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Engine Sludge Recognition and Prevention Tips

Oil Dipstick

Engine repairs are one of the most expensive costs associated with cars. If the engine, transmission or body is shot, those repairs can easily overwhelm your budget. Engine sludge is a key contributor to engine failure; here’s how to recognize and prevent the problem.

What Is Sludge?

Sludge forms as motor oil oxidizes and breaks down, leaving behind deposits recognized as sludge. Sludge also forms due to moisture build-up and a lack of adequate positive crankcase ventilation (PCV). This glutinous muck is known to impede important oil pathways, including oil flow and return passages as well as filter elements. Engine sludge can even lead to severe damage necessitating complete engine replacement.

Can Sludge Be Prevented?

BMW M PowerEngine sludge can usually be avoided by following the manufacturer’s motor oil change guidelines. Most owners may follow a normal schedule, requiring oil change intervals of 5,000 or 7,500+ miles. However, if you operate your car in extreme conditions, such as city driving or off-road use, then follow the extreme-duty schedule. This typically means oil changes once every 3,000 miles.

Who Should Be Concerned?

Any changes in engine performance should concern you. A key symptom is an engine that has difficulty turning over. As long as the starter and all electrical connections are fine, spark should ignite promptly. You may also observe problems when checking the oil. Pull out the dipstick and if you notice globs of gelatinous material adhering to the stick, then sludge is likely present.

Is It Too Late to Fix?

Signs of engine sludge should serve as a red warning flag for vehicle owners. Once sludge has been detected it can be difficult to remove. Depending on sludge severity, the fix here may involve using a product such as Sea Foam, a fuel system additive, and synthetic motor oil, such as Valvoline SYNPower designed to combat three areas of engine stress: heat, deposits and wear. In more severe cases the engine will have to be disassembled and special tools used to remove sludge. This repair won’t be inexpensive, but it beats paying thousands of dollars for a new engine.

Are Certain Engines Susceptible to Sludge?

Simply because you carefully follow the manufacturer’s instructions doesn’t mean engine sludge build up won’t happen. Indeed, in the early 2000s, certain engines from manufacturers such as Chrysler, Toyota and Volkswagen were disposed to sludge accumulation for various reasons, resulting in engine failure. Take note of recalls and service bulletins related to your car and have all repairs handled immediately.

Be Careful When Buying Used

If you buy a new car, follow the manufacturer’s maintenance schedule to keep things running smoothly. Maintain your receipts because if something goes wrong, you have proof of the work done. If you shop for a used car, inspect the service records. Take a look under the hood; a burnt oil smell is a sign of a possible problem. With the engine off, remove the oil cap. Excess black deposits under the cap point to poor maintenance. Lastly, take note of the vehicle warning lights. If the check engine light is illuminated it may mean that the gas cap is loose, damaged or missing. On the other hand, it could point to more serious problems such as an oxygen sensor, mass airflow sensor, spark plugs or plug wires needing replacement.

Check out all the maintenance parts available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on engine sludge, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Photo courtesy of Wikimedia Commons.


Matthew C. Keegan View All

Matt Keegan has maintained his love for cars ever since his father taught him kicking tires can be one way to uncover a problem with a vehicle’s suspension system. He since moved on to learn a few things about coefficient of drag, G-forces, toe-heel shifting, and how to work the crazy infotainment system in some random weekly driver. Matt is a member of the Washington Automotive Press Association and is a contributor to various print and online media sources.

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