The Mitsubishi Pajero Owners Club®

[Metnav1]

Well I had a leak.

So I pressure tested with nitrogen at 250 PSI. No sign of a leak, no hissing anywhere.

I filled it up with gas, and dye. The tell tale bubbles where evident in the site glass 24 hours later. But no sign of dye anywhere.

A week later the AC quits; still no sign of dye.

I pressure tested again with nitrogen at 250 PSI; still no leaks evident.

I gassed and dyed the system again, and again 24 hours later the site glass showed significant bubbles.

5 days later the AC quit.

Suddenly the rear pipe that is usually the problem was covered in dye. The leak was underneath the foam insulator, and the foam absorbed the dye until it was soaked through.

I replaced the pipe; What a sod. I had to torch the connections and still ended up damaging the threads. I retapped the threads and finally got the pipe on.

I pressure checked it with nitrogen at 250 PSI, after 20 seconds I blew the connection on the larger pipe next to the replaced pipe.

I replaced the connector "O" ring and reconnected it. Pressure checked at 250 PSI. No problems.

I regassed the system, and hopefully it's fixed.

Is this the norm ?

[Google]

[Sam-F]

Leak can be hard to find at times
pressure testing with nitrogen at 250 PSI is very high I know the high pressure side will go this high when running but you are also charging the low pressure side with the nitrogen and 250 PSI can damage it
If a car is suspected of having a leak I charge with nitrogen to 100 PSI close the gauges and leave it for 30 mins then check the gauges again for any pressure drop if all seems ok I will then take the system into vacuum and close the gauges again for 15/20min then again check for lost on the vac gauge
I find the vacuum will show leaks the pressure will not and vice versa

[Metnav1]

Sam-F,
I used to use 100 PSI on the R12 systems, but since the new stuff has a smaller molecular structure (it's thinner and leaks more easily ), and requires higher pressure to obtain the same cooling level as R12, I feel 250 PSI is more likely to hiss for a small leak

I'm a bit impatient so I only leave the gauges for about 10 minutes.

I'm not an HVAC guy; I have worked on them, mostly industrial units in far away places, trying to keep essential electronic systems cooled.

I also work my own car systems, because decent HVAC guys are hard to find.

Keep up the good work, the world needs you; global warming is here to stay.