Additive For Oil Leaks are chemicals added to your engine oil that try to stop leaks. They do this by filling in small holes in Oil Seals and by causing Oil Seals to expand/soften. Only problem with them is sometimes they make the Oil Seal expand too much which cause the Oil Seal to destroy itself. This will make a small oil leak into a big oil leak.

Valve Cover is attached to top of engine (cylinder head). It covers the valves which are soaked in oil. Valve Cover Gasket seals the Valve Cover to prevent oil escaping. Valve Cover Gaskets wear out after a few years and allow oil to escape down side of engine.

Valve Cover Gasket Fix

Oil Pan contains the oil used by engine to keep engine parts free to move. Oil Pan is attached to bottom of engine. Oil Pan Gasket is used to stop engine oil from escaping from Oil Pan. Oil Pan Gasket wears out after a few years and allow oil to escape down the side of the Oil Pan. 

Replace Oil Pan Gasket

Oil Filter removes any dirt from engine oil as the oil is pumped around the engine. Dirt ends up in oil as engine parts wear and those worn bits get carried off in the oil. Oil Filters not screwed on tightly enough to the engine can cause oil to escape.

Oil Drain Plug allows oil to be drained out of the Oil Pan. Oil needs to be changed in an engine regularly. Drain Plug can get damaged and worn out. Where the drain plug goes into the Oil Pan can also get damaged. Damaged or dirty Drain Plug will allow oil to escape from the oil pan.

Drain Plug Fix

Main Seal stops oil from escaping from the front of the crankshaft as the engine runs. Main Seal is located behind the engine pulley that has a belt or belts running off it. To fix, the Main Pulley would need to be removed from the engine and this pulley is on very tight.  Difficulty of repair is based on how easy it is to access the Main Pulley and how tight the bolt or nut is that holds the Main Pulley on.

Rear Seal stops oil from escaping from the rear of the crankshaft as the engine runs. Rear Seal is hidden by the transmission as this is where the transmission connects to the engine. If Rear Seal is bad, oil will come out between the Transmission and Engine. To fix the Transmission would need to be removed from the engine to be able to access the seal.

Camshaft Seal prevents oil from getting onto timing belts. Unlike Timing Chains, Timing Belts will be damaged should oil get onto them. Camshaft Seals wear out over time and will cause oil to appear on the Timing Belt side of the engine. To fix, the Timing Belt cover would need to be removed along with the Timing Belt and the pulley in front of the seal. Once they are removed then the Seal could be replaced. If the Timing Belt is not installed back correctly in that all the pulleys are correctly aligned then the Car Engine can be destroyed.

Timing Chain is covered in oil from engine. Timing Chain Cover is usually on the same side of the engine as the Main Seal. To prevent oil escaping, Timing Chain Covers use a Timing Chain Gasket. When a Timing Chin Gasket fails oil will start to appear outside of the Timing Chain Cover. Sometimes the Timing Cover Gasket can be replaced without needing to remove the Main Pulley. If the Main Pulley needs to be removed the process can be difficult since the pulley can be on very tight.

Crankcase Breather allows pressure which may build up in the oil pan to escape. When the pressure escapes, it brings oil with it. Over time the Crankcase Breather Tube can fall apart allowing the oil air mixture to escape onto the Valve Cover. To fix, replace with similar size and shape hose. If the right shape of hose cannot be found then another hose can be used with a metal coil that goes around the hose to keep it from collapsing as the hose is bent into the correct shape. The metal coil is available from auto part stores. 

Oil Cap allows engine oil to be added to an engine. Over time an Oil Cap can wear out or be lost allowing oil to escape from the Valve Cover. To fix, replace the Oil Cap.