Regarding this product: Astro Pneumatic Item # 78585 Universal Radiator Pressure Tester & Vacuum Type Cooling System Kit

https://www.astrotools.com/pro...-cooling-system-kit/

I called Astro Pneumatic Tech Support asking them how much air this kit needs to run, specifically for pulling a vacuum on an automobile cooling system using the venturi attachment from this kit that attaches to the filler neck of a radiator. They said they didn't know. I told them their documents don't specify, they looked as well, and admitted that their own documentation doesn't specify. I understand that Astro is an importer and marketer/distributor so they don't actually manufacture a damn thing, but the quality of this kit is pretty good for a driveway duffer.

So my question to you guys, particularly current and former vehicle mechanics, motorheads, and racers, can you tell just by looking at this bad boy if a small compressor rated for 6.5 CFM @ 90 PSI could run this thing ? If I was pro in a shop with system wide shop air it wouldn't be an issue, but I don't run a large tank in my home garage. I guess their target market is pro shops, so it makes sense that the question would be irrelevant from their viewpoint.

So anyway I like this kit but I can't use it wouldn't be able to evacuate one atmosphere from a standard automobile or light truck cooling system using a small Makita air compressor rated for 6.5 CMF @ 90 psi.

Any thoughts much appreciated if you think it would work. Yes but maybe slower, or worse not at all. A big compressor isn't in my future, but I'd love to pull a vacuum on a cooling system for refilling. Some systems can't ever be completely burped without some vacuum procedure.

90 psi should be fine.
It's regulated much lower.
Pulling a vacuum for an extended period will work the crap out of the compressor.
May work better with another tank plumbed in for more air volume.

The ones we have at work take about 5 minutes to pull in 12 gallons with full on shop air.
Not full pressure at the valves though, 20 psi for pressure and the vacuum has a restricted exhaust, not much pressure coming out.

I should add.
The connection is on the bottom of the system I mess with.
I vacuum coolant out and pressurize the tank to blow it back in, fill from the bottom up.
Same for clutches and stuff, bottom up.

We have the smaller ones like the one linked linked also but don't use those to drain and fill.
Handy for pulling a vacuum and removing sensors and such without draining a bunch out.

I have a 1 1/2 HP small Craftsman roll around with IIRC a 4 gallon tank. Note it's about 25 years old and my memory has not been improving with age so it may be a 6 gallon tank.

I also have a Ford Fiesta ST which requires vacuum filling the cooling system. Once I have everything hooked up and the overflow port blocked closed it takes about 1 or 2 minutes to see full vacuum on the gage. Switch the valves over to fill and that system will drain 2 gallons of AF from the bucket in perhaps 45 seconds. If all you are doing is topping up the cooling system you may only need 5 or 10 seconds to bring the system up to full.

My conclusion that a small pancake compressor for a nail gun and the like will do just fine. However the key is to know exactly how to make your cooling system 100% vacuum tight. In my case the rubber stopper that seals the filler neck did NOT seal the overflow port. Getting that sealed requires lifting the tank from it's mount and putting a piece of electrical tape over the port on the bottom of the tank. If you find that you cannot pull a vacuum then start looking for the overflow port for the reservoir tank.

quote:

Originally posted by powermad:
90 psi should be fine.
It's regulated much lower.
Pulling a vacuum for an extended period will work the crap out of the compressor.
May work better with another tank plumbed in for more air volume.

The ones we have at work take about 5 minutes to pull in 12 gallons with full on shop air.
Not full pressure at the valves though, 20 psi for pressure and the vacuum has a restricted exhaust, not much pressure coming out.

Your physics is a little over my head. So is the bottom line a yes, or more of a maybe for this makita air compressor I linked to in the first post ?

It would be like opening the tank drain valve just a bit and running the compressor.
The compressor will pretty much run constantly for however long you are pulling a vacuum.

Yours sounds about like the one I have for filling tires and such with a small tank.

If I was to use it for coolant I would get auxiliary tank so the compressor keeps up a bit better.
https://www.amazon.com/Torin-P...gid=pla-568938142979
Little units don't like to be constantly ran but once in a blue moon should be fine.