Mazda B, UN (USA / CAN)

Coolant capacity & service interval

Mazda B, UN (USA / CAN) coolant capacity ranges from 9,7 to 14,3 liters. Service intervals include checks at 15000 miles or 6 months, and changes at 50000 miles or 36 months and 100000 miles or 72 months. The data covers 10 configurations.

The configuration chart below lists fill volumes and service intervals for each engine and trim variant.

TypeSpecifications
B 2300 (2003-2007)
  • Use: Normal, yellow fluid
  • Capacity 9,7 liter (+ automatic transmission/transaxle)
  • Capacity 10 liter (+ manual transmission/transaxle)
  • Check 15000 miles/ 6 months
  • Change 50000 miles/ 36 months
B 2300 (2003-2007)
  • Use: First change only, yellow fluid
  • Capacity 9,7 liter (+ automatic transmission/transaxle)
  • Capacity 10 liter (+ manual transmission/transaxle)
  • Check 15000 miles/ 6 months
  • Change 100000 miles/ 72 months
B 3000 2WD (2003-2007)
  • Use: Normal, yellow fluid
  • Capacity 14 liter (+ automatic transmission/transaxle)
  • Capacity 14,3 liter (+ manual transmission/transaxle)
  • Check 15000 miles/ 6 months
  • Change 50000 miles/ 36 months
B 3000 2WD (2003-2007)
  • Use: First change only, yellow fluid
  • Capacity 14 liter (+ automatic transmission/transaxle)
  • Capacity 14,3 liter (+ manual transmission/transaxle)
  • Check 15000 miles/ 6 months
  • Change 100000 miles/ 72 months
B 3000 4WD (2003-2007)
  • Use: Normal, yellow fluid
  • Capacity 14 liter (+ automatic transmission/transaxle)
  • Capacity 14,3 liter (+ manual transmission/transaxle)
  • Check 15000 miles/ 6 months
  • Change 50000 miles/ 36 months
B 3000 4WD (2003-2007)
  • Use: First change only, yellow fluid
  • Capacity 14 liter (+ automatic transmission/transaxle)
  • Capacity 14,3 liter (+ manual transmission/transaxle)
  • Check 15000 miles/ 6 months
  • Change 100000 miles/ 72 months
B 4000 2WD (2003-2007)
  • Use: Normal, yellow fluid
  • Capacity 12,5 liter (+ automatic transmission/transaxle)
  • Capacity 13 liter (+ manual transmission/transaxle)
  • Check 15000 miles/ 6 months
  • Change 50000 miles/ 36 months
B 4000 2WD (2003-2007)
  • Use: First change only, yellow fluid
  • Capacity 12,5 liter (+ automatic transmission/transaxle)
  • Capacity 13 liter (+ manual transmission/transaxle)
  • Check 15000 miles/ 6 months
  • Change 100000 miles/ 72 months
B 4000 4WD (2003-2007)
  • Use: Normal, yellow fluid
  • Capacity 12,5 liter (+ automatic transmission/transaxle)
  • Capacity 13 liter (+ manual transmission/transaxle)
  • Check 15000 miles/ 6 months
  • Change 50000 miles/ 36 months
B 4000 4WD (2003-2007)
  • Use: First change only, yellow fluid
  • Capacity 12,5 liter (+ automatic transmission/transaxle)
  • Capacity 13 liter (+ manual transmission/transaxle)
  • Check 15000 miles/ 6 months
  • Change 100000 miles/ 72 months

Additional Notes

  • The Mazda B, UN (USA / CAN) 2003-2007 cooling system specifications cover three engine variants — the B 2300, B 3000, and B 4000 — each carrying a distinct coolant capacity range tied to transmission type.
  • The B 2300 with an automatic transmission holds 9.7 liters of coolant, while the manual transmission pairing raises that figure to 10 liters, reflecting the slightly different thermal load distribution between the two drivetrain configurations.
  • The B 3000, in both 2WD and 4WD configurations, shares identical coolant capacities: 14 liters with an automatic transmission and 14.3 liters with a manual transmission, making the B 3000 the highest-capacity variant across all three engine lines.
  • The B 4000, also available in 2WD and 4WD, sits between the B 2300 and B 3000 in terms of coolant volume, with 12.5 liters specified for the automatic transmission pairing and 13 liters for the manual transmission pairing.
  • Across all variants and drivetrain combinations, the manual transmission consistently requires a slightly larger coolant fill than the automatic transmission counterpart, with differences ranging from 0.3 to 0.5 liters depending on the engine.
  • All configurations share a uniform coolant check interval of every 15,000 miles or 6 months, whichever comes first, regardless of engine size or drivetrain layout.
  • Under normal use conditions with yellow fluid, the coolant change interval for all variants is 50,000 miles or 36 months, representing a standard mid-range service cycle for conventional coolant formulations of that era.
  • A separate first-change-only interval of 100,000 miles or 72 months is specified for yellow fluid across all B 2300, B 3000, and B 4000 configurations, doubling the normal change interval and applying exclusively to the initial factory-fill coolant charge.
  • The 100,000-mile / 72-month first-change-only interval reflects a long-life coolant strategy where the original factory fill is treated as a distinct service event before transitioning to the standard 50,000-mile / 36-month normal cycle.

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