Mack MP8 — 12.8L Inline-6
Mack MP8 Engine Oil — Spec, Capacity & Change Interval
The Mack MP8 is the 13-litre engine in the Anthem, Granite and Pinnacle. Mack sets its own oil spec on top of API: EOS-4.5 (CK-4 based) and, on 2021 and newer engines, EOS-5.0 (FA-4 based). Two mistakes show up in most MP8 oil guides: the capacity is 44 quarts, not 40, and there is no such spec as "EOS-4.5 FA-4".
Last reviewed: October 2026 · Based on Mack service literature (Body Builder manual, Service at a Glance) and AMSOIL data sheet G3467
A Mack MP8 oil and filter change takes 44 quarts (42 L, 11 US gallons). Every 2010-and-newer MP8 can run oil meeting Mack EOS-4.5 (API CK-4); on 2021 and newer MP8s, Mack recommends EOS-5.0 (API FA-4) and keeps EOS-4.5 as the minimum. Mack's oil change interval runs from 30,000 mi in severe service to 55,000–60,000 mi in normal duty. Red Seal tech pick for the MP8: AMSOIL Max-Duty 15W-40 (DME).
Change
Inline-6
Every MP8
Normal Duty
MP8 Oil Spec by Model Year — EOS-4.5 vs EOS-5.0
Mack splits MP8 oil at the 2021 model year. 2010–2020 MP8s use Mack EOS-4.5, a CK-4-based spec. On 2021 and newer MP8s, Mack recommends EOS-5.0, an FA-4-based spec, and still accepts EOS-4.5 as the minimum. EOS-5.0 oil is for 2021 and newer engines only.
- Mack SpecEOS-4.5
- API CategoryCK-4
- Primary Viscosity15W-40
- Cold Climate5W-40
- EOS-5.0 / FA-4 Allowed?No — EOS-4.5 only
- AMSOIL ProductDME 15W-40 / DEO 5W-40
- Mack RecommendsEOS-5.0 (FA-4)
- Mack MinimumEOS-4.5 (CK-4)
- EOS-4.5 Acceptable?Yes — Mack's minimum
- Why EOS-5.0Fuel economy
- Why EOS-4.5One oil for every MP8
- AMSOIL ProductDME 15W-40
How to tell which MP8 you have: check the model year on the engine data plate or the emissions label. If it's 2021 or newer, either spec works; if it's 2020 or older, stay on EOS-4.5.
⚠ Two things to get right. EOS-5.0 oil is not backward compatible: in a 2020-or-older MP8, its lower viscosity can drop oil pressure and trigger warnings. And "EOS-4.5 FA-4" is not a real spec. EOS-4.5 is CK-4; Mack's FA-4 spec is EOS-5.0.
Mack MP8 Oil Capacity
An MP8 takes 44 quarts (42 L, 11 US gallons) at an oil and filter change, per Mack's Body Builder manual. The MP7 shares the same 44-quart pan; the MP10 takes 55 quarts. Guides that list the MP8 at 40 quarts are short by a full gallon.
| Engine | Quarts | Litres | Gallons | Notes |
|---|---|---|---|---|
| MP8 | 44 qt | 42 L | 11 gal | Oil and filter change |
| MP7 | 44 qt | 42 L | 11 gal | Same pan as the MP8 |
| MP10 | 55 qt | 52 L | 13.75 gal | Larger pan |
⚠ Always verify capacity with your engine's service label and dipstick. Overfilling causes oil foaming, aeration, and seal damage. Underfilling reduces oil pressure margin under high load.
Buy the Right Oil for an MP8 Service
A Mack MP8 oil and filter change takes 44 quarts, which is 11 US gallons. Two AMSOIL Twin Packs plus one gallon jug is exactly one service. For fleets, one 55-gallon drum covers exactly five MP8 services.
- Formulated to meet Mack EOS-4.5
- One service: 2 Twin Packs (DMETP-CA) + 1 gallon jug (DME1G-EA) = 11 gal
- The Red Seal tech pick for every MP8
- Formulated to meet Mack EOS-4.5
- One service: 2 Twin Packs (DEOTP-CA) + 1 gallon jug (DEO1G-EA) = 11 gal
- Cold cranking to −30°C (−22°F)
- One truck under your own authority qualifies
- Lower cost per service than jugs
- One 275-gallon tote covers 25 MP8 services
- Shipped direct to your shop or yard
EOS-4.5 is Mack's spec for 2010–2020 MP8s and the minimum for 2021+. Run Mack's interval for your duty cycle (up to 55,000 mi in normal duty on EOS-4.5 oils other than Mack's own), and go past it only on oil analysis. Get an Oil Analysis Kit →
MP8 Oil Change Interval
Mack sets the MP8 oil and filter interval by duty, on EOS-4.5 oil, for 2011 and newer engines with the 44-quart pan: 55,000 mi in normal duty (over 6 mpg), 40,000 mi in heavy duty (over 5 mpg) and 30,000 mi in severe duty (under 5 mpg). Mack-branded oil adds 5,000 mi to each. If idle time is over 30%, use the next shorter interval.
| Duty | Fuel Economy | EOS-4.5 Oil (incl. AMSOIL) | Mack-Branded Oil |
|---|---|---|---|
| Normal | Over 6 mpg | 55,000 mi (89,000 km) | 60,000 mi (97,000 km) |
| Heavy | Over 5 mpg | 40,000 mi (64,000 km) | 45,000 mi (72,000 km) |
| Severe | Under 5 mpg | 30,000 mi (48,000 km) | 35,000 mi (56,000 km) |
⚠ Going past Mack's interval? Do it on oil analysis. Mack's own MP8 interval already reaches 55,000 mi in normal duty. A good synthetic gives you more margin inside that interval. Going beyond it safely takes a lab report on your own truck, because idle time, biodiesel blends, EGR cooler leaks and soot loading all shorten oil life.
EOS-4.5 vs EOS-5.0 on the MP8
EOS-4.5 is Mack's CK-4-based spec and works in every 2010-and-newer MP8. EOS-5.0 is Mack's FA-4-based spec for 2021 and newer MP8s, where Mack recommends it for fuel economy. If your fleet has both older and newer Macks, EOS-4.5 is the one oil that covers all of them.
EOS-4.5 — CK-4
- ✓ Every 2010-and-newer MP8
- ✓ Mack's minimum on 2021+ engines
- ✓ Higher HTHS viscosity, more film strength
- ✓ One oil across MP7, MP8 and MP10 fleets
EOS-5.0 — FA-4
- ✓ Mack's recommended spec on 2021+ MP8s
- ✓ Lower viscosity for fuel economy
- ✗ Not for 2020-and-older MP8s
- → Two oils in the shop if you run mixed years
Simple rule: EOS-4.5 works in every 2010+ MP8. EOS-5.0 only goes in 2021 and newer. AMSOIL's heavy-duty diesel oils are CK-4 oils that meet Mack EOS-4.5; AMSOIL does not currently offer an EOS-5.0 oil.
What Is Mack EOS-4.5?
Mack EOS-4.5 is Mack's engine oil specification built on API CK-4, with Mack's own testing on top. It is the minimum spec for every 2010-and-newer MP7, MP8 and MP10. Mack lists approved oils in Service Bulletin 175-61, "Approved Oils – Mack Components," which any Mack dealer parts counter can pull.
Soot Control
Oil must keep EGR soot suspended so it can't thicken the oil or wear parts.
Oxidation Resistance
Oil must hold up to the heat of long drains and heavy loads.
Wear Protection
Oil must protect the valvetrain and liners over the full interval.
Shear Stability
Oil must hold its viscosity grade under heavy mechanical shear.
| Mack Spec | API Base | MP8 Use |
|---|---|---|
| EOS-4.5 | API CK-4 | Every 2010+ MP8; minimum on 2021+ |
| EOS-5.0 | API FA-4 | Recommended on 2021+ only |
| EO-O Premium Plus | API CJ-4 era | Older Mack spec, superseded by EOS-4.5 |
Best AMSOIL Oil for the Mack MP8
For every MP8, the Red Seal tech pick is AMSOIL Signature Series Max-Duty 15W-40 (DME), a CK-4 oil formulated to meet Mack EOS-4.5. Max-Duty 5W-40 (DEO) is the cold-climate pick, and Max-Duty 5W-30 (DHD) covers mixed fleets that need one oil for every make.
- Formulated to meet Mack EOS-4.5
- Also meets Volvo VDS-4.5 for the D13
- 6X more wear protection than Detroit's DD13 scuffing test requires
- Strong hot-temperature film protection (HTHS 4.5)
- Formulated to meet Mack EOS-4.5
- Cold cranking to −30°C vs −20°C for 15W-40
- Good choice for Canadian winter routes
- API CK-4, formulated to meet EOS-4.5 (not EOS-5.0)
- Also meets CES 20086, DFS 93K222, VDS-4.5
- Cold cranking to −30°C (−22°F)
Use the AMSOIL heavy-duty lookup to cross-reference your engine make, model, year, and emissions tier.
Use the AMSOIL Heavy-Duty Lookup →AMSOIL MP8 Oil — Which Tier Is Right for You?
Not every truck or budget calls for the same product. AMSOIL makes multiple diesel oil tiers depending on the job.
| Product | Protection Level | Drain Interval | Best For |
|---|---|---|---|
| Signature Series Max-DutyDME / DEO / DHD | Top-tier synthetic diesel protection | OEM interval; beyond it with oil analysis | Owner-operators and fleets maximizing uptime |
| Heavy-Duty SyntheticADO / ADP | Full synthetic protection | OEM interval | Operators wanting synthetic protection at lower upfront cost |
| Commercial-GradeSBDT / SBDF | Synthetic-blend upgrade | OEM interval | Fleets upgrading from conventional oil |
All three tiers are API CK-4 oils that meet the requirements of Mack EOS-4.5. Run Mack's interval for your duty cycle, and use oil analysis before going past it.
Why MP8 Fleets Should Run Oil Analysis
The MP8 runs EGR, and Mack shortens the interval when idle time goes over 30%. Mileage alone does not tell you the full story.
A basic oil analysis sample checks the numbers that matter:
- → TBN: remaining acid-neutralizing reserve
- → Soot: soot loading and viscosity risk
- → Wear metals: iron, copper, chromium, aluminum
- → Coolant contamination: early warning for cooler or gasket problems
Over 30% idle and Mack drops the MP8 to the next shorter interval. Long idle hours load the oil with soot and fuel without adding miles.
Oil analysis shows what idle is actually doing to your oil, truck by truck.
| Analysis kit | A fraction of one oil change |
| Early coolant leak detection | Major repair avoided |
| Confirmed drain extension | Fewer oil changes |
| Wear metal trending | Rebuild risk reduced |
Mack MP8 Engine Oil — Common Questions
From owner-operators, fleet managers, and shop techs running the MP8 in Mack Anthem, Granite and Pinnacle trucks across North America.