I have a 1953 GMC with a recirculating type heater. Is there an easy way to test the heater core for any leaks prior to hooking it up to the engine? I’d hate to have it leak all over the inside of the cab.
One way that I have done it is to block off one end, fill it with water than add a few lbs of air to pressurize. You’ll need to get creative with fittings. I would not add any more than 10 lbs as that may open up some seams.
Phil Moderator, The Engine Shop, Interiors and Project Journals
1952 Chevrolet 3100, Three on the Tree, 4:11 torque tube Updated to: ‘59 235 w/hydraulic lifters, 12v w/alternator, HEI, PCV and Power front Disc Brakes Project Journals Stovebolt Gallery Forum
Speaking of bicycle pumps. I've gotten a bicycle inner tube, chopped it in half putting the two cut ends of the inner tube onto the hear core outlets. Pumped the tube until it expands somewhere and then remove the pump. The pressure in the innertube will keep a constant low pressure on the core. submerge the core in a bath of water and look for bubbles.
Last edited by cmayna; 11/11/20201:53 AM.
Craig
My '50 Chevy 3100 5 window, '62-235cu, 3:55 rear My truck ....... Respect The Rust If I'm not working on my truck, '65 m00stang or VW camper, I'm fishing with the wife or smoking Salmon.
The other method...........rubber stopper plug in one hose connection.........hand vacuum pump like Mity Vac used in bleeding brakes. Draw a vacuum on the heater with a stopper in the other hose connection. Pump a vacuum ........should hold a vacuum if there’s no issues with the core.
This method works really well at the swap meet. No water no pressure needed.
I capped the outlet and connected the garden hose to the other and turned on the water. The air pressure methods above would be ideal. Pressurize it then submerge in water.
I capped the outlet and connected the garden hose to the other and turned on the water. The air pressure methods above would be ideal. Pressurize it then submerge in water.
Be careful connecting your heater core to the house water system...most houses operate from 30 to 60 psi (or higher if on city water) and that's way more than the core can handle.
Mike B
Mike Boteler
1956 Chevy 3100 Resto Rod 1952 Willys M38 Army Jeep 1983 Jeep CJ7 Laredo 1984 Jeep CJ7 +++++ Silver Spring, MD
I bought all the stuff to test my heater core: heater hose, clamps, barb fitting adapters, 1/2” cap, and a gas pressure test gauge at Home Depot for about $34. Then while driving I saw an old time radiator repair shop and talked to the old timer ... lo and behold he fixed the leaks in the heater core for $45 well worth the money, now I’m returning the test stuff to Home Depot
"I saw an old time radiator repair shop" THEY STILL EXIST.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
bicycle inner tube ,inflated and clamped overnight.
Perfect! Now let's see you use that inner tube next time your bicycle get's a flat. LOL
I like this method for it will only provide a low pressure.
Craig
My '50 Chevy 3100 5 window, '62-235cu, 3:55 rear My truck ....... Respect The Rust If I'm not working on my truck, '65 m00stang or VW camper, I'm fishing with the wife or smoking Salmon.
That is the reason I run my radiator with a 0 psig cap. My donut core is a fragile thing and I do not want to over stress the cooling system. I tried to find a local radiator shop that would repair that heater core and no joy. Most would just laugh when they saw it due to it's reputation. It has been several years (10-12) since I rebuilt that heater with a re-worked core from Maine Radiator who did an excellent job. No more steamed wind shields.
