Filling a cooling system properly can sometimes be aggravating. A stubborn air pocket in the entire system or the block itself can cause the engine to run hot, or you might discover the heater doesn’t work properly. Getting those air bubbles out can prove challenging. One way to do it is to take the radiator cap off and put a big funnel into the filler neck or surge tank. The idea here is to start the car and watch the bubbles work their way out. I’ve even used a floor jack to move the car up and down and side-to-side in an effort to purge the air.
There are better ways, of course. One is to use a tool like Astro Pneumatic’s Master Universal Pressure Tester & Vacuum System Kit. This kit allows you to pressure test the cooling system and radiator cap as well as purge and vacuum fill the cooling system. It’s all pretty slick.
Case-in-point is the radiator cap pressure tester. The kit provides two adapters. Just choose one that accepts your cap and select the appropriate steel test cap from the kit–there are three of them and each has a steel quick coupler fitting at the top. To use, install your radiator cap on one end and the test cap on the other. Attach the hand pump from the kit and pump it to up the pressure specification for your cap. You’ll quickly find out if it holds the pressure or not. I tested a 15 PSI cap and it checked out OK at just under that number.
Testing the cooling system for a leak works much the same way. This time, select the cap adapter that fits your radiator or surge/expansion tank. With the vehicle cooled down, replace the radiator cap with the cap adapter, attach the hand pump, and pump it to the desired operating PSI (it should be the same rating as the radiator cap). Watch the gauge as you reach operating pressure. If the pressure drops on the gauge, you know there’s a leak in the system somewhere.
Purging and refilling is pretty simple too, but you’ll need an air compressor. The tool creates a venturi effect, essentially introducing a vacuum in the vehicle cooling system. This draws in coolant with little or no chance of creating air bubbles.
A quick note: You’ll see the engine compartment of my Corvette is empty, so I couldn’t test the system or draw coolant into it. But the images showing tool setup are correct.
Here’s the Astro Pneumatic Master Universal Pressure Tester and Vacuum System Kit. You get a pressure testing pump with gauge; a purge/refill tool with pressure release and vacuum gauge; radiator cap test adapters; and 17 cap adapters for testing cooling systems on most domestic and import vehicles. (Image/Wayne Scraba)Most of the adapters are numbered and color-coded. The kit comes with a chart showing the applications for each of them. (Image/Wayne Scraba)If none of the adapters work with your radiator, this universal adapter has a pliable rubber body that can be forced into the cooling system filler neck. (Image/Wayne Scraba)The Astro Pneumatic kit includes these adapters that allow you to pressure test your radiator cap. (Image/Wayne Scraba)Here’s the radiator cap pressure testing adapter with a reproduction AC RC15 cap. The cap goes on one end and one of the steel cap adapters is installed on the other. (Image/Wayne Scraba)To pressure-test the radiator cap, attach the cap adapter to the hand pump. Pump to the pressure that matches the radiator cap and watch the gauge. If pressure drops or continues to drop after you reach the cap’s pressure rating, the cap is defective. (Image/Wayne Scraba)The hand pump is also used to pressurize the cooling system to check for leaks. Install the radiator cap on the radiator or the surge/expansion tank. Hook up the pump as shown here and bring the system up to the factory operating pressure (this matches the radiator cap rating). If it holds pressure, all is well. If pressure drops, then you have a leak somewhere. (Image/Wayne Scraba)Setting up the radiator purge/refill tool requires an air compressor. The tool creates a venturi effect, essentially introducing a vacuum in the cooling system. This draws in coolant with little or no chance of creating air bubbles. This hook and chain is used to hang the tool body over the radiator. (Image/Wayne Scraba)The blue hose with the quick coupler attaches to the radiator cap adapter for your application. (Image/Wayne Scraba)The valves on the purge/refill tool are numbered. To start the process, the number 3 valve must be turned open. Open is in line with the fitting. Meanwhile, the number 6 valve just below the vacuum gauge must be turned closed. Closed is 90 degrees to the fitting. (Image/Wayne Scraba)The airline from your compressor hooks up to the tool as shown. Push the yellow slide button to “on” as shown and wait until the vacuum gauge reads between 50-60 cm/HG. Turn the Number 2 valve to the off position (90 degrees to the fitting), then slide the button to “off”. (Image/Wayne Scraba)Connect the quick coupler on the supplied clear coolant hose to the tool. The other end of the hose is submerged in a container of coolant. (Image/Wayne Scraba)Turn the number 6 valve to the open position. The tool will then automatically refill the cooling system. The refill is complete when the vacuum gauge reads zero. During the process, keep an eye on the coolant level—you don’t want the supply hose to start drawing in air. Double check the amount of coolant in the system, too. You might have to add a small amount manually by very slowly pouring in the coolant. You don’t want to create bubbles. (Image/Wayne Scraba)
Wayne Scraba is a diehard car guy and regular contributor to OnAllCylinders. He’s owned his own speed shop, built race cars, street rods, and custom motorcycles, and restored muscle cars. He’s authored five how-to books and written over 4,500 tech articles that have appeared in sixty different high performance automotive, motorcycle and aviation magazines worldwide.
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One response to “Purge, Refill and Test Your Cooling System with an Astro Pneumatic Master Universal Pressure Tester and Vacuum System Kit”
Uso como utilizar esa herramienta para purgar