Do you really know the functional components in the engine lubricating system in automobiles, is the oil pan or sump included? An oil pan is a metal dish that covers the bottom of the engine block. It serves as a reservoir that keeps the engine oil which from its oil circulates around the engine. There is a pickup tube from an oil pump that enters the sump and sucks up the oil. Today we’ll be looking at the definition, functions, working, types, parts, and symptoms of a bad oil pan.

engine oil pan or sump


What is an oil pan or sump?

An oil pan is a shaped stainless metal that covers an engine beneath and keeps lubricating oil when the engine not running. For the sump to perform its full function, it’s shaped into a deeper section, and the sump is mounted at the bottom of the crankcase serving as oil storage/reservoir. Apart from the major function of an oil sump, which is storing the engine oil. It also serves the following purposes:

Functional parts of an oil pan/sump

Below are the major parts of an oil sump in an automobile:


due to the vibration of most engines, oil in the pan slosh around as the vehicle accelerates and corners. This causes the oil to move away from the pickup pipe, preventing the oil to flow properly through the engine.

This is a bad situation that could starve the engine with oil, to avoid this, baffles are featured in the oil sump to prevent the oil from moving around. Though they can take various forms, their function is to stop the flow of a huge body of liquid, keeping them ready to be socked.


As earlier mentioned, dipsticks are used in an internal combustion engine to gauge the amount of oil in the engine. The gauging is achieved by dipping the stick down into the oil pan which shows the level of oil when removed.

An electronic sensor is used on modern engines to determine the level of oil on a dashboard indicator.

Windage Tray:

The windage tray is a piece of metal sheet that prevents oil from splashing up onto the spinning crankshaft. it also has some form of crankshaft scraper which removes excess oil clinging to the crankshaft counterweights.

Drain Plug:

A drain plug is located on the body of the sump. It is a traded bolt that allows dirty oil to drain out of the oil sump. It features a washer which should be replaced whenever the plug is removed. Oil is easily removed when warm.

Working of Oil Pan

The working of the oil pan in the engine lubrication system. The lubricating oil is poured from the top of the engine which flows from the camshaft to other moving components of the engine to the sump. The sump stores the oil when the engine stops working and the oil pump begins to suck the oil immediately after it starts running.

The oil sump is designed to keep the oil in place so as to prevent the oil from sloshing around. When the vehicle is moving, there is airflow under the sump that cools the hot oil preparing them for lubrication. Though some sump features a cooling fin which increases its surface area.

After some time, the oil will be dirty and needs to change. At the bottom of the pan, there is a drain plug that will be open to allow the old oil to flow out. The plug will be screwed back after the oil is drained. Some drain plugs are designed with a magnet that holds metal fragments from the oil and some contain replaceable washers to prevent leakage. Leakage is often caused by corrosion or worn threads in the drain hole.

Watch the video below to understand the working of oil sump better:

Types of Oil Sump

Below are the two types of oil sump used in an engine:

Wet sump system: the wet sump system is the most common and standard oil sump in the automobile engine. it is called a wet sump because the sump carries oil serving as an oil reservoir. It uses a single oil pump to transfer oil through the galleries.

Dry sump system: the dry sump has an extra oil reservoir outside the engine rather than the oil pan. Oil is pumped out of the sump to a remote container. It works with at least two oil pumps, one sucks oil from the sump and sends it to the external tank. From the external tank, the second pump transfers the oil to lubricate the engine.

For better oil circulate in an engine, the oil pan must be in good condition but the question is how will you know if an oil pan is faulty? This article will give you an understanding of that.

Puddles of oil under the car: If you noticed puddles of oil under your engine, it is a sign that your oil pan is having issues and needs to be replaced. Oil sump that puddles will cause the oil to leak and if not fixed it gets worse as time goes on.

Visible damage to the oil pan: The visible damage is a sign or dent on the oil pan obtain from a bad road or area. The oil pan is the lower component in an engine so it easily comes in contact with the ground. Bad roads cause damage to the oil pan. If you see a crack in your oil sump, consider changing it to avoid the worst problem.

Oil leakage around the drain plug: The drain plug is the spot where old oil is discharged during an oil change. it is always locked to prevent oil from leaking. When the drain plug gets damaged, it may begin to leak oil. In some situations, the drain plug gasket might need to be replaced to stop the leaking which is a minor problem. However, if the threaded drain plug gets damaged, replacement should be done as soon as possible.

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That’s it for this oil sump/pan article. I hope you enjoyed the reading, if so, kindly comment, share, and recommend this site to other technical students. Thanks!

2 Responses

  1. Very informative post! I had no idea there were different types of oil pans/sumps or that they played such a crucial role in the functioning of a vehicle. Thanks for breaking down the components and how they work together. Looking forward to learning more from your blog!

  2. Thanks for providing such a detailed explanation of oil pan/sump! I never realized how important it is in keeping our engines running smoothly. The different types and parts of the oil pan/sump were explained clearly and concisely. The working of the oil pan/sump was also well-explained, and I appreciated the information on common problems and their solutions. Great post!

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