I'm interested in methods of leak testing the coolant system. In my line of work I usually plug open ports & charge with air. I install a gauge Tee and a ball valve. I put about 160 lbs pressure & leave for as long as possible. Sometimes hours, sometimes months. I then note any pressure drop.
Will something like this work on an assembled emgine?
How many lbs pressure would you want to use?
How about to test the entire cooling system?

Stant makes a coolant pressure tester that hooks to your rad cap, and most auto systems are 12-15 psi max. this tester can also help find a leaky head gasket/cracked head. as with the tester hooked up and running a cold engine the pressure will rise and show on the gauge, another indication is a fluxuating/irrattic reading while the engine is revved up.

Will this work on ours where the Rad cap is on the expansion bottle?

I am also interested in testing an uninstalled block or assembled engine sans cooling system.
could you apply more pressure?
Has this been covered before?
I'm also interested in ananswer to the previous question posted by jsspringator.
Thanks

Will this work on ours where the Rad cap is on the expansion bottle?

It should as the rad cap on there is the same as on older GM vehs. and the expansion tank is subject to coolant system pressures and vacuums.

I would think an engine block on the stand can be tested in the same manner if all the ports were blocked, I'd fill the engine with coolant or water so that any leaks can be found right away. and you don't have to guess if its one off the blocked off ports or your hose connections to get air pressure in there. again I'd stay under 15psi

It should as the rad cap on there is the same as on older GM vehs. and the expansion tank is subject to coolant system pressures and vacuums.

I would think an engine block on the stand can be tested in the same manner if all the ports were blocked, I'd fill the engine with coolant or water so that any leaks can be found right away. and you don't have to guess if its one off the blocked off ports or your hose connections to get air pressure in there. again I'd stay under 15psi

The manner in which I leak test involves isolating the system with a ball valve & gauge. Hose leaks & hose connections are no longer part of the equation. This manner works well for everything else I have used it on. I would not want water involved. You determine whether or not you have a leak by pressure drop, Once you pressurize the system (system being assembled motor only) you isolate it - turn inlet/outlet ballvale to closed position. If the pressure drops you have a leak. Air will go where water won't. Especially on a cold system.

Ok, if you hook it up the way you are talking about, and suspose your connections don't leak..... you pressurise the system and you find it has a leak, now you know it leaks but how do you find it? the engine can leak anywhere, headgasket, cracks in the head, cracks in the coolant jacket etc, at least with water you should still see a pressure drop and water will pool near the leak, even if it is internal into a cyl with the injectors out you will find the leak.
This is just my impression as in my jobI don't do leak testing, as you do.:)

I have the stant kit, works great, except it couldnt find the leak in my headgasket until the truck got warmed up.

Ok, if you hook it up the way you are talking about, and suspose your connections don't leak..... you pressurise the system and you find it has a leak, now you know it leaks but how do you find it? the engine can leak anywhere, headgasket, cracks in the head, cracks in the coolant jacket etc, at least with water you should still see a pressure drop and water will pool near the leak, even if it is internal into a cyl with the injectors out you will find the leak.
This is just my impression as in my jobI don't do leak testing, as you do.:)

The first step is to determine if there is in fact a leak or not. If there is a leak you have an identified problem. Most often you can recharge the system and find the leak as leaking air will usually make noise. The higher the pressure the easier it is to determine if & where any leak might be. Leaks at hole plugs or test fittings are rare & easily found. I would think that an assembled engine could hold a fair amount of pressure. I would like to know exactly what pressure that might be. I could be way wrong here as the coolant system isn't rated at very high pressure & by overpressurizing the engine you might blow a head gasket or something.
Thanks

Ok I got what you are saying about the air leak and noise.I can buy that. as for how much the block can hold, I don't know, I only know what the cooling system is rated at, I supose if you don't have a water pump installed(because of the seals) you could jack the presure up. the headgasket should hold a fair bit as it has to hold against 400psi in the cyl. I'm guessing it could hold alot as the normal 15 rad pressure is low enough to raise the boiling point of coolant and not rupture hoses and waterpump seals, Just a guess but with all the burstable stuff removed maybe 60 or 70 psi or even more should be ok, cause really the only things left is the headgasket(if in good shape shold not leak anyway) and all metal parts anyway, so like you said if there are any cracks the air should excape. maybe you could test the engine prior to rebuilding to see what it could hold,
Just had another thought on the headgasket it might hold lots of psi on the cyl side, but not so much on coolant side as there are passages closer to the edge of the head which may not have enough gasket to withstand extreme pressure.( I just talked myself in and out of the same arguement)
Nick

You & me both. This is a little differant than what I'm used to doing. I'm sure there's somebody here that could give us specifics.
Thanks

just curious