can cause hard starting and slower cranking times.
  • Fuel injector internal failures can occur due to loss of fuel pressure from clogged filters, fuel line freeze up, and the injector spool valve can stick when the oil is contaminated and/or the wrong oil viscosity.


Maintenance frequency is also dependent on miles, engine idle hours, normal vs. severe service conditions, quality of materials used – primarily ULSD fuel, engine oil, air and oil filter element, coolant level and quality, etc. 6.7L customers must adhere to the maintenance interval guidelines using the Intelligent Oil Life Monitoring System, vehicle mileage OR engine idle hours, whichever is attained first. Engine idle hours of operation, accessed via the vehicle message center, are particularly important if the vehicle is used for periods of extended engine idling where vehicle mileage is not accrued.

  • Frequent or extended idling
    • Over 10 minutes per hour of idling
    • Frequent low speed operation
    • Sustained heavy traffic less then 25 MPH (40 KMH)
  • One hour of idle time is equal to approximately 25 miles (40 km) of driving
  • Operating in sustained ambient temperatures below -10°F (-23°C) or above 100°F (38°C)
  • Operating in severe dust or off-road conditions
  • Towing a trailer over 1,000 miles (1,600 km)
  • Sustained, high speed driving at Gross Vehicle Weight
  • Rating (maximum loaded weight for vehicle operation)
  • Use of any Biodiesel: B20 is the maximum allowable blend to be used with the 6.7L Power Stroke® Diesel


HOW TO CALCULATE EXTENDED IDLE CONDITIONS (Intelligent Oil Life Monitor does this automatically for you)
Engine Idle Hours vs. Vehicle Mileage Formula (Helpful to determine if “Extended Idle” condition exists)
Record the engine idle hours from the vehicle and multiply the number by 25 (1 hour of engine running time is equal to approximately 25 miles).


  • If the number is less than the miles on the odometer, the vehicle is driven more than it idles – use vehicle mileage to determine maintenance intervals (other than oil change intervals)
  • If the number is greater than the mileage on the odometer, the vehicle idles more than it is driven – use engine hours of operation to determine maintenance intervals


This system uses information from a sensor in the oil pan, the Powertrain Control Module and an algorithm to calculate the proper oil change interval. The interval is calculated based upon the vehicle operating conditions:


  • Engine speed & torque
  • Oil & Coolant temperature
  • Hours of operation and Mileage (Idle Hours and Total Hours)
  • Driving habits
  • Number of Diesel Particulate Filter regens or cleaning cycles


The system uses the Message Center to display when the oil needs to be changed:

  • “ENGINE OIL CHANGE SOON” at 5% oil life remaining
  • “OIL CHANGE REQUIRED” at 0% oil life remaining


The IOLM system applies to fuel filter replacement. At the 3rd oil change interval the IOLM system will notify the driver that the fuel filters must be replaced. Additionally, there is a sensor in the fuel line that informs the driver, via the instrument cluster, that the filter is becoming plugged before the 3rd oil change interval. 

This same Extended Engine Hours vs. vehicle mileage formula also applies to engine coolant when operated in special operating conditions. Check for Nitrite Contamination using Rotunda test strip 328-00001 and then the carboxylates level of the coolant using Antifreeze Coolant ELC Contamination Kit, Rotunda part number 328-00008. Add the VC-12 – Motorcraft® Specialty Orange Engine Coolant Revitalizer or replace the Motorcraft Specialty Orange coolant VC-3-B as necessary.

In addition, 6.7L customers should be aware that non-Ford maintenance products (engine oil and oil, air filters, fuel filters and engine coolant) may not provide an adequate level of protection due to varying levels of aftermarket production standards and processes. Please contact Fuller Ford’s service department for additional information on 6.7L Diesel Engine Maintenance @ (513) 352-5800 x 33 or check us out on the web @ http://www.fullerisford.com/service.aspx.

As always, Fuller Ford offers Lifetime Free Oil Changes on ALL new vehicle purchases – in stock or factory ordered. This includes 6.7L Diesel! Fuller Ford is the Cincinnati Tri-State Region’s truck leader. Whether you are coming from Ohio, Kentucky, or Indiana, we are conveniently located right off of I-75, just west of downtown Cincinnati. Check out our entire inventory at www.fullerisford.com.






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