Modine Pet Cock

So I got a new Modine radiator, installed it, and basically all my temperature problems went away - which I'm totally thrilled about it.

The new radiator came with a brass petcock fitting, and a note that basically said turn the petcock into the radiator a little, and if it leaks, turn it in a little bit more until it stops. The note also said that you shouldn't turn it in all the way or it'll damage the radiator and void the warranty. It also mentioned teflon tape.

Today I did alot of driving and tightened it twice to get it to stop leaking. After I tightened it the second time, it seemed to stop, but I'm a little bit worried about how far I had to tighten it. I'm not 100% sure it stopped for good either - I'm hoping it did. I have the grill off so I can keep an eye on it.

Since this is the first time I've done this, I think I underestimated the importance of teflon tape. I should've acquired some. My bad, totally.

Basically, my question is ... am I cool? ... Should I be concerned about 1) how far I have the petcock screwed in, and 2) the fact that I didn't use teflon tape? (assuming it has stopped leaking)

Use the tape, that's what it's made for.

Just or information, I put a threaded elbow in, ran a rubber tube down and through the dust shield. Hangs about an inch below the dust shield and the valve at the end, makes draining the radiator a snap.

I never used any tape on mine. Just screwed it in till it stopped and never had any leak problems. You should be fine.

Thanks guys - I guess some reassurance is all I'm looking for. I know I should've used tape, but whats done is done. I'm just looking for a "you'll be fine", or a "you'll have a problem with that".

I appreciate your feedback so far! I also want to thank everyone for pointing me in the direction of this Modine radiator. I've been nickel-and-diming this temperature problem for months. The new radiator was finally the ticket.

The petcock is screwed into the radiator bung with pipe threads... here's a brief explanation of how pipe threads work. Pipe threads are slightly tapered, which is what provides the sealing action, an interference fit between the male and female components. When you add teflon tape, it lubricates the threads as they are tightened against each other, which allows you to tighten the assembly more easily and smoothly. The teflon tape does not actually improve the seal itself. So if you were able to make it stop leaking without the teflon tape, you should be fine. The reason they warned against screwing the fitting all the way in is that the largest outer diameter of the taper will eventually crack the bung into which it is screwed if you crank it in too far, causing a leak. Sounds like you will be okay.

Usually when I do this kind of thing I coat the threads with indian head gasket cement. I'm more worried about leakage so the IH cement provides a barrier against that. I also use it on the the hoses, coating the first 1-2 inches or so with the stuff. It comes loose between the hoses and bung with a bit of slipping a small screwdriver in there to break it loose. Generally when I use it on the drain petcock I put it on, snug the thing up and let it set/dry for 20 min or so. Just makes life easier...