Sight glass in coolant tank leaking

[hotjag1]

Coolant is slowly running out at the base of the sight glass on my overflow tank. I noticed that the sight glass screws into the tank. Making sure it was tight didn't stop the leak.
Has anyone had to replace the sight glass? If so, is there an o-ring used at the base or is it a small gasket? Also, are either one of these available at auto parts stores? Thanks in advance.

[hotjag1]

Thanks hipower...I am planning on replacing the o-ring on Saturday and will put Teflon tape on the threads also. I just hope the sight glass isn't cracked.


UPDATE: I replaced the o-ring in the pressure tank. Everything went smooth with removing the plastic sight glass(not cracked). Old o-ring was cracked in multiple places(I'm surprised it hadn't leaked sooner).
I had already purchased the multiple pack of O-rings from Harbor Freight so it was easy fitting the proper size to the sight glass. Basically a 5 minute job sucking out some coolant with hand pump, replacing o-ring and sight glass, and putting coolant back in tank. Thanks everyone for all the good suggestions.

[hipower]

You've received good advice already so I won't repeat all of that. Some sight glasses are glass and some are plastic, really makes no difference which material, but be careful removing the one you have. From personal experience I had one crack at the base and leak. When removing it the threads snapped off and I had a pretty hard time getting the broken part out while on the road. No easy out in the tool box. There is a O ring seal and using a little teflon tape or paste on the threads makes the part a little easier to remove if you ever need to again. It also provides some added leak prevention although that usually isn't needed.

[hotjag1]

DSDP Don wrote:
Use a turkey baster to lower the level and then remove he sight glass. Harbor Freight sells a plastic container with multiple O-rings for about $5.00. It should have the size you need.

Thanks Don...your turkey baster suggestion sounds good, and there is a Harbor Freight store about 5 miles from me, so I hope it's just a deteriorated o-ring leaking.

[DSDP_Don]

Use a turkey baster to lower the level and then remove he sight glass. Harbor Freight sells a plastic container with multiple O-rings for about $5.00. It should have the size you need.

[hotjag1]

Thanks for all the good comments and suggestions. I do have a standard pressure cap on the tank. I didn't want to remove the sight glass and have an exposed hole until I was relatively sure that I can get a new o-ring at an auto parts store. I don't think the sight glass is cracked, but one poster said that they are readily available at truck shops, so I will check into that also. Thanks for all the good info!

[mtrumpet]

If yours is on a Spartan Chassis, contact Spartan directly. They will have the sight glass for the tanks.
Spartan Chassis aftermarket parts TOLL FREE 1.800.722.3025

Or, you might also try going to: www.rvchassisparts.com
They have parts available for both Spartan and Freightliner chassis'.

[crasster]

If it removable, I would remove it and see if there is an o ring or gasket.

[11178adm]

the sight glass screws into the tank and has a oring a standard hardware store oring will work. this type of sight glass has been used for years in truck and industrial applications, just be carful not to break it when removing it, if it breaks you can get one from any truck dealer or a radiator shop that repairs heavy duty radiators

[Mr_Mark1]

On our 2008 Dynasty with the 425 hp ISL Cummins, I had four Reservoir tanks. The first two were covered under warranty (apparently defective). The third one was defective that I paid for and the fourth was the charm!

My understanding is that they have to be replaced, not repaired.

Safe travels,
MM.

[jmac]

I have different engine, and don't have the sight glass, just the visual of the tank line indicating coolant level. I didn't notice until I was on the road, I15, near Saltlake when my overtemp light came on, I limped into campground in Filmore, UT . Filled reservoir made it to diesel garage in town, they put a tester on tank and sure enough had a serious crack/leak, they ordered a new reseviour tank , replaced it and we were back on the road. After couple days.Have your tank pressure tested.ASAP

[moisheh]

duplicate

[moisheh]

Does your tank have a standard looking pressure cap? If so it is not just an overflow tank. You cannot buy these at auto parts stores. Contact Tiffin for more info. But you might be able to stop the leak with sealant on the threads.

Moisheh