Mini Water Pump Friction Drive System

Mini Water Pump Friction Drive System

The tensioner is able to disengage the water pump until the engine has reached a specific temperature.

One of the more interesting drive belt arrangements can be found on the Mini Cooper with the 1.6L Tritec engine. The new four-cylinder engine had a surprise for technicians when it came time to replace the water pump. 

The water pump has what looks to be a belt around the pulley but is actually rubber bonded to the outside. The water pump is turned by a metal wheel driven by the crankshaft pulley – this  wheel is what transfers the motion of the crankshaft to the water pump. 

This innovative tensioner is called a friction wheel drive system. The tensioner is able to disengage the water pump until the engine has reached a specific temperature. On a cold engine that is turned off, the tensioner will feel a little loose and you might be able to turn the pump by hand.

When the engine management system engages the water pump a small electric motor inside the tensioner changes the length of tensioner. The wheel is pulled onto the back of the belt on the crankshaft and water pump pulley.

If you need to replace the belt or water pump, you need to disengage the tensioner. To release the tension, a tab first needs to be pulled out. The main problem that can occur is the rubber on the outside of the water pump can wear out or come off the wheel. This can cause noise and possible damage to the tensioner and even to the back of the drive belt. If the water pump or wheel on the tensioner seizes, it can cause a flat spot on the pulley and can also cause damage to the drive belt. Some aftermarket suppliers have improved the rubber on the pulley so it will not separate. 

In 2008, Mini stopped using the Tritec engine. 

You May Also Like

A Deep Dive on Crankshafts at Callies Performance Products

Learn how the heart of the engine’s rotating assembly is designed, manufactured and installed.

In this educational video, Engine Builder's Greg Jones learns all about designing and manufacturing engine crankshafts. He visited Callies Performance Products in Fostoria, OH recently and sat down with Callies President Heath Norton, Sales Manager Brook Piper and engine builder Billy Briggs of Billy Briggs Racing Engines to discuss the latest in crankshaft technology, trends and manufacturing. Check out this episode of Intellectual Horsepower brought to you by Callies Performance Products.

Mercedes-Benz Engine Oil Leaks

Mercedes makes a fine product, but certain repairs will emerge as trends over time.

Freeze Frame Diagnostics

Freeze frame data is a “snap shot” of when the code occurs of the specific sensor PIDs.

Five Spark Plug Service And Replacement Tips

Most articles will tell you to use a torque wrench, but they never explain why.

How Belts, Tensioners And Misfires Are Connected

Modern crankshaft position sensors measure more than the position of the crankshaft.

Other Posts

Why Engine Coolant Replacement May Be Necessary, Not Optional

Look at the condition of the additive package and the freezing point to justify coolant replacement.

ABS Diagnostics

ABS is the foundation of the ESC system.

Volkswagen Engine Misfire Diagnosis

Misfire faults have been related to conditions like loose/damaged electrical connections, poor circuit grounds and more.

Knock Sensor Diagnostics

The knock sensor is not the only sensor responsible for detecting engine knock.