Fixing Oil Pan Leak: Sealing The Rear Main

If you're reading this, you probably have an oil leak. The first thing to do is to make sure it's engine oil that's leaking and not another type of lubricant. If it is engine oil, you'll need to identify the source of the leak. Oil pan leaks are often the leading cause of car leaking oil, but they can also be caused by a worn drain plug or a leaking oil pan gasket. If you have a leaking oil pan gasket, you may be able to fix it by tightening the bolts, cleaning the surfaces, and applying a new gasket or sealant. If the oil pan itself is cracked, you may be able to repair it with a cold welding compound, but if the crack is large, you'll need to take it to a mechanic.

Drain the engine oil

Before you begin, make sure you have the right equipment to do the job. You will need a new oil filter, a funnel, and a container to catch the oil. You will also need safety equipment, including safety glasses and gloves.

First, park your vehicle on a level surface, engage the parking brake, and turn off the engine. If necessary, raise the front of the vehicle by driving it onto a ramp or jacking it up and supporting it with jack stands. Never get under a vehicle that is only supported by a jack.

Next, locate the engine oil dipstick and remove it. This will help the oil flow when draining. Put on your safety glasses and crawl under the vehicle to locate the engine's oil pan. You can refer to your owner's manual for reference.

Now, locate the oil drain plug. This is a long bolt head at the bottom of the oil pan that allows the oil to drain out. Some vehicles have two drain plugs. Position your container under the drain plug, making sure it is large enough to hold the volume of oil expected to drain out. Check your owner's manual for the volume of oil your car requires.

Loosen the drain plug using a box-end wrench or 6-pt. socket. Carefully remove the plug by hand, ensuring the container is underneath the plug hole. Oil will flow rapidly, so be cautious. Allow several minutes for all the old oil to drain out. Refer to your vehicle's owner's manual for additional information. Caution: the oil may be hot!

Once the oil has finished draining, wipe the oil pan threads and oil drain plug with a rag. Visually inspect the condition of the oil pan and oil drain plug threads and gasket. Buy a replacement drain plug if the current one appears worn. Replace the drain plug gasket if needed—some OEMs recommend this. Reinstall the oil drain plug and tighten it with the correct box-end wrench or 6-pt. socket to the manufacturer-specified torque, as per the owner's manual.

Clean the oil pan mating surface and the bottom of the engine block

To clean the oil pan mating surface and the bottom of the engine block, you will need to remove the oil pan. This can be done by following the steps outlined below:

• Park your vehicle on a level surface and use jack stands to raise it.
• Disconnect the cable at the battery's negative terminal.
• Place a suitable container under the oil pan and remove the drain plug to drain the oil.
• Remove the oil pan bolt, gasket, and oil pan.
• Clean the oil pan mating surface and the bottom of the engine block with a solvent to ensure a perfect seal. You can use mineral spirits or brake parts cleaner for this step.
• Once the surfaces are clean and dry, you can proceed to the next step, which is installing the new gasket or sealant.

It is important to note that you should consult a repair manual or seek professional help if you are unsure about any of the steps or procedures.

Apply cold welding compound to the cracks

To apply cold welding compound to the cracks, follow these steps:

• Combine the cold welding compound according to the package directions.
• Spread the compound liberally on the cracks.
• Allow the welding compound to dry and cure completely as directed on the package before refilling the engine with new oil.

It is crucial to properly prepare the surface to which you are applying the cold welding compound. It must be completely clean and dry for the compound to work.

Wait for the compound to cure

Once you have applied the cold welding compound to the crack or hole in the oil pan, it is important to wait for it to cure. This usually takes between 15 to 24 hours. During this time, the compound will fully cure and effectively seal the crack in the oil pan.

While you wait, it is important to keep the car off the road. Even if you have used a quick-curing epoxy, it is best to wait until the recommended curing time has passed before driving your vehicle again. This will ensure that the repair is strong enough to withstand the vibrations and heat of the engine and road.

It is also important to note that a repaired oil pan may not have the same structural integrity as a new one. While a repair can last the remaining life of the vehicle, if you plan to keep the car for many years, it may be worth considering replacing the oil pan instead. A new oil pan will provide better long-term durability and peace of mind.

In the meantime, you can take this opportunity to inspect other components of your vehicle and perform any necessary maintenance or repairs. By being proactive and comprehensive in your approach, you can help ensure the reliability and longevity of your car.

Finally, always refer to the instructions and recommendations provided by the manufacturer of the cold welding compound. They will have specific guidelines and safety precautions that should be followed to ensure the best results.

Refill the engine with oil

Once you have replaced the oil pan, you can refill the engine with oil.

Park your car on a flat surface and ensure the engine is turned off and the keys are out of the ignition. Open the car's front hood and locate the oil filler cap. It should be a round, black cap, typically marked "engine oil" or with a drawing of an oil can. Remove the cap and place a clean funnel at the top of the spout to prepare to add the oil.

Double-check that you are using the correct oil for your car. You can find this information in your car's service manual. Then, add about half a quart of oil. If your oil level was in the "add" section of the dipstick when you checked, you'll likely need to add at least one quart of oil, but it's better to add it in smaller increments to avoid overfilling.

After adding oil, re-check the oil level using the dipstick. If it still needs more, add another half quart and check again until the dipstick shows there's enough oil in your engine. Once your oil is at the proper level, remove the funnel and replace the oil cap and dipstick before closing the hood.

It is important to maintain the correct oil level in your engine to ensure your engine doesn't suffer from premature part failures. You should check your oil level regularly and change it as recommended in your car's service manual, typically between 3,000 and 10,000 miles.

Frequently asked questions