Are you experiencing an oil leak through the crank seal in your Mini? Minis that have gathered mileage have a greater tendency to develop oil leaks as their crankshaft seals wear down and break. This could happen for a variety of reasons.

A crank seal is attached to the front of the engine. Its purpose is to seal the end of the crankshaft together with the timing cover. It is usually made of metal and rubber or silicone.

The seal is a simple component with a very important purpose. It keeps oil from leaking outside the crankcase. As the crankshaft rotates, it tosses a lot of oil around the crankcase. The crank seal keeps this oil intact, avoiding leaking outside the crankcase.

In the event the seal has failed, the oil will leak out of the crankcase, leading to serious damage to your engine. The following are familiar signs of a crank seal oil leak:

●      An oil leak: When you notice a puddle of oil accumulating under your Mini, it is probably a leaking crank seal. You will notice the oil under the front of the engine block or at the back of the engine block where the seals are located.

●      High mileage: If your Mini is approaching high mileage, upwards of 100,00 miles, the crankshaft seal is approaching the end of its recommended service life. It is important that you service your crankshaft seal according to the recommended service interval. This will help you prevent the seal from failing.

Reasons for a Crank Seal Oil Leak

The front crank seal rides against the harmonic balancer and is prone to failure. This is because of vibration and engine heat that affect it with time. The failure of this seal allows oil to leak into the engine front, which in turn affects the serpentine belt, causing a squeaking sound and further alternator performance issues.

The following are some of the reasons behind the crank seal oil leak:

●      Wear and tear: As we had discussed above, the lifespan of a crank seal is usually 100,000 miles or thereabout. If your Mini has come to that mileage, then it is advisable that you replace it. Manufacturers recommend a certain interval for replacing the seal, but when you click that mileage, it is important that you change the seal.

●      Improper installation of the seal: An improperly-installed seal will cause oil to leak. This could be after servicing or if the seal was replaced. Improperly-installed seals can cause an oil leak and further a shortage of oil in the engine. This could hinder the proper performance of the engine and, in worst-case scenarios, an engine failure.

●      Too much oil on the engine's inside: Mini manufacturers provide a guideline on how much oil it must fill and you have to strictly adhere to these guidelines. It is a problem if you fill your engine with oil over the recommended amounts. As the crankshaft rotates, it will force the oil out of the crank seal, hence causing a leakage. On the other hand, too little oil will cause wear and create leaks in other places as well.

●      Seal damaged during a rebuild: Removing a crankcase during repair is a tough job. Most times, it cannot be removed without causing some damage to other internal components, including the crank seal. In case the seal is damaged during this tedious process, installing it back will mean that an oil leak is inevitable. The seal must be inspected before putting it back.

●      Other symptoms: Your engine makes a humming sound, you notice oil leaks in your driveway or underneath your engine, you notice oil coming out sporadically, you spot a stain where the seal is located inside the car's engine compartment, or the seal gives off an oily smell when heated, then you need to visit our certified garage to diagnose the fix the problem.

M Service for Your MINI

At M Service, we offer the residents of Walnut Creek, Alamo, Concord, Danville, Lafayette, Martinez, Moraga, Orinda, and Pleasant Hill specialized care for Mini Coopers and other European import vehicles at pocket friendly prices. We have dedicated ourselves to providing quality repair work at affordable rates.

We specialize in all models of:

●      Audi

●      BMW

●      Land Rover

●      Mercedes

●      MINI

●      Porsche

Our ASE Certified Mechanics undergo quarterly training for and use factory-grade tools and equipment with dealer level diagnostics to ensure you always get the best from us. Call us at (925) 932-8744

 or visit us at 2008 Mount Diablo Blvd in Walnut Creek, CA. We are Open Monday through Friday from 8:00 AM to 5:00 PM.

* Mini Cooper Car image credit goes to: jozzeppe.