BMW 740i Radiator Replacement Cost

The engine generates heat when it is running; this heat must be removed to prevent damage to the engine. Coolant circulates throughout the engine and absorbs this heat. The water pump pushes the coolant through the radiator (where it is cooled) and returns it to the engine once more to absorb the engine’s heat, before returning it to the radiator to be cooled again. When a vehicle is traveling fast, rushing air flows through the radiator and cools the engine. When a vehicle is in stop-and-go traffic or stuck at a traffic light, the engine’s cooling fan pushes air through the radiator.

A failing radiator can cause the engine to run hot or overheat.

Most radiators are made of metal and plastic. The plastic parts can become brittle and crack over time, thus requiring replacement of the radiator.

A failing radiator can cause the engine to run hot or overheat. Most radiators are made of metal and plastic. The plastic parts can become brittle and crack over time, causing a leak of coolant (typically green or pink in color). All manufacturers have a recommended service interval for coolant renewal. As the coolant ages, the additives breakdown and being to form solid deposits. These deposits will build up in the passages of the cooling system and will eventually clog components, including the radiator. A leaking or clogged radiator must be replaced. Some automatic transmission cars will also have a transmission cooler integrated into the radiator. Lines going to and from the transmission circulate transmission fluid to help cool the transmission in heavy duty applications such as towing or off-roading. If this integrated cooler fails, it can allow transmission fluid and coolant to mix. This will causing shifting issues in addition to overheating.

A sub-performing Radiator has far reaching effects. An inoperative heater, loss of coolant, or engine damage from overheating could occur. Overheating causes severe damage to an engine, including failure of the head gasket. Continuing to drive an overheating vehicle may disable the motor.

Replacement intervals vary greatly by vehicle and driving conditions. We typically see the radiator replaced at approximately 80,000 miles. While the radiator does not wear the same as a belt or brake pad, the repeated heating and cooling cycles the radiator experiences will eventually cause the degradation of its plastic end-tanks and seals.

A comprehensive inspection of the entire cooling system will be performed, including the water pump, heater hoses, cooling fans, and thermostat. With the engine off, the technician may perform a pressure test to ensure the cooling system is sealed. Radiator hoses will be inspected and should be replaced if old or leaking. Brittle or oil soaked hoses will fail after radiator replacement, necessitating additional repairs. If the engine has overheated the shop will inspect for signs of engine damage. Modern engines commonly have composite (plastic) parts such as intake manifolds and thermostat housings that can warp from engine overheating. These parts, along with the head gasket, should be checked for leakage.

To replace the Radiator, the technician will drain the coolant from the cooling system and remove the Radiator and radiator hoses from the vehicle. This may also require removal of plastic shrouds and other engine bay cladding to reach the part. Where applicable, the cooling fan switch and electric cooling fan assemblies are transferred to the new Radiator. Once the new Radiator is installed, the cooling system is refilled with fresh coolant and the system is bled of any air, then rechecked to ensure all leaks have been fixed.

The entire cooling system should be inspected and tested when the radiator is replaced.