Car Engine Oil Leaks
Any engine oil leak is not normal, when you notice oil underneath your car it means an engine oil leak has developed. Inside the engine there are two states of oil, pressurized and non-pressurized. Oil leaks that are not pressurized tend to be less aggressive. Oil that is pressurized will leak more when the engine is running, while non-pressurized oil leaks tend to be steadier. Always check the engine oil level before you start, and if your engine is dirty it is a good idea to clean the engine before so you can locate the exact source of the leak. Use a good degreaser like 409 or equivalent. Always clean an engine cold to avoid steam.
Steam is the cause of many electrical problems after an engine has been cleaned. Try to inspect the engine yourself to get an idea of where the oil is coming from. This will help you estimate the repair if you are going to have the oil leak repaired. Oil leak repairs can vary greatly so it's best to get a second opinion if the repair estimate is extreme. Use a flash light to pin point the source of the leak, then formulate a plan to repair it. When inspecting for engine an oil leak always start at the top of the engine and work your way down. We have listed common causes for oil leaks below.
Car oil leak Guide
Step 1 - The engine oil fill is used as a port to add oil to the engine. If this cap is left off it will cause engine oil to be expelled from the port when the engine is running. With the engine off lift the hood and located the engine oil fill port. Once this port has been located check the cap and its condition. If the cap is missing replace the oil fill cap with a new unit. If the oil cap is leaking remove the cap and replace the cap seal. Clean the area and recheck for the leak after a short operation period. Even though the engine oil is not under pressure internal engine pressure can force oil out of this port.
Step 2 - The engine oil filter is used to filter engine oil of carbon and other by products created by the engine and the combustion process. This oil filter is in direct connection with the engine's oil pump and is subject to high oil pressure. One of three things generally occurs when oil leaks from this area. First and most common is the oil filter is not installed properly. The filter either is not tight enough or the old oil filter gasket was not removed. When there are two gaskets or the filter is not tight enough the oil filter cannot seal. These problems can surface long after the filter replacement. Finally the oil filter itself is leaking, but this doesn't happen very often.
Step 3 - Theoil drain plug is used to remove the oil from the engine when a service is performed. The drain plug is a threaded flanged plug that uses a sealing washer to contact the oil pan. This seal is what keeps the engine oil from leaking out. If the drain plug is loose or the sealing washer is missing or worn it can cause an oil leak. This plug is located at the bottom portion of the engine oil pan. To check your oil drain plug gasket attach a wrench to oil drain plug and try to turn it counter clockwise. If the plug is tight but oil is still leaking the washer has failed and must be replaced. If the drain plug is loose and will not tighten the threads on the drain plug or inside the oil pan have failed and must be replaced or repaired to fix the problem.
Step 4 - The valve train inside the engine is covered by valve covers, these covers are sealed to the cylinder head with a valve cover gasket. When this gasket ages it can become brittle and crack allowing engine oil to leak out. Sometimes a valve cover can become loose over time. Fit a socket or wrench over the valve cover hold down nuts or bolts. Try to rotate the socket or wrench counter clockwise, it should be snug. If the mounting bolts or nuts are loose tighten and recheck. If the hold down bolts or nuts are tight and the valve cover is still leaking the gasket needs to be replaced.
Step 5 - This step is for V12, V10, V8 or V6 engines only, The intake manifold is mounted to the cylinders heads with a seal between the engine block and intake manifold. These seals are located at the front and rear of the intake manifold. Over time theses seals can age causing them to deteriorate and leak motor oil. Unfortunately there is no easy fix for this condition, the intake manifold must be removed and the seals replaced to repair this problem.
Step 6 - An engine is designed with a number of shaft seals depending on the type of engine it is. Atiming belt style of engine has more shaft seals than a non-timing belt engine such as cam and balance shafts. All engines have front and rear crankshaft seals. These seals are designed to ride against a turning shaft without allowing oil to pass through the seal. Engine heat can cause these seals to become brittle; as a result the rubber lip contained in the seal will fail allowing oil to exit the engine. Depending on the location of the seal, replacement procedures can vary from removing the transmission to disassembly of the engine front
Step 7 - Timing chain style engines have timing chain covers that are sealed to theengine block using a gasket. With time this gasket can become weak allowing engine oil to leak. If after inspection this is the case with your engine, the only remedy is to disassemble and remove the timing chain cover to replace the gasket.
Step 8 - Some engines are designed with an engine oil adapter that seals to the block with a gasket or "O" ring seal. This adapter is what the oil filter screws onto. Heat can cause the seal or gasket to fail, once a failure has occurred replacement of the seal or gasket is required.
Step 9 - Most engines are equipped with a distributor drive port where the distributor or sealing plug is mounted. If the "O" ring seal fails it will allow engine oil to leak out under pressure. If this is your engines oil leak the "O" ring seal must be replaced to repair the problem.
Step 10 - The engine oil pan is used to collect the engine oil into a centralized area so the engine oil pump can re-circulate it back into the engine. This pan is bolted to the bottom of the engine and uses a gasket to seal it to the engine block. If the oil pan gasket fails it can allow oil to leak from the engine. To repair this problem the oil pan must be removed and the gasket replaced.
Step 11 - Overhead cam designed engines have oil ports in the engine block that connect to the cylinder head. Oil is pumped under pressure into the cylinder head to lubricate the camshaft and other valve train components. If the head gasket on these engines fail it can cause this pressurized oil to leak out from between the engine block and cylinder head. If this is the case with your engine the head gasket must be replaced to repair the problem.
Note: Some engines are equipped with an external engine oil cooler that can leak. This engine oil cooler should be inspected when checking for an oil leak