Firestorm500

Quote: "This is making feel like a total noob. :banging:"

It's not you. This sort of crap happens to me all the time.

md21722

Right. Sometimes you just get a bad part.

Over time I've learned moving forward means moving cautiously and methodically. When acting in haste or not at all, costs can increase.

puredrive

there might have been a small leak on the AC manifold . Around the crimp, AC dye is lighting up under the black light.

This AM , I hook everything up. Torqued the A/C Low Pressure Service Valve Nut to 28 ft. lbs. as per spec and I am pulling vacuum now. If It does not hold vacuum. I would just cry

md21722

Does your A/C blow cold now?

puredrive

it's not holding vacuum. So I decided to take a break.


I could pump 1/2 a can of 134a and try to trace the leak. But I really don't know what else it could be.

Faulty part in the condenser, refrigerant line? Putting parts in is easy, but I'm at a loss. Just annoyed

md21722

It sounded like you changed everything. How big is the leak? Does it pull down vacuum and not hold it, or are you unable to hold vacuum overnight? If its a big enough leak you should be able to pump it up with nitrogen and hear it.

Thinking outside the box, have you checked the manifold hoses and ensured that the vacuum pump will produce the right vacuum? You are pulling vacuum with both the high and low pressure valves open?

If the condenser or evaporator are the issues there is either leak in assembly or at the o-ring/quick disconnect. Generally these get coated with refrigerant oil or Nylog on assembly, but even dry they should hold vacuum or pressure.

puredrive

How would I go about pumping it up with nitrogen ? Is this something readily available?

The pump will push vacuum till -29 with both valves open. Run the pump for 30-45 for my test. Close the valves and it will slowly leak out. Vacuum will not last 10-12 min.

I thought about the manifold hoses, these were bought from advance auto about 3 yrs ago. I could borrow a set from a friend, that could be a few days before I can get my hands on them.

md21722

I thought you had a new NAPA manifold hose assembly on there?

If you don't have a nitrogen cylinder and regulator its probably not worth the expense to buy it for this. You can buy both at welding/air supply shops, then do tank exchanges when you run low or empty, same as oxy/acetylene. Generally you don't want to use shop air because of oil and moisture in the lines.

Sometimes you will find systems that will hold pressure, but not vacuum, or the other way around.

I am guessing here, but I would think a pin hole leak in a part like the condenser or evaporator would lose vacuum much quicker than 10-12 minutes. If it were me, I'd pull all the lines apart, inspect the o-rings, r/r any that look torn or worn, coat them with refrigerant oil or Nylog, reassemble, and try another vacuum pull down.

puredrive

I meant AC manifold gauge set. I'll have access to a friends gauge soon.

Firestorm500

I would be looking real hard at the condenser next. They seem to go out more often than the evaporator. Thank goodness.

Try your UV light on the condenser. Fittings, fins, tubes. Everything.

puredrive

ok..the lines that lead into the evaporator (firewall) are ever so slightly scuff.

creating a small leak. will try to get a picture to see if anyone can can suggest a fix.

Firestorm500

If it is the actual evaporator lines, you're probably going to have to replace the evaporator.

md21722

The seal is between the o-ring and the manifold line. Sounds like you may only need to change the o-ring, lube it, and put it back together. If the line is damaged such that the o-ring won't seat correctly, then you have bigger problems.

Firestorm500

He said the line(s) are scuffed, causing a leak.

md21722

Yes, but in what way is the line scuffed that is causing the leak? Just because something doesn't look good doesn't mean its causing a leak. The evaporator side has o-rings and seals against the manifold lines which he just replaced.