How to Clean Piston Rings

Co-authored by Audra Fordin

Last Updated: June 9, 2024 References

If your car is running poorly and is giving off a lot of exhaust, then dirty piston rings might be to blame. But how do you fix that? In most cases, a good cleaning will fix the problem right up. This can be a complicated job, especially if you haven’t worked on cars much before. Luckily, we’re here to answer all your questions about the process!

Question 1 of 7:

What do the piston rings do?

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Piston rings prevent fuel and exhaust from leaking into your engine. In a normal car, each piston has 3 rings wrapped around the piston head. Together, these rings keep oil and exhaust out of your engine during the combustion process, helping the car run smoothly. ^{[1]
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- The 3 piston rings are the compression ring, wiper ring, and oil ring, in order from the top of the piston to the bottom. All 3 work together to keep your engine clean.

Question 2 of 7:

How do I know if the piston rings are dirty?

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Low engine power and high exhaust are the main signs. Over time, oil and gunk build up around the piston rings, meaning they won’t move as well and could freeze up entirely. When this happens, fuel and exhaust will leak into the engine and the engine’s performance will fall. The main signs of this are a high amount of white or black exhaust coming out of the car and decreased power when you accelerate. ^{[2]
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- There are also other reasons for high exhaust or low power. If you aren’t sure what the cause is, bring your car to a mechanic to diagnose the problem.
- These are also the symptoms of bad or broken piston rings. In this case, you’ll need to replace them entirely.

Question 3 of 7:

Can I clean the piston rings myself?

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Even if you use a simpler method to clean the piston rings, it’s a lot of work and any mistakes could damage your engine. If you’re not used to working around cars and engines, then it’s best to leave the job to a professional. Otherwise, if you’re handy and comfortable working with cars, go for it!

Question 4 of 7:

What’s the best way to clean piston rings?

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Remove the pistons and scrape the residue out for the best results. This is a big job, and you’ll have to remove the engine by draining all the oil, disconnecting all the wires and pipes, unbolting the engine and transmission, then lifting the engine out of the hood. After that, pull the pistons out of position from the bottom of the engine. Once the pistons are out, take the 3 rings off and spray the grooves with parts cleaner. Scrape any gunk or buildup out of the grooves with a flat tool. ^{[3]
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Expert Source

Audra Fordin
Certified Automotive Technician

Expert Interview. 13 January 2022.} Also spray down the rings themselves and wipe them with a rag. Then reassemble the pistons and put them back into the car. ^{[4]
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- There is a specialized piston-cleaning tool called a groove cleaner, so this would be your best choice. Some mechanics also just use an old, broken piston ring to clean the grooves, since it fits perfectly into the slot already.
- Most part cleaner spray will work. Just make sure you use a de-greaser or carbon cleaner designed for automotive use.
- This is a complicated job that requires a good deal of automotive skill. If you haven’t worked on cars before, it’s best to leave this to a professional.

Question 5 of 7:

Can I clean the piston rings without removing them?

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Pour injector cleaner onto the pistons to dissolve some deposits. This is a quicker method that doesn’t require taking the engine apart. Remove all the spark plugs around the engine first. Then pour a bit of injector cleaner into each fuel injector slot. ^{[5]
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Expert Source

Audra Fordin
Certified Automotive Technician

Expert Interview. 13 January 2022.} Let the pistons soak for 8-10 hours to dissolve any buildup. Then crank the engine for a few seconds without putting the spark plugs back in to clear the fluid. After that, put the spark plugs back in and start the car. ^{[6]
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- This doesn’t clean the rings entirely, but it could dissolve some of the gunk and make the car run smoother.
- Don’t spill any injector cleaner or you could overflow the engine. Use a funnel to avoid spills.

Question 6 of 7:

Will flushing my engine clean the piston rings?

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It can make the rings move better, but it won’t actually clean them. An engine flush basically circulates oil through the engine to get rid of gunk and buildup. This can actually get some of the gunk off the piston rings to keep them loose, and might improve performance temporarily, but it’s not a long-term fix. It doesn’t remove enough gunk from around the pistons to really clean them. ^{[7]
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- An engine flush is still a good way to clean the engine and keep it running well. It’s just not a good solution for dirty piston rings.

Question 7 of 7:

Can I prevent my pistons from getting dirty again?

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Not entirely, but you can cut down on buildup with good maintenance. Cars get dirty; it’s just a fact of life and you can’t stop that from happening. The best thing you can do is slow the process down with some maintenance tips. ^{[8]
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Expert Source

Audra Fordin
Certified Automotive Technician

Expert Interview. 13 January 2022.} These won't prevent buildup entirely, but they will cut down on it and keep the engine running well. ^{[9]
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- Use good quality gasoline to reduce the amount of buildup and residue in your engine.
- Make sure your car’s oil is always topped off to keep everything running smoothly.
- Change your oil and oil filter at the recommended times for your vehicle.

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Can I clean piston rings?

Audra Fordin
Certified Automotive Technician
Audra Fordin is a Certified Automotive Technician, the Founder of Women Auto Know, and the Owner of Great Bear Auto Repair in Flushing, New York. With more than 38 years of experience, she has intensive knowledge about foreign and domestic auto repairs. Audra has been featured on numerous news and talk shows such as The Today Show, Inside Edition, and Anderson Cooper.

Audra Fordin

Certified Automotive Technician

Expert Answer

You definitely can, but you're better off going to an auto shop if you want a thorough cleaning. Car shops use a special 3-stage process with an IV-style drip to clean out the pistons, which is a lot more efficient than physically taking apart the engine.

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Tips

Taking your car in for an annual inspection can catch any issues like dirty pistons before they get too serious.

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Warnings

If you have any doubt about working on the car yourself, then bring it to a professional. Any mistakes could damage the engine and make the car dangerous to drive.

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Audra Fordin
Certified Automotive Technician

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How to Clean Piston Rings

Steps

What do the piston rings do?

How do I know if the piston rings are dirty?

Can I clean the piston rings myself?

What’s the best way to clean piston rings?

Can I clean the piston rings without removing them?

Will flushing my engine clean the piston rings?

Can I prevent my pistons from getting dirty again?

Expert Q&A

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Warnings

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