After prolonged exposure to high heat, engine oil can oxidise and break down, forming deposits known as sludge. This gelatinous substance can block vital oil passages, resulting in total engine failure or very expensive repairs.
The black death ‘health’ pandemic resulted in the deaths of an estimated 75 to 200 million people in the years 1346–53! The ‘Black Death’ being referred to here is the name that has been given to the oil sludge epidemic that ruined thousands of engines worldwide in the 1980s. Unfortunately, it has made a comeback!
Black sludge build-up is usually caused by poorly designed or defective crankcase ventilation systems, low engine operating temperature, faulty injector seals or the presence of water in the engine oil. Lack of maintenance, in particular, engine oil changes or using incorrect engine oil in your vehicle can contribute to this issue.
How engine oils work
Engine oil can be either conventional or synthetic. It works to absorb and protect your engine from contaminants. Over time, however, it reaches its capacity of absorption and instead of carrying away contaminants, deposits them on the engine surfaces and in all the other parts where it circulates. Instead of lubricating and reducing friction, the oxidised sludge causes a buildup of heat in the engine. Engine oil functions as a coolant to some extent, but oxidised sludge acts as the opposite. You’ll notice that the oil pressure is either dropping if your vehicle is equipped with a pressure gauge or engine oil indicator flashing and staying on, and you get increased fuel consumption and engine temperature.
Engine oil sludge first develops on the top of the engine, the valve cover section, and in the oil pan of the sump. Next, it blocks the oil strainer siphon and stops oil from circulating in the engine leading to more damage with every stroke. Aside from severe engine damage, you also risk damaging the gaskets, timing belt, radiator and cooling systems of the car.
Can engine sludge be removed?
Yes. The proper detergents in the correct concentration can dissolve engine sludge and deposit. Ideally, sludge won’t form at all; however, sometimes mechanical issues arise, such as a leaking head gasket, and the formation of sludge occurs. If sludge does form, the oil’s detergents help dissolve and disperse sludge to clean the engine.
This is more challenging than it sounds. For starters, the oil must perform several functions, not just help prevent engine sludge. For that reason, oils contain a limited concentration of detergents (compared to an engine flush product) to ensure room in the formulation for other additives that protect against wear, fight oxidation, combat rust and more.
Is an engine flush necessary?
A good engine flush product can help loosen deposits and dissolve sludge, returning your engine to like-new condition. However, in old engines with high mileage, sludge may be the only barrier keeping oil from seeping through worn seals. Removing the sludge exposes the seals for what they really are. Soon, your engine begins leaking oil or smoking, and your mind instantly associates the engine flush it
In reality, the seals were already bad; the flush simply revealed their true condition.
If you suspect your vehicle falls into this camp, leave well enough alone and skip the engine flush. It’s probably not worth trying to revive an engine in such poor condition without first fixing the bad seals or other defects.
In effect, you’re choosing your problem: either sludge and deposits robbing performance or if you clean the engine, the seals showing their true condition.
Noticing the warning signs can work wonders to optimise the health of your car, but taking preventive steps is the best path for everyone. If you have not yet done so, take a look at your vehicle’s manual to determine how often you should change the oil. When living in a city like Lagos, where traffic jams are a daily occurrence, people often stop and accelerate at several intervals before reaching their destination. Repeatedly stopping and accelerating hastens the process of oxidation in your engine.
Servicing the engine regularly, using the best available synthetic engine oil, is one major step to preventing engine sludge build-up
It’s no coincidence that one of the most overlooked engine problems is also responsible for the most costly repairs. For your car to function, many parts need to work together in harmony, and if anything falls out of place, the whole system becomes unbalanced. Overlooking engine sludge is a decision that most people will regret.