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How to Quickly and Accurately Find the Source of an Oil Leak

leak on ground beside car

Engine oil leaks are the most common of all automotive fluid leaks. With the number of seals and gaskets located around the engine bay, oil can leak from almost anywhere.

If the leak occurred some time before you notice it, the oil may have spread far from the real source. Air moving through the engine by driving or being pushed through the cooling fan can cause the leaking oil to cover areas far and wide. Also, if it isn’t a large and/or obvious leak, it will take some investigating to locate the source as it may also be caked with dirt and debris.

Part 1 of 2: Use a degreaser

It’s best not to start replacing seals, gaskets, or other components until you locate the exact source of the leak. If the leak is not obvious, the easiest way to start looking for the source is with a cool engine.

Materials Needed

Step 1: Use the degreaser. Spray a little all-purpose degreaser on the area you see oil. Allow it to penetrate for a few minutes and then wipe it off.

Step 2: Check for a leak. Start the engine and let it run for a few minutes. Check to see if you can spot a leak below the car.

If there is no evident leak, then it may be small enough that it may take days of driving to become evident.

Part 2 of 2: Use a U/V leak detector kit

The fastest way to spot a leak is to use a leak detector kit. These kits come with fluorescent dyes that are formulated for specific engine fluids and a UV light. When the oil starts coming out of the source of the leak, the fluorescent dye will leak out with it. Shining the UV light around the engine bay will make the dye glow, usually a fluorescent green that is easy to spot.

Materials Needed

Step 1: Put the dye into the engine. Pour the leak detector dye into the engine.

  • Tip: If your engine is low on oil, add a bottle of the correct dye for engine leaks to the oil you’re adding to the engine, then pour the oil / leak detector mixture into the engine. If the engine oil level is ok, simply pour the dye into the engine.

Step 2: Turn on the engine. Run the engine for 5-10 minutes or even take it for a short ride.

Step 3: Check for oil leaks. Let the engine cool down before you start shining the uv light into tight spaces. If your kit supplies yellow goggles, put them on and start checking around the engine compartment with the uv light. Once you spot the glowing green dye, you’ve found the source of your leak.

Once you identify the source of the oil leak in your car, have it inspected by a certified service professional, such as one from YourMechanic.

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

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