Topic: whats a good sealant for threads on my radiator drain plug?

[weakyota91]

so my radiator started very semi leaking today under just pressure from hot outside temp its (motor cold sat all night) leaking from the drain plug threads, with the radiator getting as hot as they do under operating temp whats a sealant i can use, just some regular rtv silicone? im assuming just as if i was sealing up any other water passage. im assuming the white tape u put on the ends of air compressor fitting (to stop air leaks) will not hold up to hot coolant and would just melt? ive gotta drain the radiator and would assume ive gotta get everything completley dry before i expect the silicone to do its job.

[emsvitil]

teflon tape is good for 500 F, so it wouldn't be a problem on a radiator........

[Vang530]

I'd use teflon tape too..no problems so far on my dad's truck but it was a gas line for a carb
Cleaning up silicone every time I had to drain coolant would be a PITA

[Cheesemaker]

Teflon tape for the win.


But what is the problem exactly?  Is the threads all jacked in the threaded portion of the radiator drain, or is the drain plug the jacked part?  I know that most drain plugs are plastic, and can get brittle over time, and just get a new one.  And if the radiator is still in good condition, I'd just tap out the hole with new threads, and put a bolt in with some teflon tape, and be good.

[Dr Phat]

Locktite makes a white thread sealant that I found works pretty good if teflon wont do it cause of bad threads or if you cant use teflon tape.

[weakyota91 [OP]]

cheesmaker no threads are fine and i kinda lied its actually not the drain plug but next to the drain plug is a little 1nch long tube like a drain spout or something (both are metal) but i didnt know teflon tape was good to 500 degrees thats a double win. since i will have the rad drained i will pull both the drain plug and little tube thats leaking and seal up the threads and see if this fixes my prob. (driving to fordyce) sept 21st and want to fix a few minor things. thanks dr phat i will defintly invest in some of that white thread sealnt sounds like some good stuff

[OOPS]

That is not a drain tube, that is a cooler for an automatic transmission. Most aftermarket radiators come with them, that way the do not have to stock two radiators.

[brainlessfool]

I use bubble gum.

[Cheesemaker]

I'm gathering that you have a manual transmission?!?!  Correct?  And if this auto trans cooler section of your radiator is leaking, then you have issues with the radiator.  Because, the automatic cooler lines that goes into your radiator is a separate system inside your radiator.  Get what I mean?  So, you don't get your oil in your water, or water in your oil.  I'd just invest in a new V6 radiator.  Because if your leaking there, where else are you gonna start leaking at? 

[weakyota91 [OP]]

ya its a 5 speed i put this radiator in the truck new (from napa) in 04. been good for me ive actually had coolant "cauliflower" built up i this area for honestly probly 5 years and would get wet and it was so mild the heat from the hot radiator would just evaporate it pretty quickly, so your thinking that teflon taping these threads  will only put a big bandaid on the problem for who knows how long 20 miles or another year....... im not disagreeing with u im gonna attempt to fix it first bviously wont cost me anything and drive it for a few days and see what happens Thanks everyone for the help and learned a little info about teflon tape lol

[Cheesemaker]

Yeah, just pop out the fittings, and tape them up and see what happens. 

Another question, about the radiator, is it one of the cheaper models with the plastic caps on the top and bottom?  If it is, I'd really look at maybe there might be a crack there.  And like you said, the hot days has caused it to leak more recently.  Maybe if its the plastic top and bottom, maybe it might have a small crack there. 

I put a plastic tanked radiator in my truck, because it was the last item to go in, and I ran out of money for a higher end all metal radiator.   So, I'm always watching mine. 

[weakyota91 [OP]]

no its not a cheaper model its all metal tanks and the weird thing was i drove it probly 30 miles today and it didnt leak but a drip of coolant sits at the threads and never hit the ground i will give the teflon tape a try when i finish painting and primering my winch bumper i bent up last week finally got my winch back on after 4 years (kinda a procrastinater i guess) i will drain it tonight and tape it up tomorrow

[junya92toy]

Well then maybe it has a hairline crack, and the thermal expanding, seals it

[emsvitil]

If it has a copper tank and the tube is copper,   add some solder and flux to the joint at the tank and hit it with a plumbing torch.........

[junya92toy]

Use the torch first, not the other way around

[weakyota91 [OP]]

junya very good idea i honestly didnt think about hairline crack and expanding metal causing the leak to seal up bingo i bet thats it thanks im gonna try the torch trick before i drain it or even jb weld??? good idea or just to redneck and lazy

[weakyota91 [OP]]

ok just to kinda update everyone and all the help ive got here on this thread im not trying to turn this into a science project but ive kinda determined that my tranny cooler (for a auto) may be corroded to sh*t and had caused this leak and basically a ticking time bomb i dont want to be carrying with me on the trail. ive drained the rad tonight and will take it to a radiator shop friday and see if they agree with me, see if it can be repaired if not i pull the credit card out and stick a new one in. i just put longfield axles in a month ago to prepare for my fordyce trip 21st-23rd this month i dont want to keep thinking and worrying about something like the radiatior i just wanna wheel and have fun. trail side repairs are not fun 

[emsvitil]

Since you don't need the tranny cooler......

Just plug it and solder the openings shut.

[Cheesemaker]

I'd just get a new radiator.  If the tranny cooler is corroding, what else is corroded?