UNCatTech

I have a 1999 TL. The AC starts off ok, then it slowly gets warmer until it is probably only about 78 degrees. I have replaced the low pressure switch and vacumed the system and recharged it. When I measure the pressure it bearly gets to 25PSI on the low pressure side. I have put the 22oz of 134a in it, so I don't believe it is a charge issue. I removed the cabin filters the other day and they were very dirty, but it isn't any better now. Does anyone have an idea what my issue might be?

hANDYcaptd

iTrader: (5)

Is your compressor running?

01tl4tl

Has it worked right at all since you did a vac and recharge?
how long ago was that? and why - what broke before that and how long did the system sit broken

Could be an issue in the filling procedure caused this- I always suspect the last work done on the car

do some basic testing--feel the temp between 2 hoses coming from firewall to ac - how much differance in temp --none or a little?
High pressure side reading?
25 is good on the low side- ambient temperature dependant
One of the cans had 2 oz oil in it? not, each of the cans had oil

Ac should blow ~40 degrees cooler than outside air, to a min of about 38-40 F measured at center vent in console
Keep car doors open while filling freon- so ac stays On working full time
and have small box fan blowing extra air into radiator while working

When its hot out its going to be less effective~ but losing its cold abilty while driving and then be good again the next day-thats got me stumped right now

Who is our ac guru?

jdjohn84

Sounds like typical low pressure problem. "barely gets to 25psi" is not enough. S/b at least 30. I say add more R134a.

01tl4tl

if it was just low, it would not get cold then get warm- it would never get cold enough

when adding freon, the low side pressure reading will go down as it nears full- the acceptable area on my guage is 20-40 iirc

do NOT add more freon without knowing high side reading- you can literally blow up the compressor!
If label says 22 oz and you put that much in- STOP and find out where it stops circulating

Is the metal tube under evap core- pass side under dash- is that iced over?
and the condensation drain tube for the ac from pass side to outside=-that drain is clear

UNCatTech

Ok, to start the summer it would work but stop working in stop and go traffic. I talked to someone who works on car AC and they said that it sounded like the low pressure switch. I changed that. Since then it has worked then slowly gotten hotter.

It is probably blowing low 50s when working well.

I used 134a from a can with oil in it, approx 18oz. Then I filled it from a can of straight 134A.

I cannot check the high side pressure, my guage is broken.

I am my own AC guy. My dad owns an industrial AC service company, so I know a little, since I grew up helping him.

I'm sort of thinking that it might be over charged. I was wondering if overcharging could cause the low side to be lower than it should be.

UNCatTech

The tube is not freezing.
Condensation is draining.

reese8789

iTrader: (1)

Make sure your fans are coming on, that could be the problem . If the a.c. is cold when your driving then warms when your just idleing the fan is probably not working.

friesm2000

iTrader: (4)

i was going to say that first also , but yeah sounds like a lack of airflow especially sitting


so how well does it work OP when you are cruising along the highway

btw OP but it does not sound like you know too much about A/C, cause you should know it would need airflow over the condenser in order to work effectively

01tl4tl

commercial ac background is not the same as car ac experience
Yes overfilling can take the pressure reading to low
Many parts stores will loan tools including ac guages

01tl4tl

passenger side fan should be ON with ac compressor On

UNCatTech

Assume a lot??

I stated that I changed the filters because of air flow.

It has air flow and the fans are running.

I would be willing to take a test against you to see how little I know about AC. You are assuming that I didn't check to see if there was air flow so that means that I don't know what I'm doing?

Who says something stupid like that?

Do I need to tell you everything I have done? Sorry if I didn't feel the need to write a 6 page esay on what I have done so far.

UNCatTech

Thanks. I purchased some new guages. What should the high side reading be? Someone told me that it should be around 2.5*outside temp, is this true?

And yes I know that commercial ac isn't the same, that is why I am looking for information from people who probably know more than I do.

But the basic of heat transfer and the process of compression and expansion are pretty much the same.

TLer trash

I've seen a few clutch coils fade away as they heat up. Still had power to the coil, but it wouldn't engage the clutch. I was able to get it to happen just by letting the ac run at idle for 10 minutes or so. Just to be clear, BOTH fans should come on whenever ac compressor is on.

friesm2000

iTrader: (4)

airflow over the condensor (outside) not the evaporator (inside), so get your terms correct first , and never mentioned the evaporator in my post

UNCatTech

Why don't you just stop posting on this thread?

I'm looking for help not some guy who assumes too much and makes comments about my intelligence.

If I forgot to say, I will say it not. The fan is working.

Guess what they use the same terms for a condensor and evaporator coil in a home ac also.

Since you obviously are here to cause problems, could you please just avoid anything that I post and I will do the same for you.

To everyone else, thanks for the help.

UNCatTech

You should also read beyond the first line. I stated in that same post that the "FanS" are running. I assumed someone as brilliant as you would know where the fan"S" are.

I have enough issues with my car, I really don't need someone like you trying to help.

mnm

Question, does the suction pressure stay at 25 psi the whole time the compressor is running? When/if the low pressure switch cycles the compressor off does the suction pressure rise quickly? Assuming you have the correct amount of refrigerant installed, I would say it sounds like a partially stuck TXV. I have had that experience myself on a couple of cars.

rcb2000

so in otherwords your just guessing on how much freon and oil is in the the system since your just opening and closing a can and did not measure the proper amount oil or freon nor did you heat up the freon and forced it in either like it has to be done.

Once you evacuate the system you cannot draw it back in with the compressor running and feeding the freon through the low side of the system. So stick with home A/C and take your car to a professional that knows what the hell they are doing because you don't have a clue how an automotive A/C system works. I've learned enough watching and doing A/C work for my Dad at his shop to know your in left field.

friesm2000

iTrader: (4)

thank you, i knew i was not alone

UNCatTech

I believe this is the problem. Do you know where I can find any information on changing it?

UNCatTech

No you are not alone. Just another ass who assumes to much.

I have a digital scale and I measured in the remaining 4 oz, so I have exactly 22 oz, which is in the range on the label on the car.

I love you know it alls. Who can take a statement on a message board and go wild on what I did and didn't do.

By the way. I have a masters degree from GA Tech. I would be glad to talk engineering or CS with you anytime. Since you're so smart try reading between the lines there.

And as always thanks to those who actually tried to help me. I wish there was a way to get rid of those who only want to assume they know exactly what I did and didn't do.

UNCatTech

By the way, you cannot start the compressor while under a vacuum, it has a low pressure switch which will keep it from starting. But of course you knew that, since you are smart enough to know what I did even though I didn't tell you every detail.

So you keep working for your dad in his shop.

friesm2000

iTrader: (4)

first of all, how accurate is your scale

then second did you add any of the refrigerant in the lines them selves (the gauge's hoses), and since it sounds like you did it twice, you might have to add it up twice

third, you cannot just do a weight and expect it to be good, gotta get the pressures correct, and the weights are only a starting point fyi (some cars like it on the lower side of the weight range, then others like it on the higher side; the reason for giving a range (also helps compensate for any inaccuracies that your scale may have also)

and forth, the thing operates on the same basic principle as household a/c systems, just different pressures (which are quite easy to look up tyvm, especially with being on the internet), and smaller components, and the compressor happens to be driven by a gas motor instead of a electric motor

mnm

Helms has online info for $10 a day. Never used it myself, so I can't vouch for how complete the info is but I would assume it to be accurate. Caution: Changing out a TXV is a big job on cars. The refrigerant should be recovered, the dash has to come apart to get to the valve, and proper vacuum pulled and then the system has to be recharged. Not a quick fix. I changed out a valve on my 96 Lexus ES300 a few years ago and it took several hours with the proper tools equipment and the factory service manual. Good luck.

rcb2000

what an arrogant ass hole you are. Too bad your so damn smart you got it fixed... Not .....dick head

totaledTL

Uh-oh...

friesm2000

iTrader: (4)

yes the system has to be recovered and such on ALL cars, so no argument there

but on some cars it is actually quite easy to do, cause you can get at it from the engine bay and such, but no such deal on our cars , dash has to come apart to get to it (and the majority of the other cars out there too), so yeah it is quite a BIG job

LMFAO

UNCatTech

Thank you. That is what I came to this site for.

UNCatTech

Thanks. My dad has several recovery units. I have talked to several people and I realize how big a job this is, but Acura wants $800 to change it, so it might be worth it. I'm still debating. My biggest issue is that I don't have a mechanic that I trust and can just take the car to.

UNCatTech

Quote:

Originally Posted by rcb2000

what an arrogant ass hole you are. Too bad your so damn smart you got it fixed... Not .....dick head

Thanks, from you I consider this a compliment.

I’m sure you don’t care, but I am going to explain myself.

When I came to this site I was looking for assistance. I knew that I wasn’t an expert, that is why I was looking for assistance. Several posters here have been very helpful, but one poster decided to tell me that I didn’t know enough about AC, because I didn’t state that there was air flow.
This irritated me because, he assumed this this. I knew that there needed to be air flow. I just didn't state it outright. It is hard when you are typing out the description to determine what information is helpful and what to leave out. For example I really didn’t see the need to tell everyone the car was running, I assumed that most would take that as a given. Same for the air flow.

Then you came along and seemed to only want to agree with the other poster. Your chivalry is impressive. But you also assumed. You assumed that I didn’t know how to add refrigerant. Not because you actually knew how I added, but because I didn't give every minute detail of how I added it. You were wrong. I do know how to add refrigerant. Personally I believe this probably puts you in the same category that you are putting me into. (Arrogant)
It was really funny that you made a mistake in your post also, (“Once you evacuate the system you cannot draw it back in with the compressor running” Especially since you cannot run a compressor with under a vacuum, unless, of course, you jump out the low pressure switch), since you were telling me how dumb I was.

Anyway. I’m not really that arrogant. I understand that I am not an expert, that’s why I was asking for help. What I didn’t understand what why other posters needed to tell me that I didn’t know enough. If you didn’t want to help or add anything to the post why didn’t you just move on???

Friesman2000, thanks for the help. Also sorry, I probably overreacted to the original post.

Rbc2000, you should realize that an arrogant asshole such as I, doesn’t care what you think.

To all, thanks for the help. Have a nice day.

friesm2000

iTrader: (4)

, and NP

but just know that we will get snipy right back at you, if you start being pissy towards us

Souljah

Matt,

rcb2000

Lets see, members point out things you have over looked or neglected to postn for what ever reason, Arrogant asshole comes to mind for me, so then you chastize them and call them stupid and to stop posting on your oh might thread. FU asswipe

TLer trash

First off, 25 psi on the low side is fine. The low end of honda's temp chart goes as low as 15 psi at 85 degrees F. I've had several cars in the past week that cooled fine and were in the 20 to 30 psi range; one stayed around 10. What's going on with the readings when it gets warm? A stuck expansion valve will usually cause a vacuum on the low side. If the clutch gives up, the pressures will equalize. There is an evap temp sensor to check too, but I,d have to look it up to get more specific. If your pressure stays around 25psi, is the temp door working? Is the water control valve staying open allowing excess heat inside the car?

UNCatTech

It was losing pressure to the point of a vacuum on the low side. I would turn it off so that it could stabilize.

After a few days of thinking about it and reading. I decided that I didn't want to risk making a mistake in changing the expansion valve, so I took it to a "Professional"

He checked it out and said it was the expansion valve. They replaced it and it is now working great.

Just out of curiosity (SP?) I asked about the amount of 134a. He said that the charge was ok. (So maybe I'm not completely dumb).

Anyway. Thanks for the help. I really learned a lot while reading about car AC and working on this one.

Sorry I was a butt at times. I'm not sure why some times I seem to take things very hard and respond negativly, while other times things will just roll off. Maybe I'm bipolar or something.

rbc2000 is my favorite poster. I guess you will always believe that I am an ass, I'm sorry that I gave you that opinion. Maybe in the future I will have another problem and when I post I will not offend anyone.

Now I have to change the wheel seal on my Expedition. Anyone done that? Guess I will find a Ford site now.

I have learned my lesson. I will be nice on the ford site.

Honestly it had to be the heat that made me be such a butt. Heat and bad traffic drive me crazy.

Thanks all.

friesm2000

iTrader: (4)

don't forget to change the blinker fluid too