The Kubota GB18 coolant capacity is listed as 1.73 gal (6.5 L). It also lists coolant type ethylene glycol-based coolant, Kubota Genuine Coolant, and ASTM D3306 compatible and antifreeze mix Kubota recommends a 50: 50 ethylene glycol-based coolant-to-water mix for the GB18 tractor to protect against freezing and corrosion.
Kubota GB18 Coolant Capacity
| Coolant capacity | 1.65 gal (6.2 L) |
|---|---|
| Cooling system capacity | 1.73 gal (6.5 L) |
| Coolant type | ethylene glycol-based coolant, Kubota Genuine Coolant, and ASTM D3306 compatible |
| Antifreeze mix | Kubota recommends a 50: 50 ethylene glycol-based coolant-to-water mix for the GB18 tractor to protect against freezing and corrosion |
| Engine horsepower | 17 hp (12.7 kW) |
| Engine displacement | 1 L (61.1 cu in) |
Coolant Capacity Comparison Chart
Coolant capacity comparison
Engine horsepower comparison
Engine displacement comparison
Kubota GB18 Coolant and Engine Notes
| Coolant capacity note | For service planning, the Kubota GB18 should be treated as 1.73 gal (6.5 L) coolant capacity. That is a compact tractor cooling system where a normal premixed coolant jug may cover most of the refill |
|---|---|
| Coolant type note | Use the right coolant formula for the Kubota GB18: ethylene glycol-based coolant, Kubota Genuine Coolant, and ASTM D3306 compatible. Cheap wrong coolant is not a smart saving if it causes corrosion or deposits |
| Antifreeze mix note | For the Kubota GB18, the captured mix is Kubota recommends a 50: 50 ethylene glycol-based coolant-to-water mix for the GB18 tractor to protect against freezing and corrosion. Straight water is not the right long-term answer unless you are only flushing the system |
| Engine context note | Engine context for the Kubota GB18: engine horsepower 17 hp (12.7 kW) and displacement 1 L (61.1 cu in). Engine size helps explain why coolant capacity changes between models |
| Refill note | Coolant changes are simple but easy to do sloppily. On the Kubota GB18, plan around 1.73 gal (6.5 L) and confirm the final level after air works out of the system |
Kubota GB18 Coolant Capacity FAQ
What is the cooling system capacity of the Kubota GB18?
The Kubota GB18 cooling system capacity is shown as 1.73 gal (6.5 L). That is the number to use before draining the system.
What coolant type should I use in the Kubota GB18?
Use ethylene glycol-based coolant, Kubota Genuine Coolant, and ASTM D3306 compatible. The blunt rule is simple: match the manual’s coolant spec and do not mix unknown coolant formulas.
Should I use straight water in the Kubota GB18?
Not for normal long-term use. The Kubota GB18 should use Kubota recommends a 50: 50 ethylene glycol-based coolant-to-water mix for the GB18 tractor to protect against freezing and corrosion or the manual’s specified coolant mix so the system gets corrosion, freeze and boil protection.
Does old coolant matter in the Kubota GB18?
Yes. Old coolant can lose protection even if temperature looks normal. The listed service interval for the Kubota GB18 is the service interval in the operator manual.
What engine specs affect Kubota GB18 coolant capacity?
The captured engine context is horsepower 17 hp (12.7 kW) and displacement 1 L (61.1 cu in). Engine size is one reason coolant capacity changes between tractors.
Mistakes do happen. Tractor coolant specs can change by year, market, engine, radiator, cab/heater setup and service procedure. Please check the operator manual, decal information and official kubotausa.com website for official information before draining or refilling the cooling system.
