How To Clean Oil Off Engine Parts

The engines used in MINI R56 cars are MINI New Generation engines. MINI New Generation engines are 1.6 liters in displacement, with turbocharged and normally aspirated versions. All aluminum two-piece crankcase construction keeps the weight down, while technology like adjustable camshaft angle and variable valve lift help to keep the engines efficient.

With the new engine design, new sealing technology is needed. The crankshaft seal is a good example of this. It is made of Polytetrafluoroethylene (PTFE). Low friction and minimum power consumption are the main advantages of MINI utilizing a PTFE oil seal. Other benefits include, no sealing problems with dry operation or insufficient lubrication, an operating range of -130°C to +200°C, and a low breakaway torque after standstill.

Other parts of the engine are sealed with molded rubber profile gaskets. These gaskets dry out over time, allowing engine oil to leak. For example, the valve cover gasket uses a molded rubber profile gasket; it leaks at the front and sides. Sometimes at the curve of the cylinder head where a dab of silicone sealant is used to ensure a good fit. The valve cover can also leak from the crankcase breather (along the center near the coils) and crank at the fastener bores.

In this article, I'll go over how to pinpoint the source of an engine oil leak. Problem areas, components and tips on narrowing down the culprits are in the following text. With any leak, it helps to clean the area and monitor it for fresh oil.

Keep in mind that when your car was serviced before, parts may have been replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have, so be prepared with different size sockets and wrenches.

Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If you're working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Do not work on your vehicle if you feel the task is beyond your ability.

Vehicle models change and evolve, as they grow older, so the vehicle shown in our illustrations may vary slightly from yours. If something seems different, let us know and share your info to help other users. Do you have questions or want to add to the article? Leave a comment below. When leaving a comment, please leave your vehicle information.

Lift and support the front of your vehicle. See our tech article on Jacking Up Your MINI.

Figure 1	This photo shows the top of a normally aspirated engine. The trouble with an oil leak is it usually spreads all over the bottom of your vehicle, making it hard to determine where the source is. Start by following the oil, you will notice some of the oil on the engine is darker and dirtier; this is the oil furthest from the leak. Follow the oil toward the cleaner area, sometimes even spotless with just a coating of light colored oil. Look for leaks at the right side (red arrow) of the engine from below. Always suspect the crankshaft seal, as it can fling oil up and all over the side of the engine. At the front of the engine (green arrow) the problem would be the oil filter housing, or the valve cover. If a leak at the front of the engine seems to come from the top of the transmission bell housing, check if the sealing O-ring at the vacuum pump is leaking down the left side of the cylinder head (yellow arrow). Large Image \| Extra-Large Image
Figure 2	This photo shows the top of a turbocharged engine. The trouble with an oil leak is it usually spreads all over the bottom of your vehicle, making it hard to determine where the source is. Start by following the oil; you will notice some of the oil on the engine is darker and dirtier; this is the oil furthest from the leak. Follow the oil toward the cleaner area, sometimes even spotless with just a coating of light colored oil. Look for leaks at the right side (yellow arrow) of the engine from below. Always suspect the crankshaft seal as it can fling oil up and all over the side of the engine. At the front of the engine (red arrow) the problem would be the oil heat exchanger or oil filter housing, or the valve cover. If a leak at the front of the engine seems to come from the top of the transmission bell housing, check if the sealing O-ring at the vacuum pump is leaking down the left side of the cylinder head (green arrow). Large Image \| Extra-Large Image
Figure 3	Starting at the front of the engine. Note the oil residue down the front of the engine and transmission bell housing (red arrows). Note the darker oil residue surrounding the area, but the center is clean, almost washed off by the oil leak. When looking for a leak, follow this clean area up, until you find the source. The source will usually be indicated by clean light colored oil, or sometimes where the leak stops. Large Image \| Extra-Large Image
Figure 4	In the previous photo the oil leak stops at the heat exchanger (red arrow). Note the light staining on the exchanger and how the leak doesn't go any further up on the engine. For this repair the heat exchanger and oil filter housing gaskets would be replaced. Large Image \| Extra-Large Image
Figure 5	This photo shows an oil leak at the right side of the engine, surrounding the crankshaft pulley (red arrow). The source here could be the crankshaft seal (most common) or from a leak at the valve cover. See the following photo for more info. Large Image \| Extra-Large Image
Figure 6	When diagnosing a problem with the crankshaft seal you are dealing with oil being flung around the side of the engine. Remove the drive belt and inspect the side of the engine. Look for oil starting low (green arrow) and lessening as it moves up (red arrow). On my subject vehicle, there is very little oil near the cylinder head (red arrow). This means the leak is most likely the crankshaft seal, as the oil radiates from the pulley and doesn't come from above. If you find a leak at the right rear corner of the engine, check if the engine oil is being flung from the drive belt to the backside of the engine. On early engines, some timing chain tensioners would leak, however this problem was mostly dealt with under warranty mileage periods. It is still a good idea to check the tensioner to see if oil is seeping out of the sealing washer. Large Image \| Extra-Large Image
Figure 7	At the bottom of the engine an oil leak can be from the oil filter housing as previously noted, or driveshaft axle seals. Although not an engine oil leak, these seals are often misdiagnosed as engine oil leaks. Note the wet oil stained area around the right axle and the fresh oil leak at the bottom of the bell housing (red arrows). Large Image \| Extra-Large Image
Figure 8	Leaks at the top of the engine are usually from the valve cover. Constructed of plastic and sealed to the cylinder head using a rubber profile gasket, the valve cover can leak a few different ways. Check for oil leaking from the seam at the cylinder head but no stains at the top (red arrow). This would indicate a gasket issue. Oil leaking at the center could be a faulty breather assembly, internal to the valve cover. Oil from the breather can also fill the center bolts holes (yellow arrows). Now keep in mind, the valve cover can also crank in the areas of the fasteners, creating an oil leak. If you suspect the crankcase breather or the cover has cracked, remove it and inspect it. For either of these issues, you will have to replace the valve cover. Large Image \| Extra-Large Image