How to Fix a Leaky Oil Filter

by Andrew Hazleton

You should change the oil filter on a vehicle every time the oil is changed. Changing the oil and filter regularly is one of the cheapest and most effective ways to prolong the life of an engine.

Occasionally an oil filter will leak after installation. A seal should form between the bottom of the oil filter and the flat plate around the oil coupler fitting. Oil in an engine is under pressure, and an inadequate seal will leak.

Verify that you have installed the correct oil filter. Check the numbers on the filter against the information provided by your vehicle's manufacturer. Oil filters are matched to a specific engine, not a specific model of car. Many models of car are available with multiple engine types, each requiring its own oil filter.

Verify that the filter is still tight. An oil filter should never be tightened beyond "hand tight", but a filter may sometimes become loose after it is installed. Re-tighten the filter and check for leaks.

Remove the filter and verify that it has not been cross-threaded upon installation. The metal of the filter is softer than the fitting on the vehicle, so only the filter threads would be damaged if the filter was cross-threaded. If the threads on the filter are damaged you will need to replace the filter.

Verify that the rubber seal is installed on the bottom of the filter, and is not damaged. Replace any filters with damaged or missing rubber seals.

Verify that the area where the seal mounts to the engine block is free of dirt, debris, or any parts of an old seal. Scrap away any dirt with a small putty knife. A small amount of a degreaser may help remove stubborn grime. Clean the threads on the oil filter fitting.

Use your finger to smear a small amount of oil on the rubber seal on the bottom of the oil filter.

Reinstall the filter and hand tighten. If the filter still leaks, replace it and install a new one. Check the oil level and refill as needed.

Tip

  • check Problems with oil filters are almost always with the seal, but occasionally one may leak at a seam in the housing. Replace as needed.

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About the Author

Andrew Hazleton has been writing on a freelance basis for more than 20 years, and his work has appeared in national, regional and in-house publications. His work has appeared in "Sports Illustrated," "IEEE Spectrum," "Popular Photography" and several newspapers. Hazleton has a Bachelor of Science in engineering from Lehigh University and a master's degree in management from Pepperdine University.