[staleg]

At the bottom of my AFCO aluminum radiator, there are two threaded holes. One of them are plugged with som kind of "winged" plug. A drain plug maybe?The other one is open.
Any of you know the thread size on the open one? I need to plug that one, too.

[WDCreech]

It should be 1/8 NPT, but I can't garantee that.

Bill

[2old2fast]

I would guess it would be 1/4 " fpt, if you put a plug in it , make sure to use a good teflon thread sealer, prevents galling & leaks .

dave

[S10 Racer]

Originally Posted by staleg

At the bottom of my AFCO aluminum radiator, there are two threaded holes. One of them are plugged with som kind of "winged" plug. A drain plug maybe?The other one is open.
Any of you know the thread size on the open one? I need to plug that one, too.

The wing nut one is a radiator drain. The other is either an 1/8" or 1/4" NPT. The plugs are cheap so buy both just to make sure. Also, it would be a good idea to buy the brass plugs and use a good sealer on it. Stay away from steel plugs.

[MARTINSR]

Originally Posted by S10 Racer

Also, it would be a good idea to buy the brass plugs and use a good sealer on it. Stay away from steel plugs.

Very good advice, I wouldn't have thought of that.

Brian

[staleg]

An update on this one: The hole is actually 1/2" NPT threads. I've ordered a brass plug.

[S10 Racer]

Originally Posted by staleg

An update on this one: The hole is actually 1/2" NPT threads. I've ordered a brass plug.

Thanks for keeping us updated.

[timothale]

sometimes a heater hose was connected to the radiator.

[bondo]

Originally Posted by timothale

sometimes a heater hose was connected to the radiator.

Ayuh,.... That explains the huge size of it,...

[staleg]

One more update, i'm afraid.
Because of my lack of knowlegde, I thought 1/2" NPT male threads measured app 1/2" in diameter. That's not correct. 1/2" NPT threads actually measure 0,84 inches.

The correct plug size is 1/4 after all...
sorry for the mis-information.