GM Repair Problems? Ask GM Repair Expert Now.
What I do is charge it and use an electronic sniffer. Other techs that have dry nitrogen charge the system to 175 psi and use an electronic ear to listen for escaping gas or a gross leak they use soap on the joints.
Do you have the gauge set on both ports or is one port open?
Ok, when you waited you closed the gauge valves?
Ok, that is correct. You have a leak, O rings were basted with a little oil? All you can do at this point is look for the leak. Either from a fitting so take one off at a time and put the cap on that valve then pull the vacuum. Do the same with the other one if it still leaks. Make sure the hoses are tight on the fittings and on the gauge set.
The quick couplers are checked by removing the one and capping the port. See if the leak is better, if it is you know that one is leaking. If no better pull the other one off and pull a vacuum through the one you pulled off first.
When you have only the red hose on you only have the low resolution gauge to look at so it is hard to see a leak. With the blue hose on you have the high res gauge. Start by removing the high or red side and capping the port.
I hope it is in the connection otherwise you need a sniffer or you have to charge the system with dye and run it long enough to find the leak. It is wasteful if you can't recover the system.
You should not see any liquid, the point of pulling a vacuum is to cause any moisture or refrigerant to evaporate and leave the system.
Maybe someone got oil in there?
It could but you hung them from the hood latch? Then I don't know what would be in there except oil. You can try removing the yellow hose a squirt some brake clean in there, let it sit for 2 minutes then vacuum. Any liquid should be gone then.
Ok, let me know what happens, it is tough chasing a leak without a sniffer.
Good with the blue you can see the vacuum better. To be sure I would see how long it holds the vacuum. an hour would be good. If it does not rise go ahead and charge the system.
If you got 30 minutes out of it then you should be good. Charge it up and see what you get for temps after 15 minutes running it.
Let me know what I can do to help