The dark oily spot from your car on the porch means that an oil leak is highly probable. The possible location is any spot where two metals are joined by a gasket piece, although this is the tricky part to identify the right location of the leak. The sooner the leak is repaired, the better it is. Here is a simple guide to seal a leak. Follow the directions.
- Gasket (rubber, cork or a tube of gasket sealant)
The gasket on the valve cover has to be inspected for any signs of leaks, sludge or deposits. Before you make a decision to replace the gasket, tighten the bolts that clamp the valve cover to the gasket. By this way, you may come across a loose bolt which may be the source of leak. Use a screwdriver or a wrench for tightening.
If the leaks continue, then loosen every bolt and pry the valve cover from the gasket. A flat screwdriver might be needed for this for losing the immovable gasket. All the breather cables and the spark plug cables have to be removed.
By this time, the gasket may get hard and its pieces will start falling apart. This should be carefully done to prevent the pieces of torn gasket from dropping in the engine internals. When the valve cover pops up, a scraper can be sued for removing the remaining gasket which is still attached to the valve cover. High temp silicone has to be applied on the edge of the valve cover before the new gasket is positioned. The valve cover can be bolted now and apply reasonable force for tightening all the bolts. The new gasket will probably run for around 100000 km before the next change.
Now, the drain plug bolts have to be visually inspected for any signs of build up sludge as this may be a sign of worn out threads. It is a usual observable fact because every change of motor oil requires unbolting and installing that screw that wears out the thread soon.
Go ahead and inspect the oil pan and the oil filter. The oil pan is held by bolts and has a gasket for ensuring tight seal for preventing any oil leakage. The oil filter if probably not properly tightened can be resolved by increasing the rotating force of the filter. Use a torque wrench to tighten all the bolts. If the problem still continues, then a replacement gasket has to be scheduled.
First, all the motor oil has to be drained before dropping the pan. Use a flat head screwdriver to pry the pan free. The stubborn gaskets have to be scrapped off before proceeding to apply high temp silicone; it is similar to the valve cover procedure. Now the gasket has to be positioned in place and the pan has to be bolted. Finally, fill the engine oil and inspect for any sign of leakages.
This fairly simple Do-It-Yourself method will help you stay away from hassle of visiting a mechanic besides saving a good amount of money.