Jaguar Mark X / 420 (EU)
Coolant capacity & service interval
Jaguar Mark X / 420 (EU) coolant capacity ranges from 13 to 14 liters depending on configuration. The data covers three configurations.
The configuration chart below lists fill volumes and service intervals for each engine and trim variant.
| Type | Specifications |
|---|---|
| 420G (1966-1970) |
|
| Mark X 4.2 (1964-1966) |
|
| Mark X 3.8 (1961-1965) |
|
Additional Notes
- The Jaguar Mark X / 420 (EU) coolant system capacities fall within a 13 to 14 liter range across all listed configurations, reflecting the large-displacement inline-six engines these vehicles carried.
- The Mark X 3.8 carries a cooling system capacity of 14 liters, identical to the Mark X 4.2 despite the difference in engine displacement between the two variants.
- The 420G, covering model years 1966-1970, lists a capacity range of 13 to 13.9 liters rather than a fixed value, indicating a slight variation within that specification rather than a single absolute fill figure.
- All three configurations list use condition as normal, meaning the capacities stated apply to standard operating conditions rather than severe-duty or first-change scenarios.
- The Mark X 3.8 (1961-1965) and Mark X 4.2 (1964-1966) share the same 14-liter cooling system capacity, suggesting the transition from the 3.8 to the 4.2 engine did not alter the cooling system volume requirement.
- A cooling system capacity in the 13 to 14 liter range is consistent with large executive saloons of the 1960s, where extended coolant passages through a long engine bay and a substantial radiator core contributed to higher total fluid volumes compared to smaller contemporary vehicles.