Any A/C Experts?


RIP
06-06-2004, 07:43 PM
What would make my A/C work great sometimes and not at all at other times? Usually it works fine for 10 to 15 minutes or so, then blows hot air. Sometimes after starting up later it will work then die again or won't work at all. It's a 94 Camry with R134. Some facts:

1) The clutch appears to be engaged and turning when it's putting out hot air.
2) Both tubes coming out of the compressor are hot when it's not working - bad compressor? Why would it work sometimes?
3) I don't see bubbles at the sight glass. That plus the fact it works from time to time tells me it's got refrigerent.
4) I swapped the A/C MGN relay with the #3 FAN relay (same part #) - didn't help. (under the hood right side). I shook wire bundles/connectors - didn't help either.
5) The drive belt is in good shape and does't sqeal.

Are my conclusions correct? Are there any other relays etc. to check? I would hate to waste $400 on a new compressor and not fix it. What would you suggest?

Brian R.
06-06-2004, 10:49 PM
Most likely cause is insufficient Freon. No bubbles present in the sight glass can mean there is very little refrigerant. Check it for leaks if there is insufficient refrigerant.

Also, check the radiator for alot of crap in the fins, or something like paper blown in the front of it. That might be a possible cause.

jdo
06-07-2004, 10:42 AM
We have a 1996 Camry that is now in its third summer of doing the same thing. I must say that it has gotten progressively worse and this year I have no air. My husband replaced the switch with one from a junkyard Camry and it gave me air like I had when things started going bad. Just as you said it sometimes works and sometimes doesn't. when it works the air is cold so it is not a coolant problem. The ac will run for 30 secs, 10 mins, an hour, or a day and then nothing. There seems to be no rhyme or reason for this. We put a brand new switch in yesterday and it ran well for about 1 hour and then slowly went out.
What is the common denominator here? Anyone know? It is hot here in Savannah for this to be going on!!!!

bz2fx8
06-07-2004, 03:33 PM
I had the same issue with my 96 camry also. I had a neighbor that was a mechanic and helped figure the problem. As you said it had no leaks and the freon was fine. He evac the system and I replaced the Expansion Valve,which is located under the passanger dash, I also replced new o-rings. It has not failed ever since this was about 3 1/2 yrs agao. Good luck!

yotatechie04
06-07-2004, 04:52 PM
bz2fx8, which Expansion Valve are you speaking of, there are numerous ones in the Camry. There are at least four that I can think of that are located under the dash on the passenger side, and that's right off the top of my head. Where exactly is it located? I've had lots of people e-mail me with this problem, and I can't seem to pin point exactly what it is when they don't give sufficient detail. From all of the symptoms that everyone has mentioned to me, it points to the condensor, although this Expansion valve you're speaking of might be the probable cause. Get back to me and let me know...

RIP
06-08-2004, 10:05 PM
Most likely cause is insufficient Freon. No bubbles present in the sight glass can mean there is very little refrigerant. Check it for leaks if there is insufficient refrigerant.

Also, check the radiator for alot of crap in the fins, or something like paper blown in the front of it. That might be a possible cause.

OK. I serviced the A/C with one can of R134. Now the compressor cycles on/off every 3-5 seconds constantly. Is this an indication of over servicing? The condensor is clear of debrie. After talking to my daughter who drives the car she says the cooler outside it is the longer it would blow cool air. What's next?

Brian R.
06-09-2004, 02:22 AM
Could be the evaporator temperature sensor.
There is also a revolution detecting sensor and an a/c amplifier.

Honestly, I have never overserviced an a/c unit to know what the symptoms of overservicing are.

If the sight glass appearance hasn't changed, I would assume you are overcharged. If there are bubbles showing now, you are still undercharged and need more freon.

yotatechie04
06-09-2004, 06:29 AM
So Brian, you're saying that if there are bubbles that are showing in the A/C clutch window, then it needs more charge? I'm confused with all of this now. I've serviced quite a bit of A/C systems, and never really encountered a sign of over-service, whatever that may be.

Brian R.
06-09-2004, 09:16 AM
Yes, if there are bubbles in the sight glass, he is underfilled. I don't know how to determine if a system is overcharged, other than testing it with pressure gauges. Having too much freon above a certain amount will damage the compressor if it has to try compressing liquid freon because the system has no expansion room.

If he started off with a clear sight glass and the compressor is turning (engaged clutch) and intermittent cold air, it could mean that he has too little freon and some plugs of it are circulating and periodically being compressed - cooling the evaporator coils. It could also mean that one of many parts in the a/c system are bad and the freon charge is correct.

Now that he's added some freon, and it's changed in function (still not working correctly), he's either overfilled or still underfilled.

If he's underfilled, there are now probably bubbles in the sight glass and he can tell. Originally, he could have been so underfilled that there was not enough freon to make liquid to show bubbles in the sight glass. There could still be enough pressure to activate the pressure sensor and keep the compressor turning.

If he is overfilled (still no bubbles), I would allow some to evaporate by opening the valve on the low-pressure side until bubbles appear in the sight glass and then fill until the sight glass is clear again.

Alternatively, bring the car to a a/c shop and have them hook up a tester and figure out the condition of the system.

In all, if underfilled, he better check for leaks.

chuey11
06-09-2004, 10:29 AM
Interesting problem on your camry, let me point out a few things before you possibly overcharge your sys.
1. Compressor initially cycled before you added r134
2. both lines to compresoe were hot.
3. Sys cooled for 15min then took a dump.
4. Drive belt appears to be in good shape.
5. No bubbles in sight glass. (Lets start here.)
Dont rely on sight glass for evaluation of sys. open windows, closed windows, rpm, humidity, hi speed low speed electric condensor fan, compressor cut in cut out and a few other variables will affect what you see in sight glass. You need a set of gages to find out what your hi side pressure is. should be ambient * 2.2 to 2.5, # 1 problem with your sys. is both compressor lines are hot. Ive worked on a few hundres auto ac systems and i have never seen both comp lines hot. I would start looking for a restriction (feel and touch) an abrupt change in temp on hi and low side lines. do this when sys. goes from working good to blowing hot air.(whatch for moving parts) Moisture in sys. can cause intermitent operation. Yes there alot of things to look at I havent even got into the amplifier. Get gage reading when sys is working then again when sys takes a dump. repost...

yotatechie04
06-09-2004, 06:15 PM
Thanks for clearing that one up for me Brian...no more confusion now...I'm quite with it this time...:)

Brian R.
06-09-2004, 06:52 PM
chuey11 is right on.

RIP
06-10-2004, 12:32 AM
Good Lord! The flood gates have opened. I certainly do appreciate all the help. Unfortunately the car is 500 miles north of me in northern California now. Maybe thats a good thing. I'm going to take Brian's advice and have my daughter get it to a shop (like I should have done in the first place). I've got a van with front/rear a/c I've been nursing a leak on. Just been topping off the freon for two years now. I thought the car wouldn't be the headache it is. Time to punt and let a pro look at it. I'll let you know what happens. Cheers!

Brian R.
06-10-2004, 12:04 PM
Good luck

jdo
06-10-2004, 07:59 PM
Wow I'd say we had many replies to this. Seems to me that this is a Camry problem that many have dealt with. shortly after writing into this forum I found another possible suggestion and that is that the AC compressor clutch is slipping or the drive belt is loose. This was an answer to a 1995 Camry ac problem just like ours except they mentioned the indicator light blinking before the air went out.

It looks like here my hubby has decided on an ac person as well! One thing though he can speak about some of things to the mechanic.
Thanks all!

Grymloco
06-11-2004, 12:39 AM
you should look on ebay for a cigarette lighter fan and get it over with. fuck putting any of your unearned ebt card money into an a/c fix..
food stamps rule!

RIP
05-06-2005, 10:57 PM
Yahooooo! Had an A/C shop look at it today. They changed the expansion valve and all is well. Since I last posted (a year ago) it would only stay on a minute or two then die. Glad this headache is finally over. Thanks for the info. Cheers

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