Can you give me an idea of how long it should take to pull a vacuum on my AC system with an electric vacuum pump? I let mine run for ~20 minutes tonight and it only pulled ~5inches. I shut it down, locked it up, and I'll see if it remains the same by tomorrow morning. Should it take that long to pull a vacuum?

On a similar note, what is the best way to detect a leak in the system? I have a sniffer - should I go ahead and put in one can of refrigerant in the system and sniff out a leak?

Thanks,
M

 

What kind of pump is it? I have a 3cfm 2 stage and it will pull down to 30 inches pretty quick. If after 20 minutes you don't get a good vacuum you either have a leak or a bad pump. Put a can of 134 (I assume that's what you're using) in there and give it a sniff. If you can't find anything try injecting some dye. Also, if you have had the system opened you need to replace the filter drier and put the correct amount of the right type oil for your car back in before you re-assemble, vacuum, and charge.