Holden Brougham, HK/HT/HG

Coolant capacity & service interval

Holden Brougham, HK/HT/HG models utilize coolant with a capacity range of 8,86 to 9,1 liters. The data covers 3 configurations.

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

Type	Specifications
Brougham, HT 308 HC (1969-1970)	Use: Normal Capacity 9,1 liter Capacity 8,86 liter (with automatic transmission)
Brougham, HG 308 HC (1969-1970)	Use: Normal Capacity 9,1 liter Capacity 8,86 liter (with automatic transmission)
Brougham, HK 307 (1968-1969)	Use: Normal Capacity 9,1 liter Capacity 8,86 liter (with automatic transmission)

The Holden Brougham HK 307, produced in 1968-1969, carries a cooling system capacity of 9.1 liters when paired with a manual transmission.
When the HK 307 is fitted with an automatic transmission, the cooling system capacity drops slightly to 8.86 liters, reflecting the reduced coolant volume needed when the transmission cooler circuit alters the overall thermal management layout.
The HG 308 HC and HT 308 HC share identical cooling system capacities with the HK 307, both specifying 9.1 liters for manual transmission variants and 8.86 liters for automatic transmission variants.
The 0.24-liter difference between manual and automatic transmission configurations across all three variants is consistent, suggesting a standardized adjustment tied to the automatic transmission cooling circuit integration rather than engine-specific factors.
All three variants list a single use condition of normal, meaning the stated capacities apply to standard operating conditions without a separate severe-use interval or fill specification.
The 9.1-liter figure represents a service fill capacity, indicating the volume required when refilling the cooling system during routine maintenance rather than a full overhaul drain-and-fill procedure.