We often get calls from people who have damaged drain plugs or chewed out drain holes.

A stripped sump plug can be caused by not aligning and inserting the plug exactly perpendicular to the face of the sump pan. It is made worse by applying more torque using a leveraging tool (e.g. spanner, socket or hex key). It could also be caused by something caught in the threads as the plug is tightened.

Stripped sump plug

Once it is threaded, it’s not easy to back out the sump plug and thread it in correctly. If the damage is not too great and only the first one or two threads are damaged, it may be possible to clean up both the plug and the sump pan and get the plug back in correctly. A tap the same size as the sump plug can help in cleaning up the sump pan threads. Seeing a lot of metal material come out with the plug is a sure sign the threads have been damaged. It is also a worry if any material has made it's way into the sump itself.

Some sumps are more prone to damage than others. In particular, aluminium and alloy sumps. There are even sumps made from plastic which can crack when too much force is applied on the sump plug.

Damaged sump drain hole

We have a fleet customer that replaces all the sump plugs on their Mercedes-Benz (Actros) trucks with EZ Oil Drain Valves, just to avoid damaging the sump. They do this as soon as possible as they've found damage to the sump threads doesn't take long. A replacement sump is into the thousands and damage will occur again, in time.

It is often possible to replace the sump plug permanently with an EZ Oil Drain Valve if the damage isn't excessive. There are permament and semi-permanent thread-locking products (e.g. by Loctite) designed to take up the slack between the threads and creating a stronger, leak-free install.

If the damage is too great, the plug will not go back in squarely or will be a loose fit. In this case, the only remedy is a new sump or a quality repair of the drain hole by welding and retapping, threaded insert or helicoil. We have had customers re-thread their sump's drain hole to an oversize and then fit one of our valves. Our size guide lists all available sizes so a suitable oversize can be chosen.

Of course, you can always just put in an EZ Oil Drain Valve as a preventative measure for a stripped, cross-threaded or damaged sump.

Eliminate this

Stripped hex head drain bolt

And this 

Stripped bolt heads


Please refer to our size guide for a list of all sizes, or print out our measuring guide for a layout of all sizes, incrementally, and to scale.

If you have any similar stories or problems, we'd love to hear from you. Contact Us.