Oil Drain Hole Threads Stripped


New member
The threads for the oil drain plug hole on my 2.4l 1986 Westy are stripped. For awhile I got by with the bolt not tightening all the way, but stupidly ignored this until the bolt actually unthreaded and fell out while I was driving. Fortunately I was able to stop and get a temporary expander-type plug before any real damage was done, but now even a 14mm oversize is too small.
I would like to either repair or rethread the hole. It is currently too big for a 14mm bolt of any thread pitch, so as I see it my options are to try to cut it to 18mm with a tap or try some of that thread repair compound and a 14mm oversize plug. Any advice appreciated!

Jason Rolfe

New member
Posting here to check a couple things.

1. Wondering if the OP ever got the problem fixed, and how.

2. I've got an 87 Westy, and I somehow managed to strip out the drain plug hole (I think my cheap torque wrench is to blame:eek:). I've been reading about doing the Heli Coil repair, which seems pretty solid. But, I'm not exactly sure which repair kit to buy. From what I've gathered, I'll need the properly sized drill bit, the tap(?), the coil insert and the insert installation tool.

Do I just need to buy the kit that is made for an M14 x 1.5 bolt? Is there anything else to look for with this kit?

Thanks in advance for any help.



New member
Hi...I had the same problem..I used a pipe tap to retap the hole and a pipe plug to fit, in the pipe plug I drilled a #7 drill and 1/4-20 tap, then a 1/4-20 screw with a copper washer. After cleaning out the hole with some kind of brake cleaner, use locktite on the plug. It takes a few more minutes to drain the oil but it worked for several years until I put a rebuilt Go Westy 2.4 engine in my 91 Westy.


New member
A good machine shop will be able to help you with a heli-coil. Did mine 5 years and 15 oil changes ago and still holding fine. Good luck!