To find the exact capacity for your specific Fiat Ducato 1.9 diesel, it's best to:
* Check your owner's manual: This is the most reliable source of information.
* Look for a sticker: Sometimes the coolant capacity is indicated on a sticker under the hood.
* Consult a Fiat mechanic or parts dealer: They will have access to detailed specifications for your vehicle.
Don't rely solely on online forums or general guides, as the capacity can differ. Always refer to your vehicle's documentation for the precise amount.