How to Prevent Motor Oil Sludge

Oil changing is among the most important vehicle maintenance tasks. New, unused engine or motor oil is a transparent, easily flowing liquid that combines base stock and a collection of additives. These additives can hold soot particles and maintain the consistency of the engine oil. Oil lubricates the moving parts of the engine and in this way, not only reduces friction but also helps to keep the engine cool. With frequent use, the motor oil accumulates coolant, dirt, water, fuel and other contaminants. It also breaks down or oxidizes because of the intense heat of the internal combustion engine of your car. As a result, it turns into sludge, a thick gel-like fluid that can cause serious damage to your engine.

How motor oil works

Engine or motor 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 oxidized sludge causes a buildup of heat in the engine. Motor oil functions as a coolant to some extent, but oxidized sludge acts as the opposite. You’ll notice that the oil pressure is falling, and you get lower mileage per gallon of gas.

Motor oil sludge first develops on the top of the engine, the valve cover section, and in the oil pan. Next, it blocks the oil screen 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. Ultimately, the engine could stall completely.

Common reasons for engine oil sludge buildup

  • Engine oil is unstable and tends to oxidize when exposed to oxygen under conditions of high temperature. Oxidation can occur faster if the engine oil is heated over extended time periods.

  • During oxidation, the molecules of engine oil break down and the resultant products combine with the dirt in carbon form, metallic particles, fuel, gases, water and liquid coolant. Together the mixture forms a sticky sludge.

  • Stop-and-go driving in heavy traffic conditions and in areas where there are lots of traffic lights can contribute to sludge buildup. Frequently driving over short distances can also cause sludge.

Keep in mind

  • When you turn the ignition on, check the dashboard for the Check Engine Light and the Oil Change notification light. Both could indicate that the motor oil needs replacing.

  • Review the owner’s manual that your car manufacturer provides for instructions on when to replace the motor oil. Typically, manufacturers give you the mileage increments in which to replace the engine oil. Book an appointment with YourMechanic accordingly.

  • Avoid stop-and-go driving as much as possible. Walk or bike over short distances to prevent motor oil sludge buildup.

  • If the dashboard gauge shows that the car is heating up, have your mechanic check for motor oil sludge also.

  • It is never advisable to add engine oil if you see that the oil pressure is low. If the oil pressure light is on have it inspected or replace it completely.

How it’s done

Your mechanic will check the engine for signs of a sludge accumulation and let you know if the motor oil needs replacing. He or she may also check for the other possible reasons why the Check Engine Light is on.

What to expect

A top-rated mobile mechanic will come to your home or office to determine the cause of the various signs of motor oil sludge. He or she will then provide a detailed inspection report that covers the part of the engine affected by the motor oil sludge and the cost of the necessary repairs.

How important is this service

Make sure you follow your owner’s instructions manual and have YourMechanic replace the motor oil regularly. It is essential that you do this or you risk severe damage to your engine. You might even have to replace the entire engine and that can prove to be very expensive repair work. YourMechanic uses top-quality Mobil 1 conventional or synthetic oil to prevent sludge buildup.


Next Step

Schedule Oil Change

The most popular service booked by readers of this article is Oil Change. YourMechanic’s technicians bring the dealership to you by performing this job at your home or office 7-days a week between 7AM-9PM. We currently cover over 2,000 cities and have 100k+ 5-star reviews... LEARN MORE

SEE PRICING & SCHEDULING

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Recent Oil Change reviews

Excellent Rating

(28,142)

Rating Summary
26,601
957
209
107
268
26,601
957
209
107
268

Pardeep

22 years of experience
1277 reviews
Pardeep
22 years of experience
Scion xB L4-2.4L - Oil Change - San Jose, California
Pardeep was very professional. Finished all works in a timely manner. Will again avail of his services when the need arises. Highly recommended.
Ford Fusion - Oil Change - San Jose, California
Great experience. Of all the online services, this one makes sense. I got the oil I wanted and great service

Simon

28 years of experience
378 reviews
Simon
28 years of experience
Mercedes-Benz 190E L4-2.3L - Oil Change - Washington, District of Columbia
He was on time, courteous, efficient, speedy, and advisable about certain things to be aware of for future service. Please send him every time, as he seems to be very much aware of the mechanics and engineering of my car more so than all the others who have serviced it...He pleases me utmost. in the professional service I requests.
Chevrolet Malibu - Oil Change - Washington, District of Columbia
EXCELLENT experience!!! Simon is friendly, courteous,and professional. Very customer oriented. He answered my questions with knowledgeable replies which made me feel comfortable. He also came out on his day off to work on my car. Which speaks volumes on how he strives to take care of his clients. Definitely will book him for any car problems or services I need in the future.

John

21 years of experience
650 reviews
John
21 years of experience
GMC Sierra 1500 V8-5.3L - Oil Change - Howey In The Hills, Florida
John was great, Knowledgeable, professional and got straight to work. He was on time and finished expeditiously.
Kia Sportage - Oil Change - Orlando, Florida
John was professional and very nice. He also explained some issues I was having with my car and what I should and should NOT do. He was able to wxplain it to me without being condescending in any way. I will request John every time going forward!

Shawn

13 years of experience
379 reviews
Shawn
13 years of experience
Nissan Altima L4-2.5L - Oil Change - King Of Prussia, Pennsylvania
Shawn was awesome!!!! Professional, knowledgeable, kind, courteous and very thorough. Please thank him for me.
Lexus IS300 - Oil Change - Norristown, Pennsylvania
Shawn is always professional, honest, easy to talk to and always on time. I've never had an issue working with him and will continue to book him as long as he's available.

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

Related articles

How to Lubricate Your Car's U-Joints
U-joints allow the driveshaft to keep up with the movements of your car's suspension system. Keeping them lubricated will prevent wear and noise.
Signs Your Car Needs an Oil Change
Oil changes keep your car engine running smoothly. Rough idling, slow acceleration, and engine noises mean you need to replace your car oil.
The #1 Guide to Oil Change Coupon Codes (Updated 12/2020)
The most extensive guide for navigating oil change coupons and discounts.

Related questions

Oil on electrodes of spark plugs and cylinders
First, visible amounts of oil on the spark plug electrode is never a good sign. To me, if the vehicle starts and struggles to run, there may be a major mechanical malfunction regarding your explanations. Have the mechanical timing checked...
I have an oil leak and dealership is telling me can't be fixed
Hey there. I have never heard of an oil leak that cannot be fixed. Even if the engine had to be replaced. The oil leak can be fixed. I recommend having a different mechanic give a diagnosis of the leak...
2012 Chevy Malibu oil change
The oil filter should not be damaged by over tightening it, however you may want to be sure that the threads on the filter were not damaged by tightening it too much as this may cause it to leak. Generally,...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com