small leak in coolant system

Gents, I've had a small weep in my cooling system, which believe came from the WP inlet nipple. It's tucked away in a pretty inaccessible place, and after pulling the coupling apart, I felt a little roughness on one side of the nipple. Getting a remote camera on it, it appears to be crystalized Dex Cool. I've sanded the junk off using 320 grit sandpaper, and it feels smooth now, with only very tiny remnant. Between the difficulty of getting at this thing, and a desire not to remove too much material on the nipple, I think I'd like to stop now. What's the feeling on using anaerobic flange sealant or some such material to "reinforce" the junction between the nipple and a silicon hose?

Howard Jones

If I was doing this I think I would apply a small amount of RTV to the small area that had the "tiny remnant" spot and put the hose back on, tighten it down and see if that fixed it.

Don't use a lot of RTV just attempt to seal the tiny spot. Too much RTV can make it be hard to remove the hose later.
^ thanks for that. I stopped myself from doing exactly that out of concern for sticking later. One problem is that when the hose is pushed onto the nipple, it will drag the RTV with it, and I want to keep it off the clean aluminum as it can't really improve seal on virgin metal. I may elect to just re-assemble as is, and hope it works out. Otherwise, I'll have to drain the system again, which is not much fun.


I used silicon hoses throughout in mine and most leaked until they had been warmed up and tightened a few times.


Shaun, I've posted this a few times before but this is the solution to that problem:



Indeed you did Neil I had fitted mine already with T Bolt Clamps but will try those next time, they wold be really good for the tight spots for sure
Just an idea - in the marine industry it's standard to use offset double hose clamps for all fittings that have to be water tight (below the water line).

Personally, I like to use the smooth band stainless Norma hose clamps on everything rather than the open/cut thread type as the smooth type seems to provide a better seal and damage the hose less.