After scrapes and cuts I finished installing a new water pump on my 85 GT. Just tried to fill with anti-freeze and its leaking from around the metal pipe that came with the new pump and had to be screwed in. I took the pipe back out and even with thread tape on it and turned fairly tight it is still leaking. What is the best thing to use on the threads to stop this leak? Thanks

I would use Permetex form a gasket sealant (comes in a tube). But, there may be better things, and I would talk to an auto parts store to see what is available for exposure to coolant.

use napa# 765-1188, thread sealant with teflon. It is like pipe dope for home plumbing.

dan

Thanks guys. I went to the auto parts store on the corner and got some permatex thread sealant made for cooling systems. I just re-installed it and I am going to let it sit overnight. It is white like plumbing pipe dope.

quote Originally posted by Csjag: Thanks guys. I went to the auto parts store on the corner and got some permatex thread sealant made for cooling systems. I just re-installed it and I am going to let it sit overnight. It is white like plumbing pipe dope.

perfect!

Wow this water pump replacement is a real pain! The little leak wasn't coming from the bolt threads it is coming from the top edge. Evidently some of the sealant go rubbed off when I was putting the new pump on and it didn't seal, there is so little room to work I was unable to push it straight on. Back off it comes, darn it. This time I am taking the battery tray off, that really scraped me up before. Changing the water pump on my duke was 100% easier!

Thoughts on using a gasket and some high-tack sealant?? I only installed a V6 waterpump on a engine that was out of a car. I have done multiple 2.5l water pumps and yeah, they are pretty easy.

There are a few scratches on the mating surface from scraping off the old gasket and I would worry that it would leak if I use a gasket instead of permatex gasket maker

quote Originally posted by jaskispyder: Thoughts on using a gasket and some high-tack sealant?? I only installed a V6 waterpump on a engine that was out of a car. I have done multiple 2.5l water pumps and yeah, they are pretty easy.

Success! I went to NAPA this morning and bought the aircraft high tack sealant. I cleaned off the permatex gasket maker and used the gasket and the high tack gasket sealant, it made it easy to get the gasket to stick to the pump. Pump is installed now and leak free. Thanks for everyone's help.

I did manage to break off the small bolt that is inboard close to the center but I covered the hole with jbweld and it is not leaking.