Determining drain plug size and pitch.

Typically many newer vehicles have metric drain plugs. There are several
ways you can measure. You might try to bring your plug to a fastener house
to measure it or ask the dealer. Screwing a nut on the drain plug has also
worked to determine the size. If you have a measuring instrument like a
veneer caliper you can measure across the threads.

We also have a printable bolt chart that you could align the plug to get the
size and thread pitch. http://www.timesert.com/html/faq.html#22
This page of bolts will probably not look like your drain plug but that’s not
a problem what we are looking at is the thread size and pitch.