Understanding lube oil and its job functions:

   There are several jobs that the lube oil is designed to perform. Function of Lubrication is to keep parts moving apart, cooling, cleaning, corrosion control, Carry away contaminants & debris, transmit power, seal gases,.... etc. The oil companies work diligently to produce oils to meet engine manufacture's ever increasing requirements, creating better and better oils each year.  Over the years, using  vastly improved oils, the engine manufacture's have increased their recommended oil drain intervals for their engines, but we are still draining the oil on a routine basis. When most maintenance personnel are asked, "why does one have to change the oil?" Their answer is usually one of the following: "Because it breaks down" or " Because it wears out."

    The concept that oil "breaks down" or "wears out" is not correct. Just look at what has happened over the past fifteen years, in regards to oil drain intervals. 40 years ago, typical recommended oil drain intervals was around 5,000 to 7,000 Km.  Today, the oil drain intervals have increased to 10,000 to 15,000 Km.  The same quality crude oil base stocks that were used 40 years ago are used to make oils of today.  So why does the same oil today last twice as long as it did fifteen years ago?  The answer can be found within the additive package & modification of today's oil.  The petroleum base of oil lube does not wear out, rather it is the additives within the oil that become depleted, due to the presence of contamination. Contamination arises from Oxidation, Nitration, Acid formation, water and ....etc. In lay man language, The Engine is your body and the engine oil is your blood which circulate and carries the minerals & oxygen to every parts of your organs and also carries away the waste to your kidney for filtration. Just like engine oil it does the same purpose of what your blood does, carrying the clean oil to all the moving parts and carries away the dirty oil to the oil filter from filtration. Dirty oil leads to disaster just like in human where we have heart attack, kidney & liver failure.

   Typically lubricants contain 90% base oil (most often petroleum fractions, called mineral oils and less than 10% additives. Vegetable oils or synthetic liquids such as hydrogenated polyolefin, esters, silicones, fluorocarbons and many others are sometimes used as base oils. Additives deliver reduced friction and wear, increased viscosity, improved viscosity index, resistance to corrosion and oxidation, aging or contamination, etc.
What is Oil Sludge

The term engine sludge, also known as black sludge, describes the formation of heavy deposits in the crankcase of petrol engines. Its formation sludge can usually be traced to inadequate servicing, such as missed or extended oil change intervals or to the use of poor quality or inappropriate oils which can stick onto any parts of the engine, transmission gear box or differential gear in the axle.

Sludge can resemble heavy grease or tar and results from the thickening and oxidation of the engine oil. The resulting material blocks the engines lubricating system, causing the engine to seize. I used to called it the Bad Engine Cholesterol for the all vehicle. Just like in human beings the bad (LDL) cholesterol will stick/deposited onto our artery, vein and narrowed or even worse causes total blockage of the artery & any blood vessel  choking off human heart our blood supply to all parts of our body. Just like in cars, sludge have the same function as of human's LDL, choking off oil supply to various moving/rotating parts of the car like main journal bearings, piston liner, tappet, camshaft bearing, transmission bearings ....etc. In human, we can use Angioplasty "stents or Balloon" to expand the blockage, but on cars we are unable to use Angioplasty, reason is all oil passages are either made of cast iron, aluminum alloy or steel.  

Once the engine had sludge, it will be expensive in removing them totally. As some may say that by adding oil flush chemical into the engine oil before changing of the engine oil, will flush out the sludge but to what extend? Ask your self when you had a badsludge choke toilet bowl or washing basin drainage system choke with harden oil stuff. What will you do? Pour in hot boiling water to melt away the harden oil? or get a professional to manually clear out any choke?  Chemical flusher sold in the market world wide in all kinds of brand and trade marks, do help to remove certain amount of sludge. The best method for removing these sludge is to manually strip down/dismantle the engine, transmission or differential units and cleaning it with sludge removal, manually using equipments like brushed scraper & etc on the engine components together with sludge removal chemicals. 

Engine sludge deposits are most commonly found in petrol engine,sludge although sludge can accumulate in diesel engines too through a slightly different process.

To prevent the formation of sludge problem in your engine my personal advice is to use the correct type & grade of lube oil and have a regular interval oil change of the engine with a knowledgeable car technician.

How Sludge are formed

Sludge are formed when lubricant is prolong heated, oxidation due to poor or bad EGR , PVC of the engine and low mileage usage, lack of interval oil change, deterioration of the oil additives, water/coolant contamination, air filter, high temperature of the engine it could reached to 120ºC. The oil gets overheated and burned turning black in color, contamination arises from oxidation, Nitration, acid formation, water as air contain water moisture, sooth, dust blow-by gas...etc. Inferior/poor quality of engine oil do also causes formation of sludge due to lack of additives that are required to be added into the engine lube oil during refinery processing. Wrong grade of engine lube oil are also one of the factors and that is where the API (American Petroleum Institute) comes into the picture with the "donut sign" printed on every bottled lube oil.

An example of how sludge formed is just like whatprolong used eddible oil your see in deep fried pisang goreng's or French fried picture on your left.  Where you will find the oil used for deep frying looks brownies/black in color and if you will to scope up the below oil pot, you will find the some thick black burn sludge. It looks like your engine oil after certain mileage of usage isn't it? Why? these are mainly due to water contamination, high temperature/over heated of the oil, dirt...etc

Using mineral oil are more prone to oil sludge, as mineral oil contain hydrocarbon and wax.

Each type of oil have different working temperatures. Therefore it is very important, when you choose your engine lube oil........Types of Engine lube oil

What will happen to my car when it have sludge?

Firstly, it will restrict the engine oil flow to all the moving parts like your main journal bearing, piston rings, and cylinder walls, tappet, camshaft bearings....etc in side your engine and your car will looses power.

Secondly, severe sludge will cause your engine to seize (just like in human beings, the patient will have a heart attack when blood there is no supplied  and these happen when there is too little or totally no lubricant been supply to the moving parts.

Thirdly, the engine or any moving parts  will have heavy/serious shear & wear and tear and the engine will becomes nosier, poor respond when you need power during acceleration (loss of power).  

sludge sludge sludge chocking the oil filter
heavy sludge on the bottom of oil pan sludge on timing chain oil sludge
sludge engine oil sludge sludge
Daniel the expertise in cars and automotives trade
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