To replace a radiator:
- Drain all coolant from the radiator.
- If the coolant will not be reused, be sure to comply with local regulations for its disposal.
- Remove the radiator.
- Disconnect the radiator hoses from the engine. If the hoses are left attached to the radiator, they do not need to be marked for reassembly.
- Remove the radiator from the car.
- Install the new radiator and hoses and fill the cooling system with coolant.
- Make sure that the heater hoses are installed with the return line to the block coming from the heater core, not from the heater valve.
- These should have been marked during disassembly.
Replacing a radiator core
Cooling efficiency suffers if the tubes have become plugged or if the fins are corroded or broken loose from the tubes. Check the condition of the fins by rubbing something gently against them (be careful not to bend them). If they are in good condition, they will be rigid and not flake away.
When the cooling fin metal rots, the radiator will require a new core. Many radiator tanks are brass and are soldered to the copper radiator core. On copper/brass radiators, the top and bottom tanks are reused by soldering them to the new core. The filler neck is also soldered to the brass tank. This is done in a radiator shop.
The radiators on many newer cars have plastic tanks and vacuum brazed aluminum cores. It is especially important that these radiators be periodically maintained as they are more prone to corrosion/electrolysis than copper/brass radiators.