Using vacuum tool to fill a cooling system 

Thank you, and I have a ton of stuff planned, so stay tuned!

It would pull the coolant from the engine, you could catch it at the air output hose but I guess its way less messy to just drain it. If it's clean just fill it back.

No, you want to keep that closed or the vacuum will not build up enough. Thanks for watching!

@@AutoScholarwithMrB that makes sense ! Thanks for your reply

Hi, firstly great tool & video, my only question is that if this is done with the heater core in the closed position(cold) wouldn't this have the potential to create an air pocket once the heater core is put into the open position(hot)? Surely if the heater core is open(hot position) & the system is sealed the tool would also be good enough to also pull the vacuum through the heater core & fill it as well? Also my thoughts on anthor comment where one of your subscribers had the issue of using the tool on a car with an air lock on a full system, do u think that it would work buy having the over flow tube flowing back into the filerl bottle/container (with coolant in it)& cycling the coolant through in this manner(i have also had success with getting air locks out of cooling systems with a radiator pressure tester provided the system has bled points in the system) appreciate your thoughts on my comments, I'm a new subscriber (today) & give u a big thumbs up on your videos(I've watched a quiet a few today)they are very informative & easy to understand.....keep up the good work.

With this process it doesn’t matter because it vacuums the entire system, which includes both sides of the thermostat.

@@AutoScholarwithMrB thanks man! I will make the process soon!

0 psi is sea level air pressure. A vacuum is negative psi so you want to be going to -30. When you open the valves and let air in the number rises from -30 to 0. If your pump cannot draw enough air to go below -5, as in drop further towards -30 you need a bigger pump.

@@DuncanManutz Thanks for the response. I guess I worded my previous comment incorrectly. On all of my vehicles, the vacuum gets to -25 to -26 and holds there and I believe in the directions and many other videos says that is about where it should be. Nothing more. Upon FILLING, the pressure drops as fluid is sucked up. The problem I am having is that the fluid stops sucking when the gauge reaches around -4 or so; never quite getting to zero. I have used this tool several times now, on multiple vehicles. Only once was I able to completely get down to 0 during the refill process. on several occasions I forgot to purge the air from the fill tube and I used the tool a few hours ago making sure to purge. Same issue, got to about -4 before the filling stopped. Any ideas? It's extremely frustrating because while close, all of the air isn't completely bled.

Most thermostats have a small bleed hole to allow a small amount of coolant to flow past it even when it's closed(this is done so that cooling system components don't get thermal shock once the thermostat does open)

@@petergoz7453 Hi, I have a 2016 Volvo XC90 T6 which is hard to drain the coolant for maintenance purposes. Can I use this to drain or suction the coolant out and fill? Appreciate very much your help.

This would be good to fill & bleed the cooling system but i think its no good to remove the coolant, best remove the lower radiator hose, & if u can find the coolant plug in the engine block(some are hard to find & get to so i only do it if it's accessable)

@@serge1060 not really good to drain but more suitable for filling & bleeding

Never had an issue, it will settle at the top

If everything is leak free, indefinitely.

@@AutoScholarwithMrB it would hold 27 for 5 min and then it will slowly go down to 26

@@wdsanchez5 you are probably ok.

Most systems only are designed to hold 18 psi max so losing 1 lb is no big deal.