6.9L & 7.3L IDI Diesel Maintenance Schedule

Service Intervals & Information for 6.9, 7.3 IDI Diesels

For the purpose of service intervals, "severe" driving conditions are defined as any combination of the following:

• Excessive idling (more than 10 minutes of idling per hour of driving)
• Frequent short trips or start-shutdown cycles in which the engine does not reach full operating temperature
• Driving in dusty environments
• Driving off-road or in conditions that require the use of 4 wheel drive
• Frequent towing or hauling

6.9L, 7.3L IDI Service Intervals

Note - Select service intervals represent an adaptation of Ford's OEM recommendations that account for procedures not listed in the original owners manual/diesel supplement.

Replace engine air filter

30,000 miles regardless of condition
Check at oil change intervals, replace as necessary

Replace engine oil & oil filter

5,000 miles or 6 months under normal driving conditions
2,500 miles or 3 months under severe driving conditions

Drain fuel water separator

5,000 miles
6.9L IDI water separator located on driver side firewall
7.3L IDI water separator integrated into fuel filter assembly

Replace fuel filter

15,000 miles under normal driving conditions
7,500 miles under severe driving conditions

Check & adjust drive belt tension

15,000 miles (models with non-serpentine belt only, i.e. no belt tensioner)

Inspect crankcase depression
regulator valve (CDR)

30,000 miles
Suggest replacing every 60,000 miles regardless of condition

Check coolant condition

Annually test for proper SCA/DCA level under normal conditions
More frequent inspection is advised under severe driving conditions

Flush & replace engine coolant

36 months regardless of mileage

Replace automatic transmission
fluid & filter

30,000 miles

Replace manual transmission fluid

60,000 miles

Replace transfer case fluid

60,000 miles (more frequent service advised if 4 wheel drive used frequently)
Replace immediately anytime transfer case is submerged

Replace front differential fluid (4x4)

100,000 miles under normal driving conditions
30,000 miles under severe driving conditions
Replace immediately anytime differential is submerged

Replace rear differential fluid

100,000 miles under normal driving conditions
30,000 miles under severe driving conditions
Replace immediately anytime differential is submerged

6.9L, 7.3L IDI Service Part Numbers

Note - All part numbers listed applicable to Ford F-Series trucks (F-250/F-350/F-Super Duty). Select part numbers may not be compatible with engines found in E-Series/Econoline vans; always verify compatibility with your parts specialist.

Engine air filter

6.9L, 7.3L IDI, NA

Motorcraft FA-1057 (Ford E7TZ-9601-A)

7.3L IDI, factory turbo

Motorcraft FA-1605 (Ford F3TZ-9601-Z)

Engine oil filter

Motorcraft FL-784

Engine oil fill cap

Stant 10066

Fuel filter

6.9L IDI

Motorcraft FD-811

7.3L IDI

Motorcraft FD-3375

Crankcase depression regulator (CDR) valve

Ford E3TZ-6A665-A (listed as "adapter" by Ford)

CDR valve grommet/gasket

Ford E3TZ-6A892-A

Fuel Lift pump (low pressure)

Carter M60278 (mechanical lift pump, engine block mounted)

Glow plug

6.9L IDI

Motorcraft ZD1A (Ford E5TZ-12A342-B)

7.3L IDI

Motorcraft ZD9 (Ford F2TZ-12A342-A)

Glow plug controller

6.9L IDI

Motorcraft SW5241

7.3L IDI

Ford E7TZ-12B533-A

Glow plug relay

Motorcraft DY-861 (7.3L IDI only)


Motorcraft RT-1049 (Ford E5TZ-8575-C)

Thermostat housing gasket

Motorcraft RG-531 (Ford E3TZ-8255-A)

Radiator cap

Stant 10229


Motorcraft VC-8 or Fleetguard DCA4 DCA60L recommended
Use with test strips Fleetguard CC2602A

Engine oil cooler assembly

Ford F3TZ-6A642-C

Engine oil cooler o-rings [1]

Large o-ring

Ford 1C3Z-6C610-BA

Small o-ring

Ford 1C3Z-6K649-BA

Engine oil cooler header gaskets

Ford F7TZ-6A636-AAA (front) & F4TZ-6A636-A (rear) +oil cooler assembly to engine block, front and rear gaskets

Automatic transmission filter

C6, 3 spd

Motorcraft FT-52 (Ford D5AZ-7A098-B)

AOD, 4 spd

Motorcraft FT-58 (Ford E1AZ-7A098-A)

2WD E4OD, 4 spd

Motorcraft FT-113 (Ford YC3P-7G186-AB)

4WD E4OD, 4 spd

Motorcraft FT-114 (Ford YC3Z-7A098-AA)

[1] 1983/1984 model year 6.9L diesels may have a 6 o-ring oil cooler which requires (4) small and (2) large oil cooler o-rings. Later 6.9L diesels and all 7.3L IDI diesels require (2) small and (2) large o-rings.

6.9L, 7.3L IDI Fluid Specs & Capacities

Note - All fluid capacities are nominal (approximate) and should be used as a reference for acquiring fluids only. Always fill to dipstick or fill plug level as applicable. Automatic transmission fluid capacity is typically total dry fill. A supplemental additive/friction modifier may be required in limited slip differentials, use Motorcraft XL-3 limited slip differential additive.

Engine oil

10 quarts with filter

Engine oil viscosity

SAE 15W-40 recommended in ambient temperatures greater than 0° F
(preferred all-purpose oil viscosity within temperature range)

SAE 10W-30 appropriate in ambient temperatures less than 60° F
(preferred oil viscosity in cold weather)

SAE 30 appropriate in ambient temperatures greater than 30° F
(not typically recommended but compatible)

Cooling system

29 - 31 quarts (7.25 - 7.75 gallons), may vary by application

Motorcraft VC-5

Automatic transmission fluid

C6, 3 spd

12 - 13.5 quarts

MERCON V ATF (supersedes original spec)

AOD, 4 spd

12.25 quarts

MERCON V ATF (supersedes original spec)

E4OD, 4 spd

13.5 quarts

MERCON V ATF (supersedes original spec)

Manual transmission fluid

T-19, 4 spd

3.5 quarts

50W engine oil or 80W-90 non-hypoid gear oil

ZF S5-42, 5 spd

3.38 quarts


Transfer case

BorgWarner BW1345

3.25 quarts

Motorcraft XL-12 transfer case fluid

BorgWarner BW1356

2 quarts

Motorcraft XL-12 transfer case fluid

Front differential

Dana 50 (TTB IFS)

2 quarts

SAE 80W-90 gear oil

Dana 60
(F-350, F-Super Duty only)

3.0 quarts

SAE 80W-90 gear oil

Rear differential

Sterling 10.25

3.25 - 3.50 quarts

SAE 75W-140 gear oil, full synthetic recommended

Dana 60

3 quarts

SAE 80W-90 gear oil

Dana 70

3.25 - 3.7 quarts

80W-90 gear oil

Dana 80

4.2 quarts

SAE 75W-140 full synthetic