Service | Farmington, MO
A Power Stroke will pull a gooseneck all day in July heat, but it asks for a few things a gas truck never does. Keep the diesel side of the checklist straight and the truck stays ready to work.
Most of the diesel Super Duty trucks we see at Sam Scism Ford earn their keep. They haul hay out past Fredericktown, pull campers down to Clearwater Lake and drag equipment trailers up and down US 67 five days a week.
The 6.7L Power Stroke V8 handles that kind of life well. It also comes with a short list of diesel only chores: diesel exhaust fluid, two fuel filters and a water separator, and an exhaust filter that has to clean itself. Skip those and the truck lets you know, usually at a bad time.
Quick answer: A Ford Super Duty with the Power Stroke diesel needs DEF kept filled, the fuel water separator drained at every oil change or at least monthly per Ford, fuel filters replaced on the schedule in your Owner's Manual, and oil changed when the oil life monitor calls for it. Ford counts heavy towing, long idling and dusty roads as special operating conditions, so a Super Duty that works hard all summer should be serviced on the tougher schedule.
Water separator
Drain every oil change or monthly, per Ford
Oil changes
When the oil life monitor calls for it
Tougher schedule
Towing, long idling, dusty gravel roads
In this post
How Should You Handle DEF in a Ford Super Duty?
Diesel exhaust fluid is a mix of urea and purified water. It gets sprayed into the exhaust, where it breaks down nitrogen oxides before they leave the tailpipe. It doesn't touch the engine or the fuel, and it goes in its own tank behind the blue cap.
How fast you use it depends on how hard the truck works. A Super Duty pulling a loaded trailer burns more diesel and more DEF than one cruising empty. The cluster shows the DEF level and warns you as it drops, and the easy habit is to add some every time you fill up on fuel.
Don't let it run dry. On trucks built under the emissions rules of the last several years, an empty DEF tank can put the engine into reduced power. The EPA has been revising how those limits work, but a working truck can't afford to find out on a gravel road with a trailer behind it.
Summer is the season people forget about DEF storage. It lasts longest somewhere around 23 to 77 degrees, sealed and out of direct sun. A jug riding in the bed all July or sitting in a hot machine shed loses shelf life fast. Buy it in amounts you'll use, keep the cap tight and use fluid that meets the ISO 22241 standard, which Motorcraft DEF does.

Why Do Fuel Filters and the Water Separator Matter on a Power Stroke Diesel?
Diesel fuel does more than burn. It lubricates the high pressure fuel pump and the injectors on its way through. Ford's own parts guidance says water or dirt in the fuel can leave those parts under lubricated and lead to pump and injector failure. On a diesel, clean fuel is cheap insurance for the parts that cost the most to replace.
That's why a 2017 or newer 6.7L Super Duty filters fuel twice. One filter sits on the engine. The other lives in the fuel conditioning module under the truck, which also holds the water separator.
How often should the water separator be drained?
Ford recommends draining it at every oil change or at least once a month, and right away if the Water in Fuel warning comes on. Humid Missouri summers and storage tanks at the farm can both put moisture in diesel, so this isn't a step to skip.
How often do the fuel filters get replaced?
Your Owner's Manual has the interval for your truck and model year. Ford ties it to the special operating conditions schedule when you tow a lot, idle for long stretches or run biodiesel blends, so a hard working truck will come due sooner. We use Motorcraft filters, which Ford builds with a water separating outer wrap.
On a diesel, clean fuel is cheap insurance for the parts that cost the most to replace.
How Do Oil Changes and Regeneration Work on a Ford Super Duty Diesel?
Oil service on the 6.7L Power Stroke is set by the truck. The Intelligent Oil Life Monitor watches load, temperature, idle time and miles, then tells you when it's due. Towing and idling pull that date in, so don't be surprised if a summer of hauling brings the message up early.
Use oil that meets the diesel specification in your Owner's Manual. Our technicians use oil that meets that spec with a Motorcraft filter and reset the monitor before the truck leaves.
The exhaust filter is the other piece. It traps soot, and the truck burns that soot off on its own in a process called regeneration. Ford's owner information says it works more efficiently at a steady speed above about 30 mph, so regular highway miles help it finish.
Trucks that spend most of their life idling at a job site or creeping around a farm have a harder time. Ford has published guidance for those trucks, which can see frequent regen attempts that don't complete and a Drive to Clean message. Many newer Super Duty models also let you start a parked regeneration from the cluster when the truck asks for one.
Farmington driver tip
If your truck lives on short runs between the house, the barn and town, give it a steady highway stretch every so often. A run up US 67 toward Festus or out MO 32 toward Ste. Genevieve at a constant speed gives a regeneration time to finish.
Does Towing in a Missouri Summer Count as Severe Duty for a Ford Super Duty?
It does. Ford's special operating conditions list includes extensive towing, long idling, extended low speed driving and dusty or off road use. A Super Duty that pulls a camper on weekends and hauls feed during the week checks most of those boxes, and July heat adds to the load on the cooling system.
Before a long tow in hot weather, have the coolant level and condition checked, along with belts, hoses and the radiator and intercooler fins. Dust off county gravel clogs air filters faster than you'd think, and a restricted filter makes the engine work harder when it's already hot.
Do not wait on these
Water in Fuel warning. Drain the separator right away or bring the truck in. Running water through the fuel system risks the pump and injectors.
Low DEF or DEF system messages. Add fluid or book a visit before the truck limits power.
Exhaust filter or Drive to Clean messages that keep coming back. Repeated messages after highway driving point to a problem the technician needs to scan.
Rising temperature while towing. Ease off, pull over safely if it climbs, and have the cooling system checked before the next trip.
Schedule ServiceSee Service Specials
What Happens When You Bring Your Ford Super Duty to Sam Scism Ford?
Book it and tell us how the truck works
Schedule online, in the Ford app or at 573-430-1693. Let us know if you tow, how often it idles and any messages you've seen.
Ford trained technicians check the diesel systems
Oil and filter when due, the water separator, fuel filters by schedule, DEF level and any stored codes or regeneration history.
Multi point inspection
Brakes, tires, cooling system, belts, hoses and the air filter all get a look, which matters more on a truck that tows.
Plain talk about what's next
You'll leave knowing what was done and what's coming due, so you can plan service around harvest or a long trip.
Service hours are 8:00 AM to 5:00 PM Monday through Friday, with the desk closed from noon to 1:00 PM. The lounge has Wi-Fi and coffee, and the courtesy shuttle can run you home or to work.
Records matter on a diesel. Ford covers the Power Stroke engine for 5 years or 100,000 miles, whichever comes first, and every new Super Duty sold at Sam Scism Ford comes with Warranty Forever, which asks you to keep up the customary maintenance and hold on to the paperwork.

Book it your way
Schedule online, in the Ford app, or by phone at 573-430-1693. Ask how Warranty Forever covers listed engine, transmission and drive axle parts when you keep up the maintenance.
DEF Questions
How often do I need to add DEF to my Super Duty?
It depends on how much fuel you burn, so heavy towing uses it faster. Most owners add some at fuel stops and watch the level on the cluster.
Can I buy DEF anywhere?
Any DEF that meets the ISO 22241 standard will do, and Motorcraft DEF meets it. Check that the container is sealed and not past its date.
Where should I keep spare DEF at home?
Somewhere shaded and fairly cool, sealed, and not in the truck bed through summer. Heat shortens its shelf life.
Fuel and Filters
What does the Water in Fuel light mean?
The water separator has collected enough water that it needs to be drained. Ford says to drain it right away when that warning shows.
How often should the fuel filters be changed on a 6.7L Power Stroke?
Follow the interval in your Owner's Manual for your model year. Towing, long idling and biodiesel use put you on the special operating conditions schedule, which comes due sooner.
Why does Sam Scism Ford use Motorcraft fuel filters?
Ford designs them for the Power Stroke, including a water separating wrap and an air bleed feature. Fuel system parts cost too much to gamble on a filter.
Oil and Regeneration
How often does a Power Stroke diesel need an oil change?
The Intelligent Oil Life Monitor sets it based on how the truck is used. Expect it sooner during a summer of towing or a lot of idle time.
Is it bad to let my diesel idle for a long time?
Ford lists extended idling as a special operating condition. Long idle periods also make it harder for the exhaust filter to finish cleaning itself.
What should I do when an exhaust filter message comes on?
Follow the message, which often means a steady drive at highway speed or a parked regeneration if your truck offers it. If it keeps returning, book a visit.
Towing and Heat
Does towing change my Super Duty maintenance schedule?
Heavy or frequent towing moves you to Ford's special operating conditions schedule for many items. Your Owner's Manual shows which ones.
What should be checked before a long summer tow?
Coolant, belts, hoses, the air filter, tires and brakes on the truck, plus trailer lights and tires. Book it a few days ahead so there's time to fix anything found.
Do gravel roads affect a diesel?
Dusty roads clog the engine air filter faster, and Ford counts dusty driving as a tougher condition. Have the filter checked at each visit.
Service and Coverage
What factory warranty covers the Power Stroke engine?
Ford's Power Stroke Diesel coverage runs 5 years or 100,000 miles, whichever comes first. Your Warranty Guide lists the covered parts.
Does Warranty Forever cover my diesel truck?
Warranty Forever covers listed engine, transmission and drive axle parts on vehicles sold with it at Sam Scism Ford, as long as you follow the customary maintenance and keep records. See the dealer for details.
How do I book diesel service in Farmington?
Use the Schedule Service page, the Ford app or call 573-430-1693. The service center is at 5019 Flat River Road.
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