Would overfilling the coolant reservoir way above the maximum line to the top, increase the pressure inside the radiator causing the radiator to spring a leak? I know this will cause the reservoir to spill fluid out but would it cause harm to the radiator?
[b]No.
Tester[/b]
No. Coolant reservoirs have overflow hoses specially designed to let excess coolant and pressure out, in order to prevent damage to the radiator or other hoses.