MINI Cooper Engine Overheating

MINI Cooper Engine Overheating Vehicle Aplications:

  • 2002-2006 MINI Cooper
  • 2002-2006 MINI Cooper S
  • 2005-2008 MINI Cooper Convertible
  • 2005-2008 MINI Cooper S Convertible
  • 2007-2014 MINI Cooper
  • 2007-2014 MINI Cooper S

Road Tech Tip: The heater core, a small radiator, transfers engine heat into the passenger compartment. This also helps cool the engine. If your engine is ever running hot, turn your heater and blower on high. While uncomfortable, it may reduce the engine temperature enough to make it to the next stop.

Coolant-Antifreeze FAQ::
Q:What is the primary purpose of engine coolant?
A:The coolant absorbs heat created by the engine, then releases the heat as it passes through the radiator. The antifreeze in the coolant mixture has anti-corrosive chemicals to help prevent corrosion in the radiator and engine, also it contains a lubricant to help extend the life of the water pump, hoses, and seals.

Q:How does "Antifreeze" work?
A:The antifreeze lowers the freezing point of the water/antifreeze mixture, and prevents the coolant from freezing inside the engine, radiator and hoses in cold weather. It also raises the boiling point of the water/antifreeze mixture, and prevents the coolant mixture from boiling as the engine temperature gets hotter.

Q:What is the proper ratio of water to coolant?
A:Use a mixture of 50% antifreeze/coolant and 50% water in your cooling system unless your climate calls for a greater ratio than 1:1 ratio of water to coolant such as in the northern part of the country where winter temperatures are in the single digits or lower.
[Warning: many antifreeze/coolant on the shelf today are pre-mixed with water 50/50 - never dilute a premix coolant with additional water.]
We recomend using Genuine BMW Antifreeze/Coolant for your MINI Cooper.

Q:Will using more antifreeze help reduce heat better?
A:No, by using more than a 50/50 mixture it reduce the amount of heat transfering capabilities of the coolant mixture because the antifreeze does not conduct heat as readily as water. The more antifreeze you have in the system, the less heat it can transfer in hot climates.

Q:Can I use tap water to refill my coolant system?
A:No, it is always recommended to use distilled water in the coolant mixture to help prevent corrosion caused by the natural minerals in tap water.
We recomend using Redline Water Wetter mixed with distilled water as an alternative mixture in very hot climates because does a better job absorbing heat from the engine as in motorsport applications.(Not to be used in the winter months)

Q:How does the radiator work in my car?
A:Coolant that has absorbed engine heat flows from the engine's upper radiator hose through the radiator's interior tubes and dissipates heat into the air. The coolant is now lower in temperature and exits the radiator and flows back into the engine to absorb more heat while the engine is running.(Providing that the themostat has opened due to the coolant temperature - the coolant will not flow until the thermostat has opened.)

Q:How does the radiator or expansion tank pressure cap work?
A:The radiator or expansion tank cap allows build-up of water pressure in the cooling system and keeps the system closed. Heated coolant expands and builds pressure in the system up to the point of the cap's rated maximum pressure raising the coolant's boiling point. (Water's boiling point is at 212 Deg. F.) The boiling point of the water/antifreeze mixture is raised by 2.7 Deg. F. for each pound per square inch of pressure.

Q:How does the thermostat work?
A:The thermostat is a valve that opens and closes to control the flow of coolant from the engine to the radiator in order to regulate the temperature of the engine. If thermostat were removed, the engine would not heat up sufficiently to produce heat throught your car's haeter durring the winter months.

Q:How does the engine auxillary fan work?
A:The engine auxillary fan mounted on the radiator pulls air through the radiator when the car is idling. MINI Cooper engine fans are activated electricly operated by the control input from the engine's computer system.

MINI Cooper Overheating Problems:

MINI Cooper Engine Overheating Problem:Engine overheats while idling but does not overheat when driving:
Solution:Check the auxillary engine fan mounted on the radiator to verify it is activating when car is at idle. If the fan does not start running and the engine temerature gauge or warning light indicates temperature to high during idling, then the check the auxillary fan for obstruction & wiring for breaks. Further diagnosis requires checking the ECM for fault codes using a Peake Fault Code Reader & Reset Tool. [Warning: The auxillary fan will activate without notice even when the engine is not running. Do not place fingers or allow articles to get into the fan while leaning over it to check operation!]

MINI Cooper Engine Overheating Problem:Engine overheats while driving up hills or hot days only:
Solution:Check the thermostat's operation. It should open at the thermostat's specified temerature allowing coolant flow while driving or under load. Also, check the coolant-antifreeze mixture is appropriate for your climate. Check for coolant leaks while cooling system is under pressure. (This may require driving the car until the temperature starts to rise above normal, and then stopping the car to look in the engine compartment and under the car for leaks or drips.) Other possible causes could include: sepentine belt damage or slippage, idler pulley not keeping enough tension on the drive belt, internally corroded radiator tubes. Our Genuine BMW coolant-antifreeze is specially formulated to prevent internal corrosion and the build-up of silicate compounds on both the radiator and the engine internal surfaces.

MINI Cooper Engine Overheating Problem:Engine overheats quickly while idling or driving:
Solution:Check the thermostat's operation as it could be closed shut or damaged internally. Check water pump operation. Water pump internal impeller failure will cause a decreased amount of coolant flow. Check for a cracked cylinder head gasket allowing water to pass throuh to the combustion chamber into the engine oil. Check for water in the oil. (white or grey milky fluid) Check for air trapped in the coolant system causing improper function of the thermostat. Bleeding of the cooling system may be neccessary for proper thermostat function.

MINI Cooper Engine Overheating Problem:Engine overheats and keeps loosing coolant frequently:
Solution:Check for a leaking hose, gasket, water pump, radiator, heater core, head gasket or cracked cylinder head. Many times the leak is small and goes undetected because it is evaporating and does not leave a puddle under the car. If it's a cracked head gasket or cylinder head, check for visible white smoke from the exhaust or foam in the engine oil. If you cannot see a visual leak, the system can be tested with a cooling system pressure tester. Also, a faulty radiator cap may be allowing pressure to escape and affect the ability of the system to cool the engine properly.


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MINI Cooper S Fuel Cleaner

Products > MINI Replacement Parts > MINI Cooling Components

MINI Cooling Components

Water Pump
Part Number: 51315    
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Replacement Water Pump (more info)
Expansion Tank Cap
Part Number: 50816    
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Coolant Expansion Tank Cap (more info)
Outside Temperature Sensor
Part Number: 69214    
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External Air Temperature Sensor - for on board computer (more info)
Radiator
Part Number: 140962    
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Replacement Radiator (more info)
Expansion Tank
Part Number: 173626    
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This is A Genuine MINI Expansion Tank (more info)
Aluminum Expansion Tank
Part Number: 173627    
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Originally designed with racing applications in mind, this Aluminum Coolant Tank has become a much sought after replacement upgrade for the daily driven MINI. (more info)
Coolant Hose O-ring for 1" Fitting
Part Number: 115240    
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If you are only replacing a coolant tank, radiator, or thermostat you should make it a point to replace the hose end O-rings. If your planning on using the old O-rings you run the risk of have a new leak. (more info)
Coolant Hose O-ring for 1.125" Fitting
Part Number: 115246    
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If you are only replacing a coolant tank, radiator, or thermostat you should make it a point to replace the hose end O-rings. If your planning on using the old O-rings you run the risk of have a new leak. (more info)
Coolant Hose O-ring for 1.5" Fitting
Part Number: 115242    
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If you are only replacing a coolant tank, radiator, or thermostat you should make it a point to replace the hose end O-rings. If your planning on using the old O-rings you run the risk of have a new leak. (more info)
Coolant Hose O-ring for 2" fitting
Part Number: 115244    
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If you are only replacing a coolant tank, radiator, or thermostat you should make it a point to replace the hose end O-rings. If your planning on using the old O-rings you run the risk of have a new leak. (more info)
Antifreeze - Coolant (Genuine BMW)
Part Number: 300800    
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Genuine BMW Blue Coolant Antifreeze (1 gallon). This long term antifreeze / coolant is exclusively formulated and produced for BMW to protect your engine year-round. (more info)
Products > MINI Replacement Parts > MINI Cooling Components