Montana Radiator Petcock

Ok, I have broke these before....can anybody tell me the proper way to open the radiator petcock to drain the cooling system?
Thanks!!

Turn it approximately 1/4 of a turn counter clockwise IIRC. I found an allen wrench works best for the style of plug that mine is fitted with. There were several styles though. As you turn it, allow it to pull out on it's own. It should remain captive inside the opening in the radiator.

The design for our van really is bad. It's hard to access and not easy to see what is happening. I've broke it the first time I tried to open it.

Turn it approximately 1/4 of a turn counter clockwise IIRC. I found an allen wrench works best for the style of plug that mine is fitted with. There were several styles though. As you turn it, allow it to pull out on it's own. It should remain captive inside the opening in the radiator.

The design for our van really is bad. It's hard to access and not easy to see what is happening. I've broke it the first time I tried to open it.


Does anybody know if GM sells a tool for this?

I'm sure they have some specialized tool...but any hardware store will have the allen wrench you need. I beleive a 1/4" ratchet with an extension also fits in the square hole

I'm sure they have some specialized tool...but any hardware store will have the allen wrench you need. I beleive a 1/4" ratchet with an extension also fits in the square hole

It was hard to see but to me it didn't look square?????

It looks like a wingnut and U cannot use allen key. Yes I broke mine too and used a small longnose vice use and gentley turn it out then use a wrench to pull the thing out and replace with another one. I just left mine there since it is not leaking.
It is a great PIS design !!!

It looks like a wingnut and U cannot use allen key. Yes I broke mine too and used a small longnose vice use and gentley turn it out then use a wrench to pull the thing out and replace with another one. I just left mine there since it is not leaking.
It is a great PIS design !!!

I think the design you are refering to is different than that on the 2000 Montana.....

on my '99, you turn the draincock 1/2 turn and pull and wiggle it as you are pulling on it. I used pliers and it took a little time and wiggeling, but it came. To close, push in on it and turn 1/2 turn back to the original position.


I think it went from this position __ to | position (turn counterclockwise) , then pull and wiggle.