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How Engine Sludge Forms. And How To Prevent It.

How Engine Sludge Forms. And How To Prevent It.

It’s ugly. It’s sludge.

Sludge.

It’s a disgusting phenomenon. Even the word sounds gross, like the thing it’s describing. The word for this is onomatopoeia, a strange word that many of us learned in high school English class. Splash. Grunt. Whoosh. Swish. Hiss. Frumpy. You know what I’m talking about.

What is sludge?

Sludge is a black gelatinous goo that renders equipment inoperable if not dealt with. And long before the engine’s demise, sludge can foul its sensors and interfere with performance. Some mechanics call it the “black death.”

How does motor oil, which is fluid, become a semi-solid paste or gel inside an engine?

How engine sludge forms

Essentially the formation of engine sludge is the result of a series of chemical reactions. The lubricant itself degrades as it is exposed to oxygen and elevated temperatures. The higher the temperature, the more rapid the rate of degradation. The by-products of this reaction form highly reactive compounds that further degrade the lubricant. Their by-products then react with other contaminants, forming organic acids and high-molecular-weight polymeric products. These products further react, forming the insoluble product known more commonly as sludge. What begins as a thin film of lacquer or varnish deposits on hot or cold metal surfaces eventually bakes into an expensive mess.

Synthetic base oils help prevent sludge

Fortunately, sludge and varnish deposits are something we oil manufacturers have a measure of control over. Using thermally stable base oils reduces the rate of initial degradation (oxidation). A good example of this is the use of common synthetic base oils such as API Group III, PAOs and Esters. Anti-oxidant additives help reduce the rate of degradation as well. One of the most widely used is zinc dithiophosphate. Not only is it an excellent oxidation inhibitor, it is an outstanding anti-wear additive as well.

So do high-quality additives

We can further address many of the issues occurring after the initial oxidation stage. Additive chemistry such as detergents and dispersants are commonly part of motor oil formulation. They help promote the suspension of contaminants within the oil and keep them from agglomerating. Detergents, which are also alkaline in nature, assist in neutralizing acids that are generated in the sludge-building process. Anti-oxidant, dispersant and detergent additives are consumed during use. To achieve maximum life expectancy, use an oil with high concentrations of these additives.

Severe service invites sludge

Good lubricants minimize sludge and varnish issues. How the equipment is used also has a bearing on the likelihood of sludge or varnish issues.

Stop-and-go driving, frequent/long-term idling and operation in excessively hot or cold weather can all increase the likelihood of sludge and varnish, especially if using more volatile conventional oils.

Interestingly, most auto manufactures note in their owner’s manual that operation under any of the above conditions is considered severe service and requires more frequent oil changes. From a mechanical standpoint, things like adding too much oil to the oil sump, antifreeze contamination, excessive soot loading, excessive oil foaming, poor engine combustion efficiency, excessive blow-by and emission-control-system issues can all lead to the formation of sludge and varnish.

By practicing good maintenance and using properly formulated, premium synthetic lubricants, like AMSOIL synthetic motor oil, your vehicle won’t succumb to the “black death.”

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Exploring Causes of Motor Oil Consumption

What Causes Motor Oil Consumption?

amsoil marketing ed newmanEd Newman|

 

Everyone who owns a vehicle knows you need to regularly check the oil level. (Note: If you do not know this, you’d better go check your oil. and Check your tires too!!

Sioux Falls drivers check often for signs of oil consumptionA certain amount of oil loss is normal due to motor oil volatility – that is, boil-off due to the high-heat conditions inside an engine. I once attended two days of training at a quick lube (part of a major oil company chain) wherein they showed how their conventional oil lost up to 30 percent of its weight and their synthetic only 12 percent in a volatility test. It drove home the message I’d already adopted that synthetics were more resistant to oil consumption than conventional oils. AMSOIL synthetic motor oils are even more resistant to volatility. (Read about AMSOIL performance in the NOACK Volatility Test.)

Volatility isn’t the only reason you need to replenish your oil supply now and then. The problem of abnormal oil usage is far more complicated and, in fact, most of the causes are mechanical, not lubricant-related at all.

One of the major causes is engine leaks. An AMSOIL technical service bulletin titled “The Reasons for Motor Oil Consumption” says:

Some of the many points where external oil leaks may occur include oil lines, crankcase drain plug, oil-pan gasket, valve-cover gaskets, oil-pump gasket, fuel-pump gasket, timing case cover and camshaft bearing seal. No possible source of leakage should be neglected because even a very small leak can cause extremely high oil consumption. For example, it has been estimated that a leak of one drop of oil every 20 feet is approximately equal to a loss of one quart of oil every 100 miles. One way to check for external leaks is to road test the vehicle with a large piece of light-colored cloth tied under the engine. Oil on the cloth will indicate a leak, which should be traced to its source.

I recently burned a lot of cash trying to get an oil leak fixed. The first task is accurately locating the source of the leak. The problem may be front or rear main bearing seals, worn or damaged main bearings, worn or damaged connecting rod bearings, worn or damaged camshaft bearings, worn crankshaft journals, distorted cylinders, worn ring grooves, cracked or broken ring lands, problems with the wrist pins, clogged oil passages or even unequal tightening of bolts.

Sometimes a defective cooling system can cause engine overheating, which may result in localized hot spots in some of the cylinders that can lead to scuffing and scoring of cylinders, pistons and rings, resulting in high oil consumption.

If you really want to sink your teeth into it, causes for oil consumption can include too much oil in the crankcase, worn or broken piston rings, improper valve timing, incorrect oil pressure, piston slap, an internal gasket intake breach, spark knock, aftermarket performance chips and modifications, lugging engines, inappropriate operation of overdrive, leaking turbocharger seals, a restricted air intake and fuel dilution.

In short, few things are as simple as they might initially appear. When all is said and done, however, even though there may be multiple reasons for oil loss, in a mechanically sound engine it boils down to one: oil volatility. In this matter, synthetic motor oil provides better resistance to oil consumption. If you have a mechanically sound engine, you should be using synthetic oil to reduce oil consumption and to protect your investment. In addition to reduced oil usage, synthetics can reduce emissions and improve fuel economy.

During my three decades of writing about oil, I’ve always recommended a synthetic solution.

Local note: From our Sioux Falls store staff we hope you enjoy Ed’s blog. We will be posting more from his decades in the industry. It’s our quest to serve and inform Sioux Falls drivers and auto enthusiasts to the highest degree and always provide products which not only out perform but solve problems just the same.