The Head Gasket in your Mini plays a vital role in your engine's combustion process, it also keeps the oil & the coolant from mixing together. It is found between your Mini's Cylinder Head & the top of your Engine cylinder block, when this essential part fails, an expensive repair bill is likely not far behind!

Unlike any other gasket in your Mini's engine, the head gasket simultaneously seals the oil, coolant and compression from the cylinders - making it the most stressed gasket within your engine. It withstands extremes of temperature, sealing the coolant galleries & the oil galleries, where they pass from block to head, providing a gas tight seal for the combustion chamber.

Unfortunately for Mini owners, diagnosing an issue with the head gasket can be a tricky thing to do, as the head gasket is almost entirely unseen on a fully assembled engine. With overheating being the main cause for a blown or failing head gasket, however damage to the gasket can also be caused by pre-ignition (pinking) - when fuel has combusted at the wrong time, resulting in pressure & excessive heat in the combustion chamber. A blown head gasket can also be caused by an incorrectly installed gasket, or if the head bolts are not correctly torqued down.

Check your head gasket if you notice any of the following:

  • White / milky oil: If a milky liquid can be seen around the Mini's oil filler cap, or on the dipstick, the coolant has possibly leaked in to your oil & mixed
  • White exhaust smoke: If  the coolant has leaked into the combustion chamber the exhaust gives off white smoke as it burns
  • Loss of power: A loss of engine power could be down to a perforation on the gasket, this causes pressure in the combustion chamber to decrease or to pass from one cylinder to the next between the face of the block and the head.
  • Water / sweet smell from exhaust: Leaks in the combustion system can lead to water or a sweet smell (antifreeze) from the Mini's exhaust
  • Overheating engine: The Mini's engine becomes prone to overheating if your head gasket has leaked coolant

We strongly advise against driving your Mini if your head gasket has blown, as doing so can cause your engine to overheat, leading to cracking & damage and a possibility of a seizure. This can ultimately cause irreparable damage! You'll also notice significant power loss.

The good news is you can prevent blowing the head gasket on your Mini:

  • Ensure your coolant fluid is topped up & that there are no leaks in your coolant system, ensure that you have the correct mix of antifreeze / summer coolant to prevent freezing of the cooling system
  • In winter check the condition of your pressure cap & the condition of all of the coolant hoses & connections.
  • Ensure that your fan belt is secure & is operating the water pump correctly
  • A correctly fitted head gasket
  • Ensure your head studs are in a good condition & torqued down correctly in accordance with the recognised technical data.

How much does it cost to fix if the head gasket blows roughly?

Typical cost of replacing a head gasket is :

  • Carburettor engine -   3 hours @ £55.00 per hour inc’ vat + parts used
  • Injection engines ( SPI & MPI ) 4 hours @ £55.00 per hour + parts used

Can you check your Head Gasket at home or does a garage have to do it?

If you have the equipment & the mechanical knowledge, it can be checked at home.

How do you check your Head Gasket?

Check the compression pressures, observe the engine temperature, check for water or oil leaks from the head gasket area & check how it runs.

If you replace your Head Gasket, do you have to replace any other parts too?

You will need to change the rocker cover gasket, thermostat gasket, manifold gasket & heater valve gasket (if fitted on the cylinder head). It's also recommend changing the oil, filter & the coolant.

We hope that this blog can give you a little advice on the Head Gasket in your Mini, don't forget - our team is available 9am – 5pm Monday to Friday to assist you with any questions you may have – or assistance you may need, please don’t hesitate to get in touch!