Radiator Inspection Question

[Neira]

I cleaned up the radiator for my '41 Dodge 3-window coupe and wanted to inspect it for leaks.  I read a comment somewhere that these 218 engines were 0psi systems.  I just wanted to see at what PSI are most people are inspecting their radiators to.    

[Sam Buchanan]

Fill it up with water and see if it leaks?

[andyd]

Well..I'd check to see what pressure the radiator cap is listed at and if anything check it at that psi rating.........but generally as Sam says, fill it with water & check for leaks.....radiator shops have a special radiator cap that has an air hose fitting, the upper & lower outlets are sealed off and the cap fitted and compressed air is run into the radiator with it submerged in a tub of water.......easy to see if any bubbles appear and where these are from .........dunno if this helps you much..........andyd 

[Sam Buchanan]

18 minutes ago, andyd said:

Well..I'd check to see what pressure the radiator cap is listed at and if anything check it at that psi rating........

 

This a non-pressurized system, it has an open vent and the cap won't hold pressure regardless of how it's rated. 

[kencombs]

I bought a cooling system pressure tester.   HF but works good.  Plug the overflow, and hose outlets,  put the adapter on the cap, pump up to 2-4lbs and submerge in water.  Hope for no bubbles.   Works on the car too to test for core plugs, gaskets etc.

[Sniper]

1 minute ago, kencombs said:

I bought a cooling system pressure tester.   HF but works good.  Plug the overflow, and hose outlets,  put the adapter on the cap, pump up to 2-4lbs and submerge in water.  Hope for no bubbles.   Works on the car too to test for core plugs, gaskets etc.

 

I have a setup that puts the cooling system under a vacuum, about 23" if I remember right.  That'll show a leak too.  But finding it though.  Pressure would help find it, that and a squirt bottle of soapy water. 

[Dan Hiebert]

Yes, the cooling systems in our cars are pressureless.  But pressureless means they don't use pressure to raise the heat range of the system, it doesn't mean they won't take any pressure.  Either way, filling with water, or with air while under water, works.  Not as much equipment needed to fill with water, but you need a keen eye, and you can still miss tiny holes.  Filling with air takes a tub of some sort, and as andyd notes, some fittings to seal up the inlet and outlet.  I had a couple radiators checked at a local shop recently, they used some of those rubber freeze plugs with the bolt that tightens to seal the inlet, outlet, and filler neck.  Then they ran air at low PSI into the overflow tube.  Not sure how much PSI they used, but the systems in our cars can handle 4 PSI just from expansion of the coolant.  Readily and quickly apparent where the leaks are via that method.  

[kencombs]

2 minutes ago, Sniper said:

 

I have a setup that puts the cooling system under a vacuum, about 23" if I remember right.  That'll show a leak too.  But finding it though.  Pressure would help find it, that and a squirt bottle of soapy water. 

That's how systems are filled at the factory I understand.  And bigger shops sometimes use them for coolant fill as a lot of newer stuff is really hard to get all the air out for a gravity fill.   I actually have used my A/C vacuum pump and parts of the pressure test kit to rig up such.  Never really used it, just proved I could if needed.

[desoto1939]

Of note the cap that was used on your car is an R-3 radiator cap.  You can find everseal caps model r-3 on ebay. We had a zero pressurized system.

 

Rich Hartung

[Sniper]

28 minutes ago, kencombs said:

That's how systems are filled at the factory I understand.  And bigger shops sometimes use them for coolant fill as a lot of newer stuff is really hard to get all the air out for a gravity fill.   I actually have used my A/C vacuum pump and parts of the pressure test kit to rig up such.  Never really used it, just proved I could if needed.

 

You are exactly right and that is how I do it now.  Tired of burping air bubbles out of cooling systems

[Neira]

Thanks everyone for the info. I’m probably gonna put 2psi with water in it and see what happens. I have rubber caps to seal off the connections. The HF tool has worked for me on other projects.