Sight glass material?

[Iceni John]

I want to make a sight glass for my coolant header tank so I can easily see how much is inside without having to shine a flashlight or dip a stick down inside.   I want to use some transparent rigid tube, but polycarbonate has a maximum temperature rating of 200 F.   I'm thinking that may be too close for comfort to the coolant's temperature, even though the coolant in the header tank is probably not quite as hot as that in circulation.   There are some other super-expensive high-temperature clear plastics, but nothing available that I can buy in 12 inch lengths of 5/8" or 7/8" OD (to fit inside 1/2" or 3/4" SharkBite fittings).

Has anybody here made their own coolant sight glass, and if so what did you use for it  -  glass, plastic, what?

Thanks, John

[Darkspeed]

This would work > http://www.ebay.com/itm/Pyrex-Corning-Boiler-High-Pressure-Gauge-Sight-Glass-Tubes-18-X-3-4-H678-/351534822676?hash=item51d91bb514

You will need to use the correct fittings as well > http://www.ebay.com/itm/New-Sight-Glass-3-4-np-Liquid-Level-Brass-Fittings-Lot-of-2-Free-Shipping-/380715223365?hash=item58a4654945

Also found these > http://www.ebay.com/itm/New-Coolant-Sight-Glass-Fitting-01-68324-000-Gillig-/141366440302?hash=item20ea18b16e&vxp=mtr

[Iceni John]

Yes, that's looks better than what I had in mind!   How does the glass tube fit inside the fittings?   Is it an O-ring seal, or what seals it?

Thanks, John

[Darkspeed]

Yes, that's looks better than what I had in mind!   How does the glass tube fit inside the fittings?   Is it an O-ring seal, or what seals it?

Thanks, John

I have used them on fire supression systems and they have to survive extreme temp most I have seen have a high temp double o-ring or double ferrule. They are popular in the home brew scene as well.

Such as > http://www.bargainfittings.com/index.php?route=information/information&information_id=9

[Melbo]

This is what I installed by my surge tank

It is connected to an led in the dash so I know if I am low on coolant

http://www.fwmurphy.com/products/level-devices/l150

Melbo

[Iceni John]

Thanks for all those good suggestions.   I had thought about a SwichGage, but its hole locations don't work for me  -  I already have a 1/4" lower fitting in my tank and a 1/2" upper fitting, so I want to Tee into them.   Unfortunately they're some weird dimension center-to-center which means I can't use a ready-made sight glass or a Swichgage.   I just want to be sure that any gauge I make won't eventually leak or burst  -  even with a Low Coolant sensor for the DDEC (which I haven't tested, yet), coolant losses are not a good thing.

The home-brewing folk may have just what I need.   I'll research that avenue further.   Good idea.

Thanks, John

[Darkspeed]

Thanks for all those good suggestions.   I had thought about a SwichGage, but its hole locations don't work for me  -  I already have a 1/4" lower fitting in my tank and a 1/2" upper fitting, so I want to Tee into them.   Unfortunately they're some weird dimension center-to-center which means I can't use a ready-made sight glass or a Swichgage.   I just want to be sure that any gauge I make won't eventually leak or burst  -  even with a Low Coolant sensor for the DDEC (which I haven't tested, yet), coolant losses are not a good thing.

The home-brewing folk may have just what I need.   I'll research that avenue further.   Good idea.

Thanks, John

just make sure to use boiler rated glass like my first link if it is high temp / pressure. it can be cut to size with a bench grinder - with some practice. I grind it on an edge until it turns red hot then i work my way around.

[chessie4905]

   Some of the older buses had two petcocks in the surge tank. One at max low and one at normal desired level. Some of these were push button petcocks. Push the top and a little comes out, good to go. None; push the lower- coolant comes out either add to top or check again at next startup. None comes out....it had to go somewhere. Or fill to top petcock and check again sometime later. 4905's have a low coolant sensor probe and module identical or very similar to the ones used in GM cars in the 80's and 90's

[kyle4501]

I just added a coolant recovery tank to mine - found it on eBay - 3 gallon capacity.

Works GREAT!

[Boomer]

On my Eagle I welded a bushing into the surge tank and installed the MCI sight glass, as far as I know they are still available at MCI.  Let me know if you need the part #.

[luvrbus]

I just use the Trico sight kinda like Boomer is talking about,you can buy the glass rods and fittings to build what ever you like from WW Grainger,Boomers type is a lot better on a bus than a glass tube IMO and only 1 fitting to deal with also the least amount of fitting on a bus the better chance of survival   

[moosemanusa]

The surge tanks from modern RTS (Nova) have the sigh glass and the sensor for low coolant. lots floating (no pun) on ebay.. if you need a Gxxxxx part number let me know.

[Iceni John]

And I thought this would be a simple project!   Is anything bus-related ever simple?

I want to use my existing tank if possible because it's bolted to the radiator frame, and a new tank will need a new mount.   Is the MCI-style sight glass a single-ended connection with its top open to atmosphere, or is it a closed double-ended gauge?   Is there any appreciable pressure inside the coolant tank when it's at operating temperature?

Thanks, John

[luvrbus]

The systems run 5 to 7 lbs of pressure at operating temperature, I just use the round Trico or other brands they come in different sizes some have marking,plain, finned it's what ever you choose but I have never saw a tube sight style on a bus before 

[muldoonman]

On my 91 prevost surge tank, it  has a round site glass towards bottom.  Don't see how you can get inside tank to hold a back up on site glass models unless you cut tank open. 

Cliff,  Does that 7 pound rating cap good for the 8V92TA's also??