2016 BMW M5 Has A Coolant Leak

Diagnosing Coolant Leak Issues in Your 2016 BMW M5 and Effective Repair Strategies

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Reviewed by
Bo Fader
Written by RepairPal Car Genius
Updated January 14, 2025
0%
50% chance it's the
Loose Hose Connections
0%
25% chance it's the
Radiator
0%
25% chance it's the
Water Pump
The most common reasons a 2016 BMW M5 has a coolant leak are loose hose connections, a broken radiator, or a failed water pump.
  • Loose Hose Connections: Loose hose connections can lead to vacuum leaks or fluid leaks, resulting in poor engine performance or overheating.
  • Radiator: A damaged or clogged radiator can impede coolant flow, resulting in engine overheating and reduced cooling efficiency.
  • Water Pump: A failing water pump can lead to coolant leaks or overheating due to inadequate circulation of coolant in the engine.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

How much does it cost to fix a 2016 BMW M5 has a coolant leak?

Common Repairs

The total repair cost will vary based on the condition of your vehicle and the number of repairs needed to fix your symptom. Proper diagnosis will save you money by finding the exact repairs needed to fix your car right the first time.

When the head gasket begins to fail, the engine may have no symptoms at all. They only begin to occur when the leak has reached an engine oil passage, engine coolant passage or the engine cylinder.

When that happens, the engine may be very difficult to start, and run roughly when idling. There may be oil or coolant leaking, and the engine may begin to overheat, or at least run hot. At this point, there may be coolant in the engine oil pan — this will look creamy and lighter in color than the oil. Also, the radiator or engine coolant reservoir may have a gurgling sound, the presence engine oil, or smell of combustion. And the check engine light will come on.

The coolant being burned in the engine will produce white exhaust that smells sweet, like engine coolant. When the head gasket fails completely, the engine will overheat within minutes of starting, will stall and then won't restart.

A failing heater core may cause the car's interior to smell like engine coolant. The smell will become worse when the heater is turned on. The engine may also begin to run hotter until the vehicle is repaired.

The worst-case scenario is the engine overheating, which can cause extensive engine damage.

If the heater core is clogged, the air that blows when the heater is turned on will not be very hot.

Problems with the intake manifold gasket can create the following symptoms:

  • Illuminated check engine light
  • Erratic engine performance
  • Oil and coolant leaks
  • Poor gas mileage
  • Stalling

» LEARN MORE: Intake manifold gasket symptoms

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 coolant leak may be noted from the hoses. Coolant hoses can be damaged by oil leaks, or age. This will lead to swelling or cracking, it is suggested to replace the hoses before they begin leaking to avoid potential overheating.

The bad thermostat can cause two different sets of problems, depending on whether it's stuck open or stuck closed.

A thermostat that is stuck open can cause the engine to run colder than normal and turn on the check engine light. It may also cause poor fuel mileage and the heater to blow cool air.

A thermostat that is stuck closed will cause the vehicle to overheat. If a new thermostat doesn't resolve engine temperature problems, the cooling system needs to be checked for other issues.

» LEARN MORE: Signs of a bad thermostat, and how to fix it

The two most common signs of a bad pump are leaks and noises.

Leaking water pumps can result in damage to the drive and timing belts, and cause the engine to overheat. A failed water pump can be caused by other problems in the cooling system, such as a bad thermostat, radiator or head gasket.

What are the steps to diagnose a coolant leak in a 2016 BMW M5?

To effectively diagnose a coolant leak in your 2016 BMW M5, begin with a systematic approach that prioritizes simpler checks before moving on to more complex diagnostics. Start by examining the coolant level in the reservoir; a low level often indicates a leak. Next, inspect the area beneath your vehicle for any visible puddles of coolant, which typically appear in bright green or orange hues. If you observe steam or smoke emanating from the engine compartment, this could also signal a coolant leak. For a more thorough investigation, consider performing a pressure test on the cooling system, as this can help identify the precise location of the leak. Additionally, carefully inspect the hoses and connections for any signs of wear or damage, as these are common sources of leaks. Finally, pay close attention to the radiator, water pump, and expansion tank, as these components frequently contribute to coolant issues in BMWs. By following this structured diagnostic approach, you can efficiently identify and address any coolant leaks, ensuring your vehicle remains in optimal condition.

What are the common causes of a coolant leak in a 2016 BMW M5?

When dealing with coolant leaks in a 2016 BMW M5, it's essential to understand the common culprits that could be at play. One frequent issue is the failure of coolant hoses, which can degrade over time and lead to leaks. Additionally, the radiator itself is a critical component that may develop leaks due to wear and tear. Another area to inspect is the water pump, as a malfunctioning pump can also result in coolant escaping from the system. The thermostat housing is another potential source of leaks, often overlooked but crucial for maintaining proper engine temperature. Lastly, the radiator hoses, which transport hot coolant, can deteriorate and cause leaks as well. If you suspect a coolant leak, it's advisable to conduct a thorough inspection of these components to identify the source and address it promptly, ensuring the longevity and performance of your BMW M5.

How urgent is it to address the coolant leak in my 2016 BMW M5 to prevent potential engine damage?

Addressing a coolant leak in your 2016 BMW M5 is not just a matter of convenience; it is an urgent necessity to safeguard your engine's health. Ignoring the signs of a coolant leak, such as low coolant levels or the presence of coolant puddles, can lead to severe overheating, which may result in catastrophic engine damage. The longer you wait to diagnose and repair the leak, the more likely you are to face costly repairs that could have been easily avoided. The sweet smell of coolant is a clear indicator that something is amiss, and if left unchecked, the consequences can escalate quickly, potentially leading to engine failure. Therefore, it is imperative to act swiftly and address any coolant leak to maintain the performance and longevity of your vehicle, ultimately saving you from significant financial burdens down the line.

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