TECH TIP: 2002-2006 Mini Cooper R50 Engine Failure

Vehicles Effected:
  • MINI Cooper (2002-2006) with R50 Engine
  • MINI Convertibles (05-06)
We recently had a Mini Cooper R50 towed into our service department. The Vehicle is a standard Cooper R50 with CVT transmission. The car is totally stock with no modifications. Engine would not start, and had no compression. Being a CVT and knowing the cars history, this vehicle had not been driven hard or aggressively. However this engine did have a catastrophic engine failure due to owner neglect and poor maintenance.

It is very important to be aware of all lights and gauges on the dash. These are the only indicators on your dash letting you know the running condition of your engine. All modern engines are computer driven. The ignition system as well as the fuel system are very reliable and there are few moving parts. Engine designs have improved to a point that they seem to run flawlessly almost indefinitely. This extended reliability is what makes us forget that the engine under the hood need to be checked and serviced.

The 3 most important lights and indicators on your dash are, oil pressure light, alternator (battery) light, and engine temperature gauge. If either of the lights come on or the temp gauge goes into the red, you may be in for a $4000.00 or more engine repair. The simple rule is if these lights come on, pull to the side of the road and turn the engine off.

The Pistons in this photo indicate failure due to severe over heating. All of the piston rings are cracked, broken, or seized to the piston. Number 2 piston actually began to melt down as a result of detonation. The upper connecting rods had turned blue from extreme heat. My feeling is this vehicle had been run for many miles without water in the cooling system. As the vehicle ran in the red (over heat condition) the rings began to seize on the pistons.

This severe over heating eventually created a hot spot on the piston top edge which will begin melting down the aluminum. In the photo below you will see the beginning of the melt down process. In this case we found small spots of aluminum piston pieces fused to the cylinder walls.

To avoid these problems it is very important to learn and understand the lights and gauges on your dash. It is also important to get under the hood of your vehicle and get familiar with some of the common components that need checking periodically.

Understanding the lights on your dash: With the key in the ON position and engine OFF you will see the following lights illuminated on your dash.

This is what they indicate:

1) Oil Lressure Light: Should be illuminated with key on and engine off. Light must go off within 3 seconds of starting engine. There may be a slight delay if the engine is hot, or if oil is slightly low. Oil light flickering at Idle is an indication of low oil pressure.

Common Causes of Low Oil Pressure (view common causes here)

2) Alternator (Battery) Light: Should be illuminated with ignition on and engine off: Light must go out when car starts. Flickering light at idle, or glowing light, or light on with engine running indicated alternator is not charging or not turning. (note bulb must illuminate when key is on and engine is off for alternator to begin charging).

Common Causes for Alternator Not Charging Correctly (view common causes here)

3) Temperature gauge: This is measuring coolant temperature. In moderate outside temperature this gauge will operate in the middle, once the engine warms up. On a hot day, or in slow moving traffic you can expect the gauge to creep up a notch. If the gauge approached the red, pull over, stop the engine, do not continue driving! The important thing is be familiar with the normal range your temp gauge is operating at.

Common Causes for an Engine Running Hot! (view common causes here)

If your engine is running hot: Do not keep driving!

Be familiar with components under the hood and how to check them: (see below)

  1. Check Engine oil level
  2. Check Coolant Level
  3. Check and confirm that the serpentine belt is still in place and turning the alternator and water pump
  4. Check power steering fluid level
  5. Check power steering pump operation
  6. Check radiator auxiliary fan operation
  7. Check brake fluid level
  8. Check & add washer fluid (front wiper