Heavy Diesel Coolant Capacity Matrix | Class 8 Radiator Specs
Factory OEM cooling system capacities for Class 8 trucks. Engine block & radiator volumes, coolant chemistry (OAT Red/ELC), and thermostat specs.
Class 8 Heavy Duty Diesel Coolant Fill Standards
Total cooling system capacity in a heavy-duty commercial truck includes the engine water jackets, radiator core, surge tank, heater cores, and auxiliary transmission / oil coolers:
| Engine Model | Engine Block Only | Typical Chassis Complete Fill | Recommended Coolant Chemistry | Thermostat Temp |
|---|---|---|---|---|
| Cummins ISX15 / X15 | 5.5 Gal | 13.5 Gal (51.1 L) | Heavy-Duty Extended Life OAT (Red/Nitrite-Free) | 180°F (82°C) |
| Detroit Diesel DD15 (GHG14 / GHG17 / Gen 5) | 5 Gal | 12 Gal (45.4 L) | Detroit Power Cool Plus (OAT Red) | 190°F (88°C) |
| Caterpillar C15 & C15 ACERT (6NZ / BXS / MXS) | 6 Gal | 14 Gal (53 L) | Cat ELC (Extended Life Coolant Red/Strawberry) | 190°F (88°C) |
| PACCAR MX-13 (EPA10 / EPA13 / EPA17 / EPA21) | 4.8 Gal | 11.5 Gal (43.5 L) | PACCAR Extended Life Coolant (Red OAT) | 185°F (85°C) |
| Detroit Diesel DD13 | 4.5 Gal | 11 Gal (41.6 L) | Detroit Power Cool Plus (OAT Red) | 190°F (88°C) |
| Caterpillar 3406E (5EK / 2WS / 1MM) | 5.8 Gal | 13.5 Gal (51.1 L) | Cat ELC (Extended Life Coolant Red) | 190°F (88°C) |
| Detroit Diesel DD16 (Heavy Haul 600 HP) | 5.5 Gal | 13 Gal (49.2 L) | Detroit Power Cool Plus (OAT Red) | 190°F (88°C) |
| Detroit Diesel Series 60 (12.7L / 14.0L) | 5 Gal | 12.5 Gal (47.3 L) | Heavy-Duty Nitrite-Free OAT Extended Life Red | 180°F (82°C) |
| Volvo D13 / Mack MP8 (12.8L) | 5.5 Gal | 13 Gal (49.2 L) | Volvo VCS Yellow OAT Extended Life Coolant | 180°F (82°C) |
| Cummins B6.7 / ISB6.7 (Medium-Duty) | 3.2 Gal | 7.5 Gal (28.4 L) | Fleetguard Compleat EG / Heavy-Duty OAT Nitrite-Free | 190°F (88°C) |
| Navistar International DT466 / DT466E (7.6L) | 4 Gal | 8.5 Gal (32.2 L) | Fleetrite Extended Life Coolant (Red OAT) | 180°F (82°C) |
| Caterpillar C7 / C7 ACERT (7.2L) | 3.8 Gal | 8 Gal (30.3 L) | Cat ELC (Extended Life Coolant) Strawberry Red | 190°F (88°C) |
| Cummins N14 / N14 Celect Plus (14.0L) | 5.5 Gal | 13 Gal (49.2 L) | Heavy-Duty Low Silicate with SCA / DCA4 Filter | 180°F (82°C) |
| Caterpillar C12 (12.0L) | 4.8 Gal | 12 Gal (45.4 L) | Cat ELC (Extended Life Coolant) | 190°F (88°C) |
| Caterpillar C13 / C13 ACERT (12.5L) | 5 Gal | 12.5 Gal (47.3 L) | Cat ELC (Extended Life Coolant) | 190°F (88°C) |
| Cummins L9 / ISL9 (8.9L Vocational) | 4.2 Gal | 9 Gal (34.1 L) | Fleetguard Compleat Extended Life OAT Nitrite-Free | 180°F (82°C) |
| PACCAR MX-11 (10.8L) | 5 Gal | 12 Gal (45.4 L) | PACCAR Extended Life Coolant (Red Organic Acid Technology) | 185°F (85°C) |
| Cummins 5.9L 24-Valve / CR (ISB5.9) | 2.8 Gal | 6.5 Gal (24.6 L) | HOAT (Zerex G-05) / Heavy-Duty Low Silicate with SCA | 190°F (88°C) |
| Caterpillar 3406B / 3406C Mechanical (14.6L) | 5.2 Gal | 13.5 Gal (51.1 L) | Conventional Heavy Duty with SCA (DCA4) / Cat ELC | 180°F (82°C) |
| Mercedes-Benz MBE 4000 / Detroit MBE4000 (12.8L) | 5 Gal | 12.5 Gal (47.3 L) | Heavy-Duty Nitrite-Free OAT (MB 325.3 / 326.3) | 181°F (83°C) |
ASTM D6210 Nitrited OAT vs Silicated Extended Life Coolant Chemistry
Heavy duty diesel engines equipped with Selective Catalytic Reduction (SCR) and Diesel Particulate Filters (DPF) mandate API CK-4 or FA-4 low-SAPS engine oils. Pre-fill replacement oil filter canisters with clean engine oil before spinning on to prevent dry-start bearing cavitation.
Always verify oil dipstick levels after running the engine for 5 minutes at idle and allowing a 15-minute drain-back period on level ground. Extreme cold climate operations require SAE 5W-40 or 0W-40 synthetic formulations.
Cooling System Vacuum Fill Protocols, Deaeration & Refractometer Testing
Class 8 commercial diesel cooling systems must be refilled using an Airlift-style vacuum fill system to pull a minimum of 25 in-Hg vacuum prior to coolant intake. Vacuum filling eliminates air locks in EGR coolers, turbocharger bearing housings, and cylinder head water jackets that cause localized overheating and cracking.
Verify freeze and boil protection using an optical refractometer rather than hydrometer test strips. A 50/50 ethylene glycol and deionized water concentration provides freeze protection down to -34°F (-37°C) and boiling protection up to 265°F (129°C) under a 15-psi radiator cap.
Frequently Asked Questions & OEM Service Guidelines
Verified answers according to official factory service literature and heavy-duty maintenance procedures:
Q: How do I calculate Diesel Exhaust Fluid (DEF) consumption?
Modern EPA10-EPA24 heavy diesel Selective Catalytic Reduction (SCR) systems consume DEF at a rate of 2.0% to 3.0% of total diesel fuel burned (approximately 2 to 3 gallons of DEF per 100 gallons of fuel).
Q: How do I test a J1939 CAN bus datalink circuit with a multimeter?
With vehicle batteries disconnected, measure resistance across diagnostic port pins C (CAN-Hi) and D (CAN-Low). A healthy circuit with both 120-ohm terminating resistors intact will read exactly 60 ohms (+/- 3 ohms).
Related Heavy Diesel Engineering Tools
Cross-reference other factory specifications and diagnostic tools for commercial diesel engines: