KCvetteowner

The cork on my oil pan drain plug finally broke off. I purchased a new plug but the threads are wrong. What threads do you have on your oil pan? Mine are fine (I don't know how else to describe the bolt threads). I'm not original owner so I'd like to find out if the oil pan is original and if the hole has been re-threaded.

Lst-rd-c4

I am assuming your talking about a nylon washer on the plug, never seen cork used on a drain plug. My 96 has an O-ring on it. I would check with your dealer for the proper plug. As to the threads I'm not sure if they are standard or metric but there around 3/8 or 7/16 fine. I would be sure to have the right plug before tapping the pan for a generic plug. Hopes this helps.

Wadoka

I think the plug thread is 1/2-20 UNF. But I'm not 100% positive. I'll check it out and get back tomorrow.

KCvetteowner

It sure looked like cork. The new one I got has a rubber o-ring llike you said and magnetic tip, nothing like what I took out. I'm not the original owner, this might be my first "non-stock" encounter. :eek:

Anyone know how a novice measures the threads so he can tell what the heck everyone said in his thread?

Wadoka

If you have precision measuring tools, caliper/mike the plug across the threads. 1/2-20 should measure .487" to .499". Then, if you don't have a pitch gage hold the plug up to a ruler and count how many thread peaks you have in an inch. If you don't have a decent set of dial calipers (everybody needs a pair, right...?) then you can eyeball the inch/millimeter approximate on a ruler.

If it's an SI bolt, (which it probably ain't) It'll check about .472" (M12) or .512" (M13). You'll have to convert your diameter to metric, and get the inverse of the pitch. Metric bolts are rated in millimeters per thread, instead of threads per millimeter.


[Modified by Matt Black, 8:00 AM 8/4/2001]