AC Intermittent, Can't we solve this? - Toyota Nation Forum : Toyota Car and Truck Forums

Landseer · 08-01-2007, 12:41 AM

Have spent the last 3 hours searching for answers online.

At least 15 people have reported the same problem on AC forums, toyota forums, general car repair forums --- and all answers are vague / useless.

94 Camry. Extremely cold air sometimes; no cooling other times. AC button on. Compressor engaged. System charged.

Have noted that metal tubing in/out of compressor is very, very hot when the compressor is engaged but not providing cold air.

What is going on with this POS? Has anybody faced this issue and actually solved it? Help.

dc_98_cam · 08-01-2007, 12:45 AM

If you have moisture, H2O, in your AC system, it can ice up the expansion valve, and stop the cooling effect. When the ice thaws, it will cool again for a while. Could this be it? Probably check your system for leaks, evacuate, and replace filter dryer. ..... Not at all sure that this it it ..... just for your consideration.

Dave's · 08-01-2007, 01:16 AM

Wasn't a Camry but I had the same problem once. Took forever to find it. The button activated a relay which was loose. The light was on but the AC would run sometimes and quit sometimes as the car jiggled the relay in and out of contact. Good luck.

Sniperdude · 08-01-2007, 01:25 AM

Most likely a bad compressor clutch. I have the same problem. Change your compressor entirely, or just the clutch. Up to you.

Blackhawk3D · 08-01-2007, 01:41 AM

I'd say first completely vacate the system, pull a good vacuum and refill with new r134 and see if that solves the problem.

davemac2 · 08-01-2007, 02:46 AM

besides the year, how about some more info? model? do you have auto temp control or sliders for the vent doors?

As already mentioned by Dave, it could be a faulty AC control header with a loose connection or many other things. The frozen TXV is something that can happen as well. Has there been any attempted repairs on the system by you or anyone else? Is their sealant in the system? The AC compressor will get hot during operation, but if it is overheating per chance, then it could be due to a slipping clutch, bad compressor. How long does it take after the system is on before it seems to stop blowing cold air? Is the amount of air being blown decrease at all, or does it just get warm?

Again, the more info the better,

dave mc

Landseer · 08-01-2007, 07:04 AM

Thanks for the replies, men. Please keep the ideas and experiences flowing and I'll keep reporting back.

As I mentioned, I've found many others plagued by what appears to be same symptoms. Gotta come to a scientific conclusion on this one. Time for me to learn A/C fixin, even if I need to buy special tools.

As for more information, so far ----
Camry LE, 4cyl, 220K mi. Has dial-type temp selector & dial-type fan switch. A/C activated by a push button. Green light shows steady on button when pressed. Not sure what other features to note. Does not seem to have auto temp control. It has a slider selector for recirc vs outside air.

Car bought new by DIL's family. She has driven for last 10 years and is a brainiac, drives like Maw Kettle., 5 miles under speed limit. Car used lightly for lots of miles. She can't recall any AC service ever. Car has had a few overheating episodes recently. New water pump, timing belt, head gasket. Also has new radiator and AC condensor coils (due to getting tagged in and intersection 2 years ago). Not sure what work was done on AC at that time, but it was minimal, surrounding replacement of the condensor. Since then, no AC problems until now. No other history of AC repair.

Symptoms are consistent with other accounts I've read. AC blows cold, works great for a while, then doesn't. Never know when it will or won't.

To recap ideas, Compressor clutch, compressor bearings, compressor circuitry on head of unit, expansion valve in heater box, switch in cockpit, low freon....

I did tighten the drive belt pretty tight, maybe I have put new, high stresses on the bearings and they are going south... more to follow, keep those cards and letters coming...

dc_98_cam · 08-01-2007, 07:53 AM

Try to find out if your filter/dryer was replaced when you had the new radiator and condenser installed 2 years ago. If somebody refilled the system without a new filter dryer, your AC system could be contaminated with something .... moisture or something else. .... Maybe you have an invoice or bill to refer to for the work that was done.

Stillrunning · 08-01-2007, 09:00 AM

Two more suggestions. There is an evaporator temperature sensor (thermister) that may be faulty. You'd have to remove it and test it in ice water for resistance values. Have you checked for a malfunctioning or leaking water valve (on firewall)?

keba · 08-01-2007, 10:46 AM

check connections to the a\c amplifier .next to the ECU .I had this issue and it drove me nuts until I found the fix ....

davemac2 · 08-01-2007, 01:21 PM

all the above suggestions are golden. Followup on those. For the A/C amplifier under the passenger dash area (I think), you can just try and pull the connector and re-seat it a few times to see if it makes a difference. I am going to bet that whoever put your new condensor in did not properly evacuate the system replace the receiver/dryer, and recharge. Unless that was done by a professional A/C shop and not some Joe Blow at the the body shop, then who knows what was put into the system? Who knows, the system may even have a leak and you are low on freon, or it was overcharged and now the system will cut out when the pressure becomes too high. The next stage of your diagnostics will be to see what is happening to the A/C system pressures when it cuts out. You want to observe the high and lo pressures with a decent set of gauges. If the compressor is cycling off with too high or too low pressures, then it would indicate some sort of blockage. If it is cycling off for any other reason, then there is probably a fault in the electrical system which you will need to start tracing.

dave mc

Landseer · 08-01-2007, 07:19 PM

Excellent ideas. Thanks for the help so far. I will definitely track through as many of these as possible. Might not get to it till Sat, though.

Today, similar symptoms. Ice cold air for 20 miles this morning. Parked car for 1 hr. Ice cold air for next 10 miles. Parked for 1 hour. Ice cold air for 15 miles Parked all afternoon. Ice cold air for 30 miles on way home, but got hot air for last few miles. Chills so well, when it chills, hard to believe it could be low on freon.

Morning outside air temps were 75 to 80. Late afternoon temps were 95 or so.

I'm beginning to think there is a hot compressor interupt switch... maybe the clutch or spindle bearings are going, combined with really hot outside temps, and being positioned right behind the radiator which is throwing max heat... I know how to check this --- remove belt and spin pulley; then, trip the clutch and spin the whole compressor shaft and feel for bearings.

More to follow.

Stopped on way home to price vac pumps, gages and other air conditioning tools. About $400 for what I need. Not ready to go there yet... but will before I pay 1G for service.

Stillrunning · 08-01-2007, 08:47 PM

I use an inexpensive combination Hi/Lo gauge I picked up at Advance. You have to disconnect/re-connect for Hi/Lo sides but with the Haynes A/C manual it works fine for me. Good A/C techs do practice a little art with the science they learned and the experience they have. Problem is trying to find the diamond you need. I found one that I use when I'm stumped, he's honest and skilled. Good luck.

Sniperdude · 08-02-2007, 09:18 AM

Let me know what you figure out, because I still haven't replaced my clutch, and if you find something else out, I'd actually like to try it myself.

I literally have the same problem as you.

davemac2 · 08-02-2007, 01:01 PM

Quote:

Originally Posted by Landseer

...Today, similar symptoms. Ice cold air for 20 miles this morning. Parked car for 1 hr. Ice cold air for next 10 miles. Parked for 1 hour. Ice cold air for 15 miles Parked all afternoon. Ice cold air for 30 miles on way home, but got hot air for last few miles. Chills so well, when it chills, hard to believe it could be low on freon.

Morning outside air temps were 75 to 80. Late afternoon temps were 95 or so.

The symptoms you have just described sound a lot like an overcharged condition. With a high ambient temp outside, if there is too MUCH freon in the system, the hi side pressure will get too high and trip the hi pressure switch to shut the compressor down. Inspect the condenser and its fan carefully to make sure there is nothing blocking the front and the fan and blades are in good shape too. THe next time it happens and you are home, pull out a hose and shoot some water in thru your grill onto the AC condenser and see if it brings your cold AC back again.

dave mc