Over the past few weeks we’ve looked at a ratcheting brake caliper piston spreader, a tool that’s better than a C-clamp, an advanced diagnostic scanner for deep down diagnostics and the humble digital caliper, a tool that makes measuring easy, if not fun. This week’s cool tool is a vacuum purge and refill kit that helps ensure your cooling system is properly serviced.
Readers have been asking me to feature air tools and your wish is my command. This one is recommended by fellow Volkswagen masochist Dieseldub, who recommends the tool for flushing coolant and removing air bubbles from any car. Getting the old coolant out is easy, but putting the fresh coolant in may present some challenges.
The internet is full of advice for refilling your car’s coolant system. You could directly fill the radiator or the coolant reservoir, I’ve even seen some people feed coolant into the coolant hoses. Go to an online forum and it’s easy to get confused at the various tricks people use.
And when you’re done filling the coolant, you’ll want to make sure there are no air bubbles in the cooling system. Having an air bubble or pocket in your coolant is bad news.
An air pocket can lead to your engine getting an inadequate amount of coolant, potentially leading to overheating. I may be dealing with this exact situation with my discount Volkswagen Phaeton.
The previous owner flushed the coolant system, but it overheats during any sort of highway driving, which could be from an improper fill.
Once again, there are numerous tricks out there to getting air out of a cooling system. Some cars have valves that you can open to release air while some cars will burp themselves of air if you park a certain way and leave the cap off of the reservoir.
The best way is to make sure you don’t have bubbles in the first place, and that’s where a vacuum purge and refill kit comes in. These systems work by creating a vacuum in your system. They then use that vacuum to pull coolant into the system, replacing the air. NAPA published an awesome tutorial on using one of these tools:
The tool is inserted into the neck of the radiator service port or reservoir tank using the best fitting adapter. It should be snug in the opening. Turn the knurled knob to seal the adapter in the hole. Connect the venturi vacuum module to the unit, with the ball valve open. Then connect the air line to the vacuum unit. This should start the process, you will hear a loud hiss, this is the air blowing over the venturi valve, which draws a vacuum.
The gauge should start climbing. Once it reaches 24-26 inches of vacuum, close the ball valve. Your radiator hose may collapse, that is normal. If you can’t reach this level of vacuum, you may have a leak or an overflow hose needs to be clamped off. Wait 20-30 seconds and check the gauge again. If it is stable, your system is not leaking and you can continue.
Insert the screened end of the fill hose into your coolant jug. Hold the jug as close to the same height as the adapter unit. Make sure the coolant jug does not run dry, this will push air into the system. Close the valve to refill the jug. Once the gauge reaches zero, the system is full.
The Watch Wes Work YouTube channel shows one of these in action:
The process takes just a few minutes. No more wasting time trying to get bubbles out the old way. These tools go under a bunch of different names from “vacuum refiller” to “coolant system refiller” but they all do the same thing.
This is another case where you want to spend some extra dough on a good kit. You’ll also need an air compressor capable of maintaining 90 psi for it with reviewers saying that a medium air compressor and tank will do the trick. Time for me to shop for compressors!
Do you know of a weird or unique but must-have tool that every wrencher should have? Do you want to see us put a type of tool to the test and see how it performs? Shoot me an email or drop it down in the comments!