Sight glasses keep leaking

Hello everyone

Just did my first run and noticed my sight glasses on my collection base was leaking like crazy. I think it’s because the gasket on the top part isn’t big enough. If I hold it down with my finger it stopped leaking but that’s no solution. Here are some pictures. The gasket seal on the top and bottom of the glass is 1.25inch. the bottom seems to be correct and I’m thinking the top is to small. As the diameter of the top screw on is 1.5 inches. So with the smaller gasket it’s not a covering the entire thing. Thoughts? Solutions? Should I try to find a 1.5 gasket and try?

Have you used a spanner wrench to tighten it real good?


Since I have no idea what that kind of wrench is no I have not. I will go get one today and try. I guess I will also get another flat washer /gasket made from Nitrile that is 1.5 inch. Both together should stop that leak.

a gentleman on the board help me with my very first run and we have problems with leaks right from the beginning since we had to try to chase him down it became a nightmare took hours to figure out. but he was a great guy and lots of patients I want to thank him publicly here for all his hard work and effort and patience with me thanks again bad cookies!

Thank you as well Thirdfracture!!

1 Like

This is how you tighten your sight glass. If the gasket looks in good shape don’t get another, just get this wrench and give the sight glass a good tightening.


The gasket is slightly smaller on purpose, it will expand once squeezed which forms the seal. Ensure everything is nice and center and tighten down the sight glass. If you don’t have the wrench above, you can make do with a Pipe Wrench

image (use a rag to prevent too much scuffing of the metal during this process)

1 Like

I’ve personally used a pipe wrench for over 5 years. No problem getting them tight with a pipe wrench.


I also use a pipe wrench and a rag


Whats all this rag talk for??? Its stainless steel guys. Its gonna bare a few scratches over time…

Pipe wrench to metal. Get a good grip. and tighten properly.


I feel so bad scratching all that shinny SS you sell me. :rofl::rofl::rofl:


I don’t know about you but I enjoy getting aroused when I approach my beautiful shiny collection pot and gently stroke it’s sight glasses. Gotta keep them as nice as they were when you sent them!


Get a strap wrench for taking off oil filters in cars they have a seat belt like strap that rap around, no scratches supper tight and any size u like

1 Like

you didn’t pressure test before adding solvent?

that was asking for trouble…

all my machines are required to hold pressure for DAYS before they see solvent.

usually it takes several attempts to get them to hold. they’ve never come in the door leak free

In addition to pressure testing your rig thoroughly when it comes in the door or after you do any mods on it, you would ideally pressure test & vacuum test before every run. losing air or N2 is one thing. leaking hydrocarbons is a totally different ball game.

many skip the routine pressure tests, and substitute just the vac. problem is, you can pass a vac test with clamps unbolted. but as soon as you add solvent…


No strap wrench or rag lol get a spanner wrench from Home Depot for your two inch sight glass . The sight glass is attached to what’s called a DIN fitting u need to tighten it with a wrench in order to seal it properly. If u need new seals get viton only as it will seal proper. Glacier tanks has em under the DIN fittings catagory


extremely good advice right here. I’ll add, make sure you test with adequate pressure… At the end of my pressure testing when I was chasing down the last leak, I thought I had it all fixed but since I didn’t want to run my compressor I was only able to put 45psi in there. It was fine at that pressure for a couple of days. I put 100psi in there and had a leak right away. I had to tear it down 3 more times before I finally fixed it. My last leak was a tiny leak that didn’t show any bubbles when submerged in water at 100psi. I was losing 3-5psi over a couple of days. It ended up being a valve that needed the packing tightened just a hair.

The best thing you can do is make sure your system will hold pressure for an extended period of time, and regularly test it, especially for those running super cold temps… Fireballs aren’t on my list of things to bathe in anytime soon :rofl:

I run my system once a month at most, so after each run I’ll clean it out with alcohol really good, let it dry overnight, then pressurize it until the next run.


I like a chain wrench in a pinch

1 Like

Thanks for all your help everyone! I got a wrench and tightened the sight glasses. Will test tomorrow!


Got coilovers?


Did you use a strap wrench? Another poster suggests a light coat of mct oil. DAMMIT old THREAD. I have similar sights and they seal.