Checking the Fumoto threads against the stock drain plug threads isn't going to tell you whether or not the Fumoto plug will prevent complete draining of the oil pan. You need to check it against the depth of the oil pan threads. I would be surprised if the oil pan was as thick as the drain plug threads are deep (~3/4" to 1" if I remember correctly) and would almost guarantee that the stock plug extends up above the bottom of the oil pan.

True. Your logic makes sense. I had a subaru oil pan apart before and the plug area is reinforced and built up to be flush with the end of the plug. I assume that this is the general case, since there seems to be like a dozen or so standard oil plug sizes that are used by most car/truck mfgs.

From Fumoto's FAQ:


Q. Does my Engine Oil Drain Valve protrude into the interior of the oil pan and prevent full drainage of my engine oil?

A. No. The threaded oil drain plug hole is always reinforced to accept the threaded bolt of the drain plug. In most cases, the Engine Oil Drain Valve will not extend past this threaded portion of the drain hole and will allow the oil to be properly drained. Your Engine Oil Drain Valve will let you drain your engine oil while it is hot without burning your hands and it is much more effective than trying to pump the oil out from above.

If assuming the above is correct, then the fact that the fumoto valves threaded section was the same size as the original plug, then there should be no drainage problem. But, next oil change I will measure to be sure <img src="/forums/images/graemlins/wink.gif" alt="" />.

If that's the case I might pick one up.
I just changed my oil on Sunday and if this thread had been posted earlier I could have checked. Oh well, only about 2950 miles to go until the next change. PM me with what you find out. <img src="/forums/images/graemlins/cheers.gif" alt="" />