Last updateWed, 18 Oct 2017 10am

On The Road

Change oil regularly and use the correct kind

Q: My car’s engine started making noise. I found that the engine oil was low, so I added some. The noise didn’t go away, and then the Check Engine light came on. I brought my car to a repair facility and was told that the engine had a large amount of sludge inside, causing my problem. Do you agree that this is possible? What is sludge, and what caused it to occur in my engine?

A: The answer to your first question is yes, and you are not alone with this experience. As automotive manufacturers continue to reduce vehicle maintenance requirements and extend oil-change intervals, this type of problem is becoming more common. We see it because the intervals are longer and people tend to forget and wait way too long before having their fluids changed.

What is sludge? As engine oil accumulates miles, it becomes contaminated with carbon, water and various acids – all of which are by-products of the engine’s internal combustion – and forms a film of black, gooey sludge on the interior parts of the engine. That’s why oil needs to be changed periodically.

What causes sludge buildup? It is important to understand that today’s engines require oil with different additives than cars from many years ago. The different manufacturers are also requiring their own oil and additives, so there is no longer a one-size-fits-all oil application.

Knowing this, it is also important to understand that going somewhere for low-cost oil changes (i.e. $19.95) is almost a sure bet that you are not going to get the correct oil and filter installed for your vehicle. The wrong engine oil can even lead to premature internal parts wear – whether or not there is sludge buildup.

Be aware, too, that neglected oil-change intervals – or not checking your engine oil levels regularly – may starve your engine for oil and result in sludge and varnish buildup. Even the best engine oil can be ruined by such neglect.

Other causes of sludge buildup include cold-engine operation – which accelerates sludge buildup because oil temperatures are insufficient to evaporate the moisture that accumulates inside the engine – and short-trip, cold-weather driving and thermostats that are stuck open, which can have the same results.

Many automobile manufacturers install high-quality synthetic lubricants in their vehicles at the factory. This type of engine oil has a much lower tendency to create sludge and works better with the design changes inside the engine.

What should you do now?

It might be possible to flush out the sludge and hope that the internal engine parts aren’t damaged. If there is damage inside the engine, you’ll need a new or rebuilt one.

In the future, make sure that you follow the manufacturing service schedule and check your vehicle’s fluid levels frequently. Even if your vehicle did not come with quality synthetic oil, using synthetic oil is always a good idea, and there is no problem with switching from petroleum-based oil to synthetic oil at any time.

Warren McCord is an ASE Certified Master Technician and owner of Dean’s Automotive Inc., 2037 Old Middlefield Way, Mountain View. For more information about the repair shop, call 961-0302 or email McCord at This email address is being protected from spambots. You need JavaScript enabled to view it..

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