Coolant level "view glass" weeping coolant while parked

[dbsoundman]

Hi all, my FE Thomas bus has a small glass(?) bulb at the top of the radiator that's supposed to be used to check the coolant level. First of all, the bulb is kind of dirty so it's hard to actually see the coolant level, but second, I noticed today that it seems to be leaking a little bit of coolant from the bottom of the bulb. The weird thing is I haven't started the bus in a week, so I'm not sure why it would be actively leaking now?


Here's a pic of the bulb I took previously, I can get a new pic with the leak shown later today. It's a very small leak, just a few drops, enough to leave a little bit of a wet spot at the top of the radiator.




What's also interesting is that this leak didn't start until after I ran the bus last, which was just idling in the driveway for about 30 minutes while I tested the air system a bit.

[Tin Roadtube Vagrant]

Be pretty easy to eliminate. Looks like the transparency was gone anyway...

[dbsoundman]

Originally Posted by Tin Roadtube Vagrant

Be pretty easy to eliminate. Looks like the transparency was gone anyway...

Not sure I want to eliminate it as it's a useful thing (only way to check the coolant level in this kind of bus), but I did consider depressurizing the system so I could pull it off and try to clean it?

[BamaBus]

Originally Posted by dbsoundman

Not sure I want to eliminate it as it's a useful thing (only way to check the coolant level in this kind of bus), but I did consider depressurizing the system so I could pull it off and try to clean it?

I wouldn't eliminate it. You may be able to remove the smaller nut and replace the o-ring or put more sealant on the threads, depending on what is leaking. Be prepared to temporarily plug it off but the size and thread pitch can vary. It will leak if the radiator is full. There are some flat clear radiator sight glasses online that seem to be easier to see the coolant level.

[EastCoastCB]

They sell those sight glasses for like ten bucks or less.
That tank looks fairly rusty... I got a whole new tank with sight glass for less than a hundred shipped.
Edit- just realized you're dealing with one on a radiator, not a tank.. Still should be able to replace it cheaply.