What's the best metal plug to screw in an aluminum radiator?

[78elk]

What's the best metal plug to screw into an aluminum radiator? I installed a Cadillac transmission cooler and want to bypass the radiator. I need plugs to fill the holes where the lines are going now.

 

[r_d_3]

If you get most of the trans fluid out you can probably just leave them open. Shouldn't be a problem.

 

[78elk]

Thank you. What's the best way to get the fluid out?

 

[r_d_3]

Thank you. What's the best way to get the fluid out?

probably pop the rad out and run your hose through the ports until no more trans fluid comes out, then the water will just evaporate, that's what i'd do at least.

 

[78elk]

Thank you. I really don't want to take the radiator out. I probably should try to get the fittings first. I may need to come back and use the radiator transmission cooler with the Cadillac external cooler.

 

[Killerdave8813]

They make special brass plugs that will fill the trans cooler ports in the radiator, available at about any auto parts store, tell them you need a plug for a female 5/16" flare fitting in the radiator and what you're doing and they should be able to fix you right up, I have them in my cars as they're both standard trans, KillerDave

 

[78elk]

Thanks Dave. I had a concern about brass with the reaction with aluminum causing it to rot out.

 

[Killerdave8813]

I wouldn't be too concerned about that, Brass and Aluminum are both non-ferrous metals and shouldn't react to one another adversely, now steel plugs might cause a problem but then again I'd bet your original cooler lines are steel and I imagine the fittings on those lines are steel as well, If you're that concerned wrap some teflon tape around the treads before you install the plugs

 

[78elk]

Thank you. That's a good idea. I'll give it a try. Much appreciated.