So I'm trying to refill my ac, but got stuck. What's the pressure suppose too be for the Hg vac well drawing vacuum thru the system? I've only got it to 20hg. Is it suppose to be 29hg or 30hg? If so what could be the problem of not going any further more from where I'm at on the garage.

 

Is your vacuum pump capable of pulling more than that? How old is it? Theoretically, you need to pull it down to darn near 30 for at least a minute. If you can't get it that far, you either have a leak, or the pump simply can't do it.

 

As mentioned, if you don't have a leak, the system should pull down to 29.5hg. On my vacuum pump, it has a provision to vent the oil in the pump. From time to time, I'll open that vent for a minute or two, then close it and have found that it helps the vacuum process pull a deeper vacuum.

 

Still need pump with the right oil in it and it's from harbor freight a 2.5 CFM vacuum pump. It's one line over from 20hg had it pumping for 30 minute's maybe little bit over. Now it's been 30 minute's and it's still holding the same pressure.

 

You may have a leak - here's one way to check for it -

 

​​​​​If theirs a leak in the engine gasket could that case the ac problems too or those two separate?

 

I heard a noise when I hooked the air pressure but sounded more like toward the exhaust manifold 🤷🏽

 

They are two separate systems. If you're hearing air near the exhaust manifold on the passenger side, there may be a leak in one of the lines/fittings over there. Try to work to narrow down where the leak is coming from, as noted in the video.

 

Elevation plays a role to. If you are way above sea level you can't get it to -30inhg.