To find the accurate capacity, you should consult your owner's manual. This is the most reliable source.
Alternatively, you can:
* Check the radiator: Look for markings on the radiator itself; sometimes the capacity is printed on it.
* Consult a repair manual: Repair manuals specific to the 2002 Pontiac Bonneville SE will usually list the cooling system capacity.
* Contact a Pontiac dealer or auto parts store: They might have access to this information.
Keep in mind that adding coolant is usually done with a 50/50 mix of coolant and distilled water, not pure coolant. Always refer to your owner's manual for the correct coolant type and mixing ratio.