Which Engine Component Stores Oil For Lubrication? The Truth

Engine oil allows your vehicle’s engine to run efficiently by lubricating components and preventing excess friction and wear. This vital oil has to be stored somewhere when it’s not circulating—enter the oil pan. As the reservoir that supplies the lubrication system, proper functioning of the oil pan is critical.

This article will dive deeper into oil pan design, location, maintenance, and what happens if this key engine component should fail.

Oil plays a critical role in your engine’s lubrication system, keeping your vehicle running efficiently. It coats all moving parts in your engine, decreasing friction and wear while drawing heat away from those lubricated areas.

Your engine requires various components to get the oil it needs for lubricating its moving parts. These include a filter, pressure relief valve, pickup tube and oil pump.

Key Points

  • Oil Pan Purpose and Function
  • Where is the Oil Pan Located?
  • Oil Circulation Pathway in Detail
  • Oil Pan Capacity and Construction
  • Consequences of Oil Pan Failure
  • Inspecting and Maintaining the Oil Pan
  • Options for Replacing Oil Pans
  • Other Engine Oil Storage Components

Which Engine Component Stores Oil For Lubrication?

The engine lubrication system works by injecting oil into various parts of your car’s engine. This reduces friction between moving parts, helping keep everything running efficiently.

Lubricating also cools the oil, drawing heat away from lubricated components and preventing your vehicle from overheating. This is essential as it extends engine life by reducing wear-and-tear on its components.

Lubrication systems can range in complexity, but the most essential part is the oil pan. This is exactly where you store the lubricating oil that your vehicle uses to lubricate engine components like crankshaft & camshaft bearings as well as valve lifters.

Which Engine Component Stores Oil For Lubrication

Check: Engine Oil Won’t Drain

Engine Lubrication System: Main Components

Oil provides lubrication to engine components, decreasing friction and wear. It also transports heat away from these parts, extending their lifespan.

Engine lubrication systems consist of several key elements, including an oil pump, pump reservoir, metering device, controller, filter and supply lines. Let’s not forget that small-scale and manual lubrication methods like chain oilers or grease guns may be employed as well.

Modern lubrication systems use an engine-driven pump to deliver oil from the oil pan and push it upward through a duct in the engine block, then pass it through a filter outside the block. Afterward, this oil is directed either to one main gallery or two main oil galleries running along the length of the crankcase at about the level of cylinder bore bottoms.

How Does a Lubrication System Work?

Engines, machinery and equipment of all kinds rely on lubrication to reduce friction between moving parts. This includes pistons, pumps, cams, bearings, turbines and motors.

Oil is often employed to lubricate these machines, decreasing friction between parts and thus increasing their lifespan.

It is safe to say that there are various lubrication systems in use. Some require more complex components and require specialized pumps or motors for optimal operation.

The most typical lubrication system utilizes a reservoir to store oil for use as lubrication. This oil is then pumped through the system to deliver it to machine parts that require it, then filtered and returned back into the reservoir for reuse.

Why the Need for an Oil Reservoir?

Before jumping specifically into oil pan function, let’s stepping back and review why engine oil needs to be stored in the first place:

High Temperatures Reduce Oil Volume – As oil circulates and absorbs heat it expands in volume. Some oil is also lost due to evaporation and burning off. This reduced volume needs to be replenished.

Extended Operation Requires Extra Supply – An engine may run for hours or days between being switched off. This requires extra fresh oil beyond what is actively circulating.

Efficient Lubrication Needs Continuous Oil Supply – A break in the supply of pressurized, filtered oil would immediately stop lubrication of vital components leading to failure.

Reliable Startup Requires Oil Pre-Load – With the oil already pooled in the pan, the lubrication circuit can spring to life immediately as the oil pump activates.

Without an oil reservoir, engines would suffer oil starvation with no contingency for volume loss, lengthy operation times, continuity of supply or smooth startups. That’s where the ingenuity of the oil pan comes in!

Mounted Underneath the Engine

The oil pan bolts onto the bottom of the engine block covering the lower crankcase area. It is positioned below moving components like the crankshaft, connecting rods and pistons.

This offers three key advantages:

  • Gravity causes used oil to naturally drain back down into the pan as engine parts move.
  • The pan is sheltered by the bulk of the engine from debris, impacts, and extremes of heat or cold.
  • Air flow under the vehicle assists with dispersion of heat from hot oil collecting in the reservoir.

Oil pickup tubes descent into the oil pan sump – the lowest area where oil pools. This ensures constant access to oil even when cornering forces the oil to one side. On high performance cars, baffles may be incorporated to prevent oil starvation.

The Detailed Journey of Engine Oil

Let’s trace the specific route oil takes from the pan during operation:

  1. Oil pump – The gears or rotors of the oil pump pull oil in through the pickup tube and pressurize it up to 60 psi depending on engine speed and load.
  2. Oil filter – Before reaching critical components, pressurized oil runs through a paper or magnetic cartridge that traps contaminates.
  3. Main oil gallery – Oil first reaches the main bearings in the engine block itself. Grooves then route it to smaller passages.
  4. Cam bearings – Through drilled channels inside the block, oil makes its way up to lubricate the camshaft and valve train. Leaking valve cover gaskets can contaminate oil in this area.
  5. Crankshaft – Oil squirters, sprays and slotted main bearings direct high-velocity oil to the crank pins, connecting rod bearings and piston skirts. This is the highest pressure area to overcome intense friction forces.
  6. Timing chains – The timing chain at the front of the engine has an oil jet targeting its tensioner and gears on some vehicles.
  7. Return to oil pan – After absorbing heat and contaminants, used oil falls back down into the oil pan through openings to await recirculation.

This closed loop system allows continuous flow of pressurized oil to lubricate all the vital moving parts!

Construction of Oil Pans

Oil pans come in a variety of shapes and sizes depending on engine configuration and vehicle application:


  • Stamped steel sheet – Most common, inexpensive but prone to dents. Zinc or aluminum coating prevents rust.
  • Aluminum casting – High-performance vehicles, better heat dissipation but costlier.
  • Plastic – Rare, mainly older vehicles. Prone to cracking.


  • Shallow pan – Basic engine applications with lower oil capacity
  • Deep sump – High performance cars hold extra quarts of oil
  • Irregular shapes – Custom shapes to fit around exhaust or suspension components


  • Extra baffles – Prevent oil flow away from pickup during acceleration
  • Windage trays – Help maintain oil supply to pickup with high crankshaft speeds
  • Drain plugs – Allow easier oil changes
  • Scraper rings – Remove oil clinging to rotating crankshaft

Oil pan bolts torque down to specificity tightness levels during manufacturing. Even gaps allow reliable sealing without leaks.

What Happens With Oil Pan Failure?

Given its importance, problems with the oil pan leaking or becoming damaged require immediate attention. Consequences include:

External Leaks

  • Low oil levels – Oil dripping externally means less gets recirculated
  • Environmental damage from leaks – Oil leaks are hazardous ecological contaminants
  • Low oil pressure – External leaks directly always reduce internal oil supply leading to lubrication issues

Internal Leaks

  • Oil starvation – Cracks or blockages in pickup tubes prevent oil supply to the pump and lubrication system
  • Oil aeration – Air ingestion causes oil pump cavitation ruining oil pressure
  • Engine overheating – Cooling capabilities decline as less oil circulates

General Wear and Contamination

  • Sludge buildup – Oxidation and blowby contaminants accumulate reducing oil capacity
  • Rust corrosion – Humidity seeping in causes pan corrosion and rust particles in oil
  • Diminished cooling – Dents or damage reduces air flow efficiency to cool hot collected oil

Ignoring oil pan problems inevitably leads to lubrication failure and catastrophic engine damage. Immediate oil pan repair or replacement is essential.

Protecting Your Oil Pan

Here are key ways to ensure your oil pan and lubrication system stays healthy:

  • Regular oil changes – Flush out contaminates and top off fresh additives
  • Use proper oil weights – Choose viscosity rating suited to your operating climate
  • Inspect at oil changes – Look under car for any signs of leaks
  • Prompt gasket repairs – Fix external leaks right away before it worsens
  • Install undertray guards – Shield oil pan from debris which could puncture
  • Careful driving – Avoid scraping steep inclines or curbs which could dent pan
  • Replace pan every 60-100K miles – Prevent fatigue cracks as it ages
  • Consider premium pans – Higher strength aftermarket pans resist damage

With attentive inspection and maintenance, your oil pan can supply continuous lubrication for engine longevity.

More Engine Oil Reservoirs

Beyond the main oil pan holding the majority of supply, some engines also incorporate additional integral oil reservoirs:

  • Oil filter housing – Center cartridge filters hold a usable pint of reserve oil if needed
  • Lifter valley – Shelves on cylinder block hold pools of oil feeding valve train components
  • Timing cover – Some covers feature extra internal oil supply for cam gears
  • Oil control rings – These piston ring grooves hold oil as they travel up and down in cylinders

So in some engines, supplemental reservoirs augment the main oil pan supply. But the oil pan remains the starter motor that kicks the entire pressurized lubrication system into action!

Common Problems with Oil Storage Pan

The engine oil pan is a reservoir where oil is pumped from the bottom of the engine to lubricate and clean moving parts. It also stores excess oil until it can be drained with a drain plug.

The oil pan is usually constructed of metal and holds between four to six quarts of oil, depending on the model. It attaches to the bottom of the engine using bolts.

Damage to an oil pan can result in leaks and puddles of oil under your vehicle. Usually, this is indicative that it’s time for you to replace the pan.

It might even be a case where you’ve notice oil leakage around the drain plug. If this is the case then you have an issue that needs a to resolve. So, if you find the drain plug leaking oil, the drain plug gasket or the plug is faulty, then you will need to get the faulty component fix.


One thing for sure is that at some point leaks happen. The good news is that you can always do something in regards to fixing the leak if you know where the oil is leaking from. Taking the time out to know about the parts of an oil lubrication system will help you out.