The possible causes and remedies of the engine oil lubricating system

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Low oil pressure, internal and external oil leak, sounding valve, or connecting rod are some of the possible symptoms of an engine’s oil lubrication system error.

One does not need to be an automobile engineer to diagnose an engine’s lube system error.

I am here to point out some of the probable causes of oil lubricating system errors and how you can solve such issues on your own.

Point to be noted, if you have never worked with an engine or do not know the basics of engine troubleshooting, it is always a better option to do the job with the help of a professional.

Before we jump into the problem pointing and diagnosis section, here are some of the basics you might want to know about the engine lubrication system-

What is an engine lubricating system?

An internal combustion engine consists of multiple moving parts that create high friction and temperature when the engine is running.

An engine lubrication system lubes the moving parts of an engine to prevent scoring, burning, or any internal damage. 

The engine lubrication system includes a greasy and high viscosity fluid that runs through the moving parts of the engine to reduce the friction and temperature that those moving parts generate when the engine is running.

Read more: The Electric Fuel Injection system (EFI) system



The main engine’s oil lubrication system consists of several different organisms that work combinedly to keep the system running.

Here are the main parts of an engine’s lubrication system-

  • Lube oil samp tank (contains the oil for lubrication)
  • Strainer (removes larger particles)
  • Pump (transfers fluid from one location to another)
  • Cooler (cools the heated oil that comes out of the engine)
  • Filter (filtrates to prevent contaminants)
  • Heater (ensures better purification  by lowering the viscosity)
  • Purifier (removes  dirt and water)
  • Storage tank (stores lube oil)
  • Valves (controls the flow of fluid)

If the level of lube oil goes down in the Lube oil Samp tank, the open storage tank supplies oil to the samp tank by Gravity. 

When the level of lube oil in the samp tank comes to the right proportion, a sounding happens that closes the valve.

Therefore, lube oil stops transmitting from the open storage tank to the samp tank.

Possible engine oil lubricating system problems

Now that we have the basics of how an engine’s oil lubricating system works, let’s talk about the problems one may face with the lubricating system and how to diagnose those problems-

The top five symptoms of a main engine’s oil lubricating system error are-

  • Low oil pressure
  • Higher oil consumption
  • Sound from the main bearing
  • Sound from the connecting rod
  • Sound from the valve

Now, let’s find out the probable reasons behind those problems and the ways to solve the issues-

1. Low oil pressure

Probable reasons


Low oil level

Pour oil to the right level.

Faulty oil pressure sending unit or warning light

Requires new oil pressure sending unit or warning light installation

Diluted oil

Drain the loaded oil and refill the tank with the right graded oil.

Weak relief valve

Install a right-sized relief valve

Decayed oil pump

Replace the stock oil pump

Damaged or broken oil line

Replace the damaged oil line

Stucked oil filter

Change the oil filter

High bearing clearance

Repairing or measuring the appropriate bearing clearance

2. High oil consumption

If the engine’s oil lubricating system is consuming more oil than expected, this can be because of three probable reasons-

  • External oil leak
  • Internal oil leak
  • Oil leaks around the piston and piston ring

External oil leak

Probable  reasons


Damaged valve cover or fuel pump gasket

Replace the gasket

Lose timing gar cover

Change the gasket and tighten it according to the right torque level

Oil pump gasket or drain plug

Replacing the oil pump gasket or drain plug

Damaged oil seal of  front and rear main bearing

Change the oil seal

Oil line in the  oil filter gasket or filter

Replacing the gasket and repairing the oil line.

Closed crankcase outlet vent

Cleaning the vent

Internal oil leak

A faulty crankcase ventilation valve is one of the primary reasons why an internal oil leak may happen in the oil lubricating system.

Replacing or repairing the crankcase ventilation valve will solve the issue.

Oil leaks around the piston and piston ring

Probable reasons


Spotted, damaged, or broken piston ring

Replacing the damaged  oil ring and cleaning the oil ring deposits

Rotting outside the cylinder wall

Installing oversized piston

Cylinder block

Tightening the  head nut with the right torque level

3. Sound from the main bearing

Probable reasons


Insufficient oil supply

Check oil level. If necessary, change or replace the relief valve

Low oil pressure

Oil level checking

Diluted oil

Choose  oil according to the appropriate oil viscosity

Higher bearing clearance

Inspect the bearing clearance

Excess end-play in the crankshaft

Inspecting the rotting level of the main bearing and flange

Lose torque converter

Tightening to the right level

4. Sound from the connecting rod

Probable reasons


Insufficient oil supply

Checking  the oil  level and relief valve

Low oil pressure

Check oil level and other probable reasons

Diluted oil

Drain out the oil and pour the right viscosity oil inside the chamber

Higher bear clearance

Checking the bearing clearance level

Out of round connecting rod journal

Grounding the journals

Bended connecting rod

Replacing the connecting rod

5. Sound from the valve

Probable reasons


Low or high oil level

Adding or subtracting oil to the chamber until the oil level comes to the right level

Diluted oil

Adding the right viscosity oil

Low oil pressure

Checking oil level

Dirt in the valve tappets

Cleaning the valve  tappets

Bended push rod

Replacing the push rod

Decayed rocker arms

Replacing the faulty rocker arms

Decayed tappets

Installing new tappets

Decayed valve guide

Rimming the valve guides and installing new oversized stem valves

Higher runout in the valve phase and sit

Grounding the valve phase and sit

Preventing malfunction in the engine’s oil lubricating system

Modern engines are equipped in a way that allows the users to take long intervals between oil changes.

It is recommended that one changes the engine’s lube oil after every 5,000 miles.

Extended oil change intervals can be a good reason why one may notice malfunctions in the lubricating system.

At the same time, proper maintenance is more than important to prevent any issues with the lubricating system.

Those who maintain both the car and all the organisms related to the vehicle are expected to get a better service both from the engine and the vehicle.

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