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Freightliner FLD120 / Classic · fluids

Fluids & Fill AmountsHow much oil, coolant, DEF and gear oil this truck takes, and what specification to buy.

Set the year first

Then read the How much column as a refill quantity, not a dry fill. Fill to the dipstick or sight glass and treat the number as a starting point — a drain never gets everything out.

Pick your truck's year and the table hides everything that does not apply to it.

Fill amounts for Freightliner FLD120 / Classic

FluidHow muchWhat to buyYearsSource
Engine oil - Series 60 12.7L (pan + filter)Change it: 25,000-35,000 mi by duty40 qt (38 L)API CI-4+ or CK-4, 15W-402000–2010Verified
Engine oil - Series 60 14L (pan + filter)Change it: 25,000-35,000 mi by duty40 qt (38 L)API CI-4+ or CK-4, 15W-402000–2010Verified
Engine coolant - SLCChange it: SLC 300,000 mi / 2 yr; ELC 600,000 mi / 4 yrNot verified - consult OEM service manualDetroit Power Cool SLC with SCA or ELC2000–2010Verified
Fuel tankChange it: -50-150 galLow-sulfur diesel (pre-2007); ULSD 15 ppm (2007+)2000–2010Verified

Sources: Detroit DDC-SVC-BRO-0002; Freightliner FLD specification; Series 60 Operator's Guide DDC-SVC-MAN-0039

Two ways to wreck an engine in five minutes

Overfilling an oil pan aerates the oil and can damage bearings. Running a cooling system low can crack a liner or a head before the gauge even moves. Fill slowly, then check the dipstick or sight glass twice.