If you notice oil stains on your porch after leaving your car overnight, an oil leak is highly probable. Now the tricky part is to identify the exact location of the leak. Any spots where two metals are held together by a piece of gasket could be a potential leak source.
Inspect the gasket on the valve cover for any signs of deposits, sludge or leaks. Before making decision to replace the gasket, try tightening the shoulder bolts which clamps the valve cover to the gasket. You might just come across a loose bolt and that is where the source of leak is from. Use a socket wrench or a screwdriver to perform this job.
If leaks continue, loosen all bolts and pry the valve cover from the gasket. The use of a flat head screwdriver may come handy in loosing the stubborn gasket. Remove all the spark plug cables and breather cables.
By now, the gasket may have hardened and bits and pieces of it will start to fall apart. Do this carefully so that the pieces of torn gasket do not drop into your engine internals. Once the valve cover pops up, use a scraper to remove the remaining gasket which is still attached to the valve cover. Apply high temp silicone on the edge of the valve cover before positioning the new gasket on. Bolt on the valve cover and use moderate force to tighten all the bolts. The new gasket will last for another 100000 km at least before the next change out.
Now, visually inspect the drain plug bolts for any signs of accumulated sludge because that may be a sign of worn of threads. It is a normal phenomenon because every change of motor oil requires unbolting and installing that screw and that soon wears out the thread.
Proceed to inspect the oil filter and the oil pan. The oil filter probably not properly tightened and can be resolved by increasing the torqueing force the filter. The oil pan is held by bolts and has a gasket to ensure tight seal thus preventing oil seepage. Try tightening all the bolts using a torque wrench. If the problem persists, a replacement gasket must be scheduled.
Firstly, you must drain all the motor oil before dropping the pan. Pry the pan free using flat head screwdriver. Similar to the valve cover procedure, scrap off stubborn gaskets before proceeding to apply high temp silicone. Position the gasket in place and bolt the pan on. Lastly, fill up the engine oil and observe for any sign of leaks.
This simple DIY on how to fix an oil leak saves the hassle of visiting your mechanic plus it will be light on your wallet.