Coolant drain petcock

[jmp88]

After splashing antifreeze all over my garage while trying to control its flow out of my radiator, I started looking for easier options. I found this thread http://www.bmw2002faq.com/component/option,com_forum/Itemid,0/page,viewtopic/t,303286/view,next/sid,1c38ff903c60466be0bc34a78a7c0053/ about NPT valves almost fitting but being a slightly wrong thread pitch.

Then after some more googling, I found this guy: http://www.mfgsupply.com/m/c/23-12110.html

Am I wrong, or will this work? That O ring + extra space at the bottom of the threads looks a little funky. Seems like it would work still right?

[Mike Self]

petcock in the block drain...

I realize the threads are different and that it isn't the ideal solution. That being said...the petcock is brass; the block is cast iron, so if there's gonna be thread deformation, it will be to the petcock threads. And once the petcock is installed, you're not gonna be removing it to drain the block.

I used Teflon tape to seal those slightly mismatched threads; That was back around 1994-95, and there have been no leaks or thread failures in the intervening time.

I figured that a little thread persuasion was better than dribbling antifreeze all over the place, particularly since at the time I had an extremely curious (and not terribly smart) cocker spaniel...

Now if someone has found a source for metric thread petcocks, that would be great, as the same problem exists with the OEM radiator. I had to file the threads off a brass petcock and then solder it into my radiator tank to make a tight seal.

cheers

mike

[jimk]

Then after some more googling, I found this guy: http://www.mfgsupply.com/m/c/23-12110.html

Am I wrong, or will this work? That O ring + extra space at the bottom of the threads looks a little funky. Seems like it would work still right?

Not funky at all if you know how straight threads are sealed. Take a look at how your oil drain plug or temperature sensor or radiator drain plug are sealed.

If the threads are the correct size/pitch and length of threads match, of course it is a very good match.

NPT threads are not at all the right ones.

[Tiger75]

I think the petcock from mfg supply will work. I checked the threads on my drain plug and they are 14mm X 1.5 so the threads should fit.

I ordered one but they are back ordered. I should get it in a few weeks