A vehicle needs oil to run and without it, or too little of it, severe damage can happen to the engine. Engine oil lubricates all of the major moving parts of the engine, which cuts down on wear and tear and dissipates the heat the engine generates. Not having enough oil in a vehicle can be deadly to the car’s engine.
Engine oil operates in a closed loop system so if the engine is losing oil at a significant rate, there is a problem somewhere, most likely a leak.
How this system works:
Engine oil is stored in the oil pan, which holds 4 to 6 quarts of oil depending on the vehicle. When the vehicle engine is started, the oil pump sucks oil from the oil pan through a part called the pickup tube. The oil is then pumped into the oil filter, which removes the dirt and debris that has accumulated in the oil. The engine oil then circulates throughout the engine via spurt holes before heading back to the oil pan where the process starts all over again.
Common reasons for this to happen:
Oil Light Comes On: The Low Oil Engine Warning light will illuminate when the oil level gets lower than it should in the oil pan. This warning light varies on vehicles but in most it looks like an oilcan with a droplet coming out of the spout. If this light illuminates for more than a couple of seconds at start-up the car should be inspected immediately as the oil level is too low in the car. This can lead to damage to critical engine components and expensive repairs.
Oil Leak: An oil leak can occur in just about any of the oil system components. Common problems are leaking or failing oil pan gaskets. As gaskets and seals age they tend to shrink and fail letting oil escape the system. A leaking gasket can quickly turn into an expensive repair if not addressed, as critical components will not have the lubrication they need to operate safely.
Worn Piston Rings: Piston rings help control the oil pressure in the vehicle. If they are worn or damaged the oil levels in the car will drop. Look for white or gray exhaust smoke, slow acceleration and excessive oil consumption. This problem can quickly damage critical and expensive engine components such as the pistons themselves and should be repaired quickly.
Faulty Worn Valve Guides: Valve guides are a cylindrical piece of metal that is pressed or cast into the cylinder head. They help to conduct heat away from the combustion process and into the cylinder head where it may be taken up by the cooling system. If valve guide seals are worn, cracked or broken the engine will suck oil down the guides and dump it into the cylinder, which will pull oil from the lubrication system. Oil levels will drop. This problem should be addressed as soon as possible.
Incorrect Oil Type: Engines can be filled with low viscosity synthetic oil, which reduces friction and increase fuel efficiency. A lower viscosity oil is thinner and can leak past rings and the seals on valve guides resulting in a loss of oil. Synthetic oil should not be used for the engine break-in period.
Assembly Mistakes: Piston rings that are not seated or sealed properly can cause oil to leak out of the engine. This problem can result in significant oil loss. The engine must be rebuilt to correct this problem.
What to expect:
Oil will become black and a bit gritty over time, this is normal and does not indicate that the oil needs to be changed. Most modern oils, especially the synthetics can last between 7,000 and 10,000 miles before they need to be changed.
How it's done:
A mechanic will inspect your car for oil leaks, the oil type and check to see if the oil level warning light is operating as it should. The mechanic will also inspect some related engine components. This will include valve guides, piston rings and more.
How important is this service?
Loss of engine oil is almost always a sign of a more serious problem. Engine oil is literally the lifeblood of the car and if the levels get too low it can damage critical components of the engine. Oil loss or high oil consumption should be investigated as soon as possible.