Engine Sludge – The top 2 ways, to stop or slow down, Engine oil sludge.

Engine Sludge - The top 2 ways, to stop or slow down, Engine oil sludge.
Engine Sludge - The top 2 ways, to stop or slow down, Engine oil sludge.

Engine sludge, forms as engine oil oxidizes and breaks down; leaving behind deposits recognized as, engine sludge.

Engine oils break down, during oxidation and combines with dirt, fuel, metallic particles, water, gases, and coolant.

So, as the lubricating properties are diminished, they are less able to clean the engine.

When engine sludge is present, oil is not able to properly lubricate, the moving parts of your vehicle’s engine.

Because, at some point additives and detergents, will evaporate, lose potency and disappear. So, engine sludge often results from, poor maintenance and low grade oils. Consequently, a good engine oil, will keep all of these harmful contaminants suspended in the oil. So, they can be flushed out, on your next oil change. But, some engines appear to be, more prone to sludge buildup than others.

Certain Engines Are More Susceptible To Sludge Than Others

Engine Sludge In 4.7 Chrysler Engine
Engine Sludge In 4.7 Chrysler Engine

Just because you carefully follow the manufacturer’s instructions, doesn’t mean engine sludge build up won’t happen.

But, some engine manufactures, appear to be more prone to sludge buildup than others:

  • Chrysler
  • Toyota
  • Volkswagen

Take note of recalls and service bulletins, related to your car and have all repairs handled immediately. Engine sludge prone engines, should change the oil according to the “extreme use” schedule in the owner’s manual.

Know The Warning Signs:

  • Low oil pressure or intermittent flashing of the oil light.
  • The oil light remaining on, when the engine is running.
  • Slow or no draining of the oil, when oil plug is removed.  (sludge is preventing the remaining oil from draining)
  • Obvious signs of thick sludge in oil fillers, rocker covers etc.
  • The engine won’t accept, the designated amount of oil after an oil change.  (sludge is taking up some, or most, of the oil space)
  • Noisy hydraulic lifters. (where fitted)

Top 2 Ways To Stop Or Slow Down, Engine Sludge:

Proper Engine Maintenance

Proper Engine Maintenance Is Important
Proper Engine Maintenance Is Important

Engine sludge, is very common and also a very costly problem. Proper maintenance, is the most important key to the prevention of engine sludge. The development of engine sludge, is directly related to, how often you change your oil. Manufacturers market their oils with specific additives, to customize their products, for different types of engines.

As a result, these oil additives include, conditioners that lubricate the seals to prevent leaks. Detergents are there primarily, to prevent deposits. They’ll also inhibit rust and corrosion, inside your car’s engine. Also, helping dissolve existing buildup, before it becomes a problem.

Crankcase Ventilation System – (PCV) Valve

So, engine sludge can be caused by, a poorly designed or defective, crankcase ventilation system. If the (PCV) system fails, severe sludge buildup and oil leaks can occur. The (PCV) system, helps remove moisture, a major contaminant, from the oil. When an engine is running, it generates a good deal of heat. When the engine cools, condensation forms.

Engine oil additives, absorb this moisture and hold it in suspension. In time the moisture content, exceeds the capacity of the additives. When this occurs, moisture attacks the metal parts of the engine causing damage.

A sign of moisture contamination is, a cloudy or milky film in the (PCV) valve or hose. Finding water in the (PCV) valve, suggests a need for replacement. But, is also an indication of other problems.

High Moisture Content In (PCV) Hose
High Moisture Content In (PCV) Hose

Replacing the (PCV) valve, gets rid of the symptom. But, the problem remains and symptoms, will soon return. High moisture content means, we need more frequent oil changes and longer drive cycles. A moisture buildup with normal driving, shows other engine problems. Several areas of an engine, can allow leakage and oil contamination. Resulting in, engine sludge.

Coolant And Fuel Leaking Into The Oil Is Very Serious

Moisture Contamination
Moisture Contamination

Moisture contamination, flows through the engine oil filter, as it is a liquid. This is one reason why, oil must be changed. Short trips make the problem far worse, as the engine does not reach, full temperature. Oil should be replaced more often, when average driving distance, is under ten-miles. As the engine reaches full operating temperature, the heat of the oil, causes the moisture to boil. If the vehicle is driven far enough, the (PCV) system will scavenge much of this moisture from the oil.

So, this is one reason vehicles can go further between oil changes, when the average trip is very long.  While, with short trips, this does not occur, requiring more frequent oil changes.

The type of driving determines, oil change needs. And, is a better guide, than just the number of miles driven.


So, it’s no coincidence that, one of the most overlooked engine problems; is also responsible for, the most costly repairs. That’s why, overlooking engine sludge, is a decision, that most people will regret. Therefore, searching for the signs of engine sludge; changing your oil regularly and reading your car’s manual, will help keep you down the road. Finally, a little planning and effort now, can save you a lot of trouble in the future.

Thank You !