Coolant Leak extrernal on head gasket ??

Sodium Silicate is the name for liquid glass. Permatex made a can product at one time that was pretty good. look online you'll find several. bars leak never worked good for me when I had a shop. The best way to do it is drain and flush coloing system and then use product. There are some that claim you can install and leave in without flush or draining. I never used any of them but it's been several years since I closed shop to.
If you have a three head cummins you can replace just one gasket if you can determine which one is leaking? If you go that route and head bolt is broken get a machine shop to drill out bolt unless you have a set up for it.
Last cummins I had done was when the counter bores were bad to leak and middle bolts broke. Shop had a mobile set up and came out cut counter bore, set protrusion and dril out broken bolt. I would look at all my options, these guys that say they'd do this and that will as long as it isn't their money they're spending.

 

How old and how many miles does this truck have? You should hunt down a few good mechanics and get some repair estimates. I would weigh my options and check all my figures before deciding.
I have to say to be careful with stuff like Bars Leak and the like. It can stop the leak but I have heard of people getting clogs in their radiator and causing overheating problems.

 

I would wonder how long it would last after a gasket?
I have seen lots trucks with well over 700,000 .
Pull an oil anylasis and see if any problems are dedected and I would make my descision after that. If Gasket replacement looks like a reasonable option I would do that and drive it awhile longer and save more money for another truck. thing about buying atruck is you could get a worse one with less miles. If your old truck is running ok otherwise I would hang onto it for a few monthes if possible after buying another truck just incase the new one is more trouble than old one. I bought my wife a durango with half as many miles as the old chevy 1500. I have spent more I think in repairs in less then six monthes as the chevy had spent on repairs in 9 years.
then again If I had a cummins needing a gasket I would just roll up the door and open the tool box.

 

I think I'd try the head gasket then. What state are you in? That can effect cost a lot. I had a freind with a 60 series head gasket seeped slightly for like four years not sure if it ever gave out or not. So you may have a little time depending on how bad it is.

 

What if its seeping into the cylinder overnight? It will eventually contaminate the oil, or worse hydraulic a cylinder...

Dont mess around with a blown head gasket, $1,800 2 days downtime, done.

 

oil anylasis are really only any good if done over a period of time to establish a baseline. If it were me I would trade it as is it is a leak on the exterior of the gasket so i would be thinking the head is warped not oil and water mixing. On the boats we ran exterior leaks and fixed them when fishing seasons closed interior leaks needed to be fixed right away. How much water are you losing daily?

 

Not to mention, coolant in the oil will eventually pit the bearings...bad juju. Does your oil look kinda milky or have blotches of light brown or the coolant dirty? If it is not blowin white smoke then I agree with transam pete. Hope all works out!