How to Repair an Oil Pan Drain Plug

Since an oil pan drain plug is removed and placed back in during every oil change, it is understandable that it will eventually wear out and need replacement. Replacing the oil pan drain plug is more advisable than repairing it, since the plug is relatively cheap and should function better. To prevent problems, replace the plug before it gives way to ensure that you don’t get an oil leak. Change it every couple of years just to be sure.

Materials

  • Bolt extractor set
  • Bench vise clamp
  • Hammer
  • Socket set
  • Lubricant spray
  • Thread pitch gauge
  • Rethreader kit
  • Tap and die set
  • Box-end wrench set
  • New drain plug gasket

Step 1: Preparation

In order to start on this project, you have to get underneath the car first. You have two options. One is to crawl underneath the car and work lying down. The second option is to lift the car using a hydraulic lifter. The second option is much easier and gives you more space to work while repairing the oil pan drain plug.

Step 2: Remove the Old Plug

Fit a bolt extractor into the head of the drain plug and use a hammer to pound it in. Do this with care and don’t overdo the pounding with the hammer. Insert the ratchet and corresponding socket into the bolt extractor and turn it counterclockwise to loosen the plug.

Step 3: Determine Measurements

First, determine the diameter of the oil pan drain plug by using a bolt diameter gauge. This is determined by the tightest fit that the gauge can move up and down the plug. Now find out the thread count with the thread pitch gauge. Once you have determined the measurements of the diameter and the thread count use the information to determine the correct rethreader die.

Step 4: Rethreading the Plug

Put the rethreader at the top of the shaft of the oil pan drain plug. Get the ratchet and corresponding socket for the rethreader and make the rethreader go to work by turning it clockwise. Apply some lubricant spray while you’re doing this. When you reach the end of the shaft, remove the rethreader counterclockwise.

Step 5: Rethread the Oil Pan Hole

Find out the corresponding size of rethreader or die for the hole of the oil pan and repeat the process found in Step 4. This will make sure that the threads of the hole of the oil pan are cleaned and that it will match the newly rethreaded oil pan drain plug. Again, get your ratchet and socket to accomplish this as in the previous step.

Step 6: Replace Old Gasket and Re-fit Plug

Fit the new oil gasket into the newly repaired oil plug. Put the plug into the newly rethreaded hole. Use your hands at first, turning the plug to tighten it. If it tightens perfectly, it means your rethreading was successful. However, if there is still some movement, you may have to replace the oil pan drain plug again.