Oil Pan Explained | Function, Parts & Common Problems | Car Engine Basics.

1. What is an Oil Pan?

•      The oil pan is a metal container placed at the bottom of the engine.

•      It stores the engine oil that lubricates all moving parts inside the engine.

•      Think of it as the oil storage tank of the engine.

•      It is also called the Sump.

2. Location of Oil Pan

•       Fitted at the lowest part of the engine (under the crankcase).

•       Bolted with oil pan bolts and sealed with an oil pan gasket.

•       Easily visible from under the car.

3. Purpose / Function of Oil Pan

     A. Stores Engine Oil

          Main function - Holds the required amount of oil (usually 3–6 liters, depending on engine size).

     B. Collects Returning Oil

        After oil lubricates engine parts (pistons, crankshaft, camshaft, bearings), it drains back into the oil pan due to gravity.

    C. Helps in Cooling the Oil

       *The oil pan is made of aluminum or steel.

       *Airflow under the car removes heat from the oil pan.

       *Some oil pans have cooling fins to improve heat dissipation.

    D. Allows Oil Circulation

      *The oil pump sucks oil from the pan through a strainer.

      *Then oil is circulated to all engine parts.

      *Oil returns back to the pan → cycle repeats.

   E. Provides a Place for Drain Plug

     *The oil drain plug is fitted at the bottom of the pan.

     *Used during engine oil changes.

4. Construction of Oil Pan

    Oil pans are made from:

    (1) Stamped Steel

•              Strong and affordable.

•              Mostly used in passenger cars.

(2) Cast Aluminum

• • Lightweight, better cooling.

  • Used in modern engines.

5. Shape

   Deep enough to store oil.

   Designed to prevent oil movement during braking/turning.

6. Parts of Oil Pan

•     Oil pan body

•     Oil drain plug

•    Oil pan gasket

•    Cooling fins (sometimes)

•    Baffles (internal walls)

7. What are Baffles?

        Inside the oil pan, baffles are small metal plates that control oil movement.

8. Why are baffles needed?

• When the car:

• brakes suddenly,

• accelerates quickly,

• climbs hills,

• takes sharp turns, the oil may shift to one side.

• Baffles keep the oil steady near the oil pump pickup so the engine always gets an oil supply.

9. Working Principle of Oil Pan

• Here is the simple oil flow cycle:

• Oil is stored in the oil pan.

• Oil pump sucks oil through the strainer.

• Oil goes through oil filter → then circulated to engine parts.

• Oil lubricates and cools the engine.

• Used oil returns back to the oil pan.

• Cycle repeats continuously whenever the engine runs.

10. Symptoms of a Bad Oil Pan

A. Oil Leaks Under the Car

Most common symptom.

B. Low Engine Oil Level Warning

Leak reduces oil quantity.

C. Burning Oil Smell

Oil drops on exhaust pipe.

D. Engine Overheating

Not enough oil for cooling and lubrication.

E. Visible Damage

Dents or cracks if the car hits a stone or speed bump.

11. Causes of Oil Pan Problems

• Hitting speed breakers or road debris.

• Worn or damaged gasket.

• Over-tightening the drain plug (threads get damaged).

• Rust or corrosion on old vehicles.

• Loose oil pan bolts.

12. Oil Pan Leak Symptoms

• Oil droplets under the engine.

• Wet or oily oil-pan surface.

• Engine oil level drops quickly.

• Burning smell during driving.

• WARNING light on instrument cluster.

13. Oil Pan Designs and Types

(A) Wet Sump Oil Pan

• Most common type.

• Oil is stored in the oil pan itself.

• Simple and inexpensive.

(B) Dry Sump Oil System

• Used in race cars and sports cars.

• Oil is stored in an external tank.

• Allows better lubrication and no oil starvation.

14. Advantages of Oil Pan

• Simple oil storage solution.

• Helps cool the engine oil.

• Easy maintenance (oil change).

• Reduces engine noise.

15. Maintenance of Oil Pan

• Regularly check for oil leaks.

• Replace gasket during servicing if required.

• Do not over-tighten the drain plug.

• Inspect for cracks or dents.

• Use correct grade engine oil.

16. Oil Pan Leak Repair

• Replace the damaged gasket.

• Use proper torque for bolts.

• If pan is damaged → repair or replace.

• Fix stripped drain plug threads using: Helicoil insert, or Oversize drain plug.

Simple Summary

👉 Oil pan = Engine's oil storage tank

👉 Stores oil, cools oil, and returns oil for recirculation

👉 Fitted at bottom of engine

👉 Problems: leaks, cracks, gasket damage

👉 Must be checked regularly to protect engine