A/C is overcharged? but blowing warm air...?

S

SurfXJSnow

NAXJA Forum User
Location
Charlottesville, VA
So, 2 summers ago i noticed my A/C was blowing air that was anything but "cool"... so i stopped at a local auto parts store and picked up one of those recharger bottles with the pressure guage attachment and filled it up to normal and i had cool air again. Then last summer i noticed it was blowing warm air again so i got another bottle (the same one) and charged it again. Nothing happened, still hot air. So i went through the whole summer with no A/C and just dealt with it. Now, im just plain sick of my ass sticking to my seats now that its getting warmer and want to get it blowing cool air again. So i got ANOTHER bottle today, hooked it up and much to my suprise the guage said my system was overcharged. I was in the RED which is the "WARNING" area. A/C was still blowing warm air so i decided to stick a screw driver down into the nozzle to try to relase some air. I let all the air out and nothing changed, still warm air. Hooked the bottle up again and with my A/C blasting inside I charged it again. Took only about ten seconds until the guage told me i was in the "WARNING" area again. A/C still not blowing cool air so i gave up. What could the problem be? Bad A/C compressor? FRANKZ!???? your the HVAC guy here. ANYTHING?

Thanks in advance! :worship:
 
Time to pay a shop for those special tools they have.
 
I'm 99% sure the lines need to be changed out becuase the diameter is different for the old lines that used freon vs. the new stuff. See a professional. :yap:

I also know that you have to completely bleed out the old stuff as well. :gonnablow
 
AC systems are sensitive to overcharging as much as undercharging and both can affect the vent temperature.

Don't know what year XJ you have, but my 97 only takes about 1.5 cans of 134a for a full charge.

If you don't know how much freon you have in the system, it's best to evacuate, then put a vacuum on the system to burn out all the moisture before charging the system.

It's also a good idea to replace the accumulator while the system is open.
 
Frank's in Moab!!! wish I was there 2.

Did you try turning the temp. knob to cold:D:D:D
 
It should have a pressure switch for high and low, if its too high it has a pressure relief valve. I have come across several vehicles with condensors that have plugged or "full of sealant/oil mixture" . I'd pull it apart and flush your whole system out. Start with the condensor,and replace the reciever drier ,and all the o-rings. then see a a/c equipt dude to do it properly,it needs a vacuum on it first!
 
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Jonathan,

Yeah, it's possible that you've over-charged the system, but that in itself isn't going to shut the system down.... It could, but not the only reason.

Since you were having problems early on with it not cooling - simply adding Freon/R134a isn't the fix all the time - it's not like the AC system uses it like an engine uses fuel....... you may have had a leak, or some other component had failed.

Other than a Freon leak, most failures are due to switches in the system or a bad clutch on the compressor.

First, when you switch the AC on, does the AC compressor clutch snap and engage? Does it stay engaged, or does it disengage shortly after and never engages again while running? If it engages once, then won't engage again while the engine is running, the pressure sensor may be shutting it down due to the over-pressure.

Does your auxiliary fan at the radiator turn on when you move the dash switch to AC? It should be on at all times that the AC is on.

If your AC compressor clutch is cycling on/off, on/off rapidly, then it's likely that either you have low Freon pressure, or the pressure sensor is bad.

Do the aluminum AC lines that go into the firewall get cold at all? If not, then the Freon isn't getting compressed.

If the lines are cold, but warm air is still coming out of the vents, you have a problem with the blend doors in the heater/AC box behind the dash - a blend door is staying open for air flow from the heater core and closed from the AC core.

The only other thing I can think of is a clogged up condenser (cooling fins full of bugs, leaves, mud, etc....) I've only seen this be a problem on rigs that play in the mud, but in other vehicles I've also seen mouse nests and mud wasp hives built between the condenser and radiator causing overheating issues with both the AC and engine.......

Check these things and let us know.
 
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YELLAHEEP said:
Jonathan,

Yeah, it's possible that you've over-charged the system, but that in itself isn't going to shut the system down.... It could, but not the only reason.

Since you were having problems early on with it not cooling - simply adding Freon/R134a isn't the fix all the time - it's not like the AC system uses it like an engine uses fuel....... you may have had a leak, or some other component had failed.

Other than a Freon leak, most failures are due to switches in the system or a bad clutch on the compressor.

First, when you switch the AC on, does the AC compressor clutch snap and engage? Does it stay engaged, or does it disengage shortly after and never engages again while running? If it engages once, then won't engage again while the engine is running, the pressure sensor may be shutting it down due to the over-pressure.

Does your auxiliary fan at the radiator turn on when you move the dash switch to AC? It should be on at all times that the AC is on.

If your AC compressor clutch is cycling on/off, on/off rapidly, then it's likely that either you have low Freon pressure, or the pressure sensor is bad.

Do the aluminum AC lines that go into the firewall get cold at all? If not, then the Freon isn't getting compressed.

If the lines are cold, but warm air is still coming out of the vents, you have a problem with the blend doors in the heater/AC box behind the dash - a blend door is staying open for air flow from the heater core and closed from the AC core.

The only other thing I can think of is a clogged up condenser (cooling fins full of bugs, leaves, mud, etc....) I've only seen this be a problem on rigs that play in the mud, but in other vehicles I've also seen mouse nests and mud wasp hives built between the condenser and radiator causing overheating issues with both the AC and engine.......

Check these things and let us know.
Click to expand...

Ill try to explain whats going on to the best of my knowledge, for i know NOTHING about A/C...

One thing i noticed is that the fan up near the radiator comes on for about 8 seconds, then stops, then comes on again for 8 seconds, then stops.... it does this constantly when the engine is running and the A/C is on full blast. When I have the pressure guage hooked up to the aluminum tube it seems to fluxuate when the fan comes on an off. When the fan is on, the guage gradually climbs until its reached the warning area on the guage, then when the fan turns off it drops back to the green area which says i have a low charge. It seemed like the more i charged it, the longer the fan would stay on before it shut off again... Then, towards the end after filling, then releasing pressure through the nozzle, the fan just stopped coming on all together. This is when i stopped for fear of messing something up beyond repair and asking for help. BTW, its a 98. a little under 150K on the clock.
 
Again....... you're getting all caught up on the pressures and such. You didn't answer any of my other questions about the system functions.

The pressures are going to fluctuate....... low pressure when the compressor clutch isn't engaged, high pressure when it's compressing. Since you say you can see pressure changes, that tells me that the Freon is being cycled and the compressor is working.

The aux fan will likely cycle as well - that shouldn't be of concern. As long as it's coming on - that tells me one of the two switches in the system is working.

Are any of the aluminum tubes near the firewall getting cold at all? If the compressor clutch is engaging and it's compressing, the aux fan is coming on, but both compressor and clutch are cycling frequently, that could possibly indicate a blockage - there is a filter in the system and if it's clogged, it's gonna keep things from flowing.
 
I have same problems.
compressor is cycling.
aluminum tube into the evaporator is cold, running through the firewall.

from time to time (maybe every couple months) the vents get stuck on the defrost outlets - so i know i have a vacuum problem.

my next question is -
where do i physically locate the blending vent that will allow cold air to come out ?

do i have to tear the whole dash out like some of these other guys have done ?
 
Here is way to find the leak. Take can of stop leak with red dye in it and hook it up with engine off. It will pressurize the system and you should be able to find the leak. My guess is you have pin hole in your condenser. They around 100 bucks for a new one off Ebay. I just got a new one for the Lincoln today off Rockauto.com. Wife was complaining about the Lincoln not cooling. So I used stop leak and found the hole. I could see it and figured it was the problem just confirmed it when I could hear hissing out there. Stop leak can be bought at Walmart.
 
Stang5lgt said:
Here is way to find the leak. Take can of stop leak with red dye in it and hook it up with engine off. It will pressurize the system and you should be able to find the leak. My guess is you have pin hole in your condenser. They around 100 bucks for a new one off Ebay. I just got a new one for the Lincoln today off Rockauto.com. Wife was complaining about the Lincoln not cooling. So I used stop leak and found the hole. I could see it and figured it was the problem just confirmed it when I could hear hissing out there. Stop leak can be bought at Walmart.
Click to expand...

Please, do not do that! AC stop leak will trash a shop's AC machine when it's hooked to the system. Of course, it's your right to use any product you want on your car, but please mention that the product was used when brought in for future AC service.

Regardless of that aspect, stop leak doesn't exactly help thermal conductivity and will hinder the system's performance once it's sealed up.

Anybody with a leak in Nor Co, you're welcome to stop by my work and borrow my leak tester (in the parking lot)
 
JJacobs said:
Please, do not do that! AC stop leak will trash a shop's AC machine when it's hooked to the system. Of course, it's your right to use any product you want on your car, but please mention that the product was used when brought in for future AC service.

Regardless of that aspect, stop leak doesn't exactly help thermal conductivity and will hinder the system's performance once it's sealed up.

Anybody with a leak in Nor Co, you're welcome to stop by my work and borrow my leak tester (in the parking lot)
Click to expand...
I was only using it to find the leak. And the only time my cars ever go in to a shop is to get tires mounted or alignment done. Otherwise I don't trust any shop. Last time one my cars was in a shop 15 years ago. When I was eighteen. After seeing the bill I made sure I learned how to fix my own junk.
 
Stang5lgt said:
I was only using it to find the leak. And the only time my cars ever go in to a shop is to get tires mounted or alignment done. Otherwise I don't trust any shop. Last time one my cars was in a shop 15 years ago. When I was eighteen. After seeing the bill I made sure I learned how to fix my own junk.
Click to expand...

You might consider that most any shop you take a car to would find an AC leak without damaging the system's efficiency. Maybe you shouldn't trust yourself.

:)
 
JJacobs said:
You might consider that most any shop you take a car to would find an AC leak without damaging the system's efficiency. Maybe you shouldn't trust yourself.

:)
Click to expand...
I trust myself before I would ever trust you. But I know how you like to get on here and insult people so thanks I feel good I have been chosen. Coming from non paying member I love it. :D

Funny part is if that stuff is so bad then why do they sell it? I would think they would have so many law suits cause peoples AC stop working that it would off the shelf. But funny thing I have seen it on the shelf for over 8 years. So maybe you and all your mechanic buddies should get together and start class action law suit to stop the selling of stop leak. You would be hero and you could sleep at night knowing you saved the world. :yelclap:

But you would rather call anyone who uses it dumb...

This is what I think of Ford techs. I bought a brand new 04 F150 FX4 38k dollar truck. Got a great deal on it. Never took to dealer once it left the show room floor. My dad on the other hand took his brand new F350 FX4 Dually PSD 6.0 to the dealer cause it was loosing coolant. They told him it was because he was over filling cause they are so smart. So he tells me about it a month later. I said maybe you have blown head gasket cause I am so dumb. He said Ford tech told me I was just over filling it and it was blowing out. So he takes back a second time to a another Ford dealer. Tell him same deal hey man stop over filling it cause again they are so smart. Every time he goes there they charge 100 bucks for deductible. So final he bitches a third time after 7k miles. They say they will run some tests turns out the dumb non Ford tech me was right. But by this time the head and motor are so so pitted that they have to replace the motor. So replace it after having it a week my dad is 700 miles from home was stuck until the truck was fixed. This story is only getting started so you might wanna get some popcorn.

So he heads back WV and next day after getting home he goes to try and start the truck nothing. Huh only had the truck one day and it doesn't wanna start after the awesome Ford tech had fixed it. So he calls me the dumb non Ford tech. And I tell him to check the starter wire and see if it tight. He checks and tightens it VAROOOM! It lives cause the dumb non Ford tech guy. We will just call him DNFTG from non on getting tired of typing it. So he another year goes by and truck looses a water pump cause the FT didn't tighten the bolts good enough. Truck only has 50k by this time. A few months later my dads wife has it break down in traffic he tells DNFTG what I happens and DNFTG tells him sounds like you engine is toast. They take it to Ford dealer and FT guy says hey your engine is done. So he goes to check on the truck few days later and truck is sitting outside with no hood and windows rolled down while it raining cause FT guys know best. They get the truck back together and tell him he will not have anymore problems. Now that is @ss hole is large enough to drive a bus through cause the FT guys kept stickin it to him. They were nice enough to use lube since it was handy. So what does he do drives to Toyota dealer and has a new Toyota now. Thanks to the awesome FT guys. So I will take my chances on myself. I can't afford those awesome FT guys. THE END.
 
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