I own a 1995 Mark VIII and I was wondering if the tank by the passengerside firewall is where I am suppose to add the freon. I connected my hose there and I am getting a reading of 100 psi (red zone). Is this safe? Am I suppose to add freon to that connector by the tank near the firewall or is that the wrong spot? If it is the right spot do I have to release some pressure in order to add the freon it needs?
I had the same problem 2 month ago and my mechanic added 3 cans but none had stop leak in them. The air is coming out hot again. The pump is working. How many cans does it take if it is empty? If I had to drop the pressure how should I go about it?
:F

That is the correct place to fill it, however your pressure is too high for some reason. You need it checked out, if you add more you will only hurt the system more. Are you getting the readings while the car is off, or on with the A/C blowing max? I believe you need a special $2500 machine that vacuums out the old stuff.

check that pressure with the a/c running,should be like 30-50 psi

the amount you need with completely empty system is printed on a tag under the hood.

Did your mech. look for a leak.
because the freon is getting expensive and fixing the leak might not cost much if you only need new oring.


mike

I had the air on automatic but not on full blast. Am I suppose to have it on full blast in order to fill it or take a reading? My mechanic didn't look for a leak. I will look under the hood for that information. If the system is leaking why would it have so much pressure in the tank? One would think the pressure would drop if it had a leak. Thanks guys! I really appreciate this. Any idea on how to reduce pressure so I don't kill myself when I try to fill it?
Eric :F

I think the last thing the system needs is more freon, you could have a blockage in the system that is creating the high pressure. Too much freon can cause way more harm than too little; to the sytem and yourself. You may not have a leak, because again the high pressure is the culprit for it not blowing cold. I think you need to have 'another' mechanic look at it. Good luck...

I was checking it wrong. When I checked it with the airconditioner on high the reading was between 25-40psi. I noticed that when I opened the can up so more freon would go in faster the pressure gauge would soar to 90psi. I let out the freon out very slowly which kept the gauge pressure within the normal range. The car is now cool, very cool! Thanks for the advise:F :wrench :invasion:

Good to hear!

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I was checking it wrong. When I checked it with the airconditioner on high the reading was between 25-40psi. I noticed that when I opened the can up so more freon would go in faster the pressure gauge would soar to 90psi. I let out the freon out very slowly which kept the gauge pressure within the normal range. The car is now cool, very cool! Thanks for the advise



It would soar to 90 because you were letting the pressure out of the can through the gauge. I will have to get the book out.......But I could have sworn the operating pressure on the mark A/C system, is 55PSI on the Low side, and 375-400 Psi on the High. It's been a couple of months since I worked on either of the marks, so Ill have to look to be sure.


Did you put any oil in the system before you charged it? If not, you could be looking at a new compressor.

It would soar to 90 because you were letting the pressure out of the can through the gauge. I will have to get the book out.......But I could have sworn the operating pressure on the mark A/C system, is 55PSI on the Low side, and 375-400 Psi on the High. It's been a couple of months since I worked on either of the marks, so Ill have to look to be sure.


Did you put any oil in the system before you charged it? If not, you could be looking at a new compressor.


55 psi on low side is possibke,little high,but ok.
375-400,seems too high ,i think more like 250-300 max sounds right.

if you hear any compressor noise/rattle. anything loud enogh to hear over engine running, you should add a can of oil charge.

mike

Guys,

Is what I am reading here ALSO for the 93 Mark VIII. Is the low side connector up next to the firewall on the passenger side?

newviiiowner
David Crawford
Henderson, KY :L

All signs point to yes!