Hi everyone. Long time Car Talk listener, first time engaging with the community. I know it’s a good one though which is why I decided to turn here first!
About three weeks ago I tried recharging my 2008 Ford Focus with one of those A/C Pro trigger hoses with the gauge. It filled up to about 20 psi then capped off and wouldn’t go any higher. Started out around 5 psi.
The AC was still blowing cold afterwards, though, so I decided to give it a few days and see how it did/when it would die again.
Lasts about a week till it starts blowing warm. I thought this meant it was leaking, so I bought a dye kit and injected it into the system. I searched high and low but never found any sign of a leak.
I started reading around, figured out the best method of recharging was vacuuming out the coolant and moisture first. I rented an OEM pump, ran it 35-40 minutes, then let it sit for another 35-40 minutes. Pressure stayed steady the whole time, exactly where it had been when the vacuum switched off.
No leak after all, right?
I then filled up the system again. Air starts blowing cold.
Next day, the air’s warm again.
I recognize there are a number of places I might’ve screwed up here. I know I should have added the R-134a by weight instead of going by the PSI but I didn’t have a scale, and I thought I could get away with it. Also my first time using the AC Pro I shut up the windows and doors halfway through, which is about when my gauge capped off at 20 psi. So when the vacuum held on my second attempt, and I ruled out a leak, I thought I simply screwed up the reading on my first attempt and put in far less refrigerant than I should’ve.
But then I realized even if I had added too little coolant, the air temperature should hold, correct? Even if a little coolant made the air blow a little cooler, it should remain a little cooler. Unless there’s a leak. Which there didn’t appear to be when I vacuumed it.
Did I not let it sit long enough? Is it possible for a leak to exist even if the vacuum holds?
Any help is much appreciated!