96 Camry pulling 110 psi on low side AC - Toyota Nation Forum : Toyota Car and Truck Forums

timothyl2184 · 04-30-2009, 11:13 PM

I have a 96 Camry 4-cylinder with 210xxx miles on it. The AC has been acting sporadically for a couple of months now; it will blow cold air for a little while until the green AC indicator light starts flashing and then the air is no longer cold. When this happens you no longer hear the compressor engage. I was told to replace the magnetic clutch relay, which I did to no avail. Today I finally hooked up a pressure gauge to the low side port, and the readings were a little frightening. It's reading a 200 psi static (engine off) pressure that pulls down to a 120 psi when the engine is running and a 110 psi for the brief time that the compressor actually cycles on. It's getting hot and I'm going to need AC; am I looking at a new compressor, complete system overhaul, or what? Is the blinking light a failsafe? Any ballpark figures as to the cost I'm looking at? Thanks in advance.

Stillrunning · 05-01-2009, 06:37 AM

High low side could be a number of things. You'll need both the high and low sides to attempt troubleshooting. Your condition could be compressor if system is charged correctly. Static pressure depends on temperature. If engine heat is being applied to evaporator from heater it will raise static pressure. 200psi for 134a equals about 129F. Have you ever serviced the system yourself?

hill8570 · 05-01-2009, 10:42 AM

200psi static with a warmed-up engine isn't particularly out of line...I wouldn't worry about that.

As stillrunning mentioned, hard to make much of a diagnosis without manifold gauges on both the high and low ports at the same time. If you want to DIY, Harbor Freight has a half-decent set for around $40, although it's likely that for a complete fix-it-yourself you'll need a vacuum pump, too (again, Harbour Freight sells a half-decent electric one for about $90...don't waste your time with the cheap-o $15 compressor-powered pumps)

Before I'd suspect the compressor (unless it was noisy as crap), I'd suspect more mundane possibilities, such as air / water in the refrigerant or a duff expansion valve.

When's the last time the system was purged and the seperator / dryer replaced? Ever?

When the compressor is running, what does the sight glass in the seperator / dryer look like? Clear? Bubbly? White? Immediately after the compressor shuts off, what does the sight glass look like? White? Quick burst of bubbles? Nothing?

davemac2 · 05-01-2009, 02:09 PM

Make sure your rad fans are on and turning full speed when the A/C is on. The A/C amplifier will flash the button and disengage the compressor if it senses a too high or too low pressure in the system, or if some clutch slippage occurs. If you don't hear any compressor/clutch noises and your auxillary belt tension seems ok, then you arre probably experiencing too high of a pressure on the high side due to a blockage or a failed rad fan.

dave mc

***JohnGD*** · 05-01-2009, 08:57 PM

If your AC condenser fan working?

Quote:

Originally Posted by timothyl2184

I have a 96 Camry 4-cylinder with 210xxx miles on it. The AC has been acting sporadically for a couple of months now; it will blow cold air for a little while until the green AC indicator light starts flashing and then the air is no longer cold. When this happens you no longer hear the compressor engage. I was told to replace the magnetic clutch relay, which I did to no avail. Today I finally hooked up a pressure gauge to the low side port, and the readings were a little frightening. It's reading a 200 psi static (engine off) pressure that pulls down to a 120 psi when the engine is running and a 110 psi for the brief time that the compressor actually cycles on. It's getting hot and I'm going to need AC; am I looking at a new compressor, complete system overhaul, or what? Is the blinking light a failsafe? Any ballpark figures as to the cost I'm looking at? Thanks in advance.

***JohnGD*** · 05-01-2009, 09:00 PM

Yeah, Toyota issued a massive expansion valve recall in the mid 90's. It's possible that they still are defective but they now use the 3-year bumper-to-bumper policy to cover it.

The blinking AC light simply means the RPMs between the compressor and engine are different. It could be because the compressor stopped (for whatever reason), the belt is too loose, etc etc.

timothyl2184 · 05-01-2009, 11:26 PM

Thanks for all the responses. My AC experience is extremely limited at best, but based off of everyone's suggestions here's what else I have. The belt tension seems ok, and there are no cracks or visible damage to the belt. I got the car last August and it came with full maintenance records, and the only previous AC work I found was a system flush and recharge about 4 years ago. Both radiator fans are engaged and moving at full speed when the compressor is engaged, and in the sight glass you can see a white foam when it's operating and then a quick burst of bubbles immediately after it shuts off. For the limited time that the compressor actually works (varies from 10 seconds to 5 minutes) ice cold air pours from the vents, but then the flashing light starts. I'm hoping to find the cheapest solution possible, and I'm afraid to take it in for service without some more knowledge on the subject so I don't get had.

hill8570 · 05-01-2009, 11:53 PM

Quote:

Originally Posted by timothyl2184

Thanks for all the responses. My AC experience is extremely limited at best, but based off of everyone's suggestions here's what else I have. The belt tension seems ok, and there are no cracks or visible damage to the belt. I got the car last August and it came with full maintenance records, and the only previous AC work I found was a system flush and recharge about 4 years ago. Both radiator fans are engaged and moving at full speed when the compressor is engaged, and in the sight glass you can see a white foam when it's operating and then a quick burst of bubbles immediately after it shuts off. For the limited time that the compressor actually works (varies from 10 seconds to 5 minutes) ice cold air pours from the vents, but then the flashing light starts. I'm hoping to find the cheapest solution possible, and I'm afraid to take it in for service without some more knowledge on the subject so I don't get had.

Fan operation sounds good. Flush and recharge 4 years ago is plenty recent. Hope they replaced the seperator / dryer when they did it, 'tho. Just gotta assume the dessicant in a dryer that old is pretty much saturated.

The white foam in the sight glass means she's a mite low (a can or less) on refrigerant, but that shouldn't be enough to cause the problem you're seeing. Shouldn't hurt anything to grab a refill kit of R134 and slowly top it off until the milky white turns clear. I'd be insanely surprised if that fixed your problem, 'tho.

Any chance you could put your gauge on the high pressure port and see what it's doing while the compressor is running? Better to see both high and low at the same time, but you gotta do what you gotta do.

***96paseo*** · 05-01-2009, 11:54 PM

It sounds like you have some NCG in the AC system. NCG = non compressible gases. Its best that you have the system evacuated with a pump before putting a refrigerant charge into it. The low side should only have between 30-40 psi charge during normal operation.

timothyl2184 · 05-02-2009, 12:11 AM

Thanks hill8570. Unfortunately the gauge I have is a crappy little piece I borrowed from a buddy that only has a low-side coupling. I will try to scrounge up a better gauge tomorrow and see what I can find, but in the meantime do you have any ideas as to what we're looking at?

On a side note, should the low side have enough pressure in the line to launch the coupling 4-5inches up when it is released from the port? I've never seen that kind of pressure in an automotive system, but then again my experience here is limited.

***JohnGD*** · 05-02-2009, 12:25 AM

Read this link and look at Figure 14:

http://www.procarcare.com/icarumba/r...opedia_ac3.asp

"Oils streaks (A), constant bubbles (B) or foam (C) indicate there is not enough refrigerant in the system. Occasional bubbles during the initial operation are normal. "

If it's cold when working, then my guess is that is probably just low on refrigerant? A can from Walmart is about $10. But like other said the pressure should be much lower than 110 psi. So check with a pro to see if there are other problems than low refrigerant (you don't want to burst the system).

Quote:

Originally Posted by timothyl2184

Thanks hill8570. Unfortunately the gauge I have is a crappy little piece I borrowed from a buddy that only has a low-side coupling. I will try to scrounge up a better gauge tomorrow and see what I can find, but in the meantime do you have any ideas as to what we're looking at?

On a side note, should the low side have enough pressure in the line to launch the coupling 4-5inches up when it is released from the port? I've never seen that kind of pressure in an automotive system, but then again my experience here is limited.

***JohnGD*** · 05-02-2009, 12:28 AM

You removed it when you have 110 psi that is what happens. Just like removing an air tool even with 90 psi.

Did you ever get down to 30-45 when working? I think that's what the Interdynamics gauge suggests.

See How-to guide:
http://www.id-usa.com/how_to.asp

Quote:

Originally Posted by timothyl2184

On a side note, should the low side have enough pressure in the line to launch the coupling 4-5inches up when it is released from the port? I've never seen that kind of pressure in an automotive system, but then again my experience here is limited.

Stillrunning · 05-02-2009, 04:24 AM

Is the low side piping hot to the touch? Trying to charge system without a high side gauge is NOT recommended! Properly operating system will show about 21-35 low side psi and 200-227 high side psi. It is possible you have air/water in system. Safest course of action would be to evacuate, pull vacuum for about 20-30 minutes with engine and evaporator hot and re-charge - spray condensor with water at about 2/3 full. Empty system will hold about 30oz +- 1.75oz. Inexperience with A/C systems will end up costing you more money - take it to professional. I have to question why system was "flushed" and re-charged 4 years ago?? This sight can be helpful: http://www.aircondition.com/ as they have a forum with experienced people, but you will need to post high and low pressures, ambient, outlet air temp, etc.

Edit: Some other considerations from above web site forum: http://acsource.net/acforum/viewtopic.php?f=1&t=7560

A/C is part art, part science and nothing works better than experience.

hill8570 · 05-02-2009, 11:48 AM

Quote:

Originally Posted by timothyl2184

...but in the meantime do you have any ideas as to what we're looking at?

My best guess right now is system contamination (air, water or both) or a duff expansion valve, although we haven't ruled out a leaky compressor. The "runs anywhere from 10 seconds to 5 minutes" thing is a bit strange, 'tho.

When the compressor is running, is the piping leading to to the low-pressure port (before it goes to the condensor) pretty hot to the touch, pretty cold (frosty or almost so), or just kinda in the middle?

timothyl2184 · 05-02-2009, 01:03 PM

OK, I just hooked up a gauge to the high side and it pulls 210 psi during operation. As for the question about the piping leading to the low side port, it's blistering hot during operation. I was reading elsewhere online that a possible cause could be a faulty "compressor lockout sensor" and that is what causes the light to flash. Does this sound like a reasonable explanation as to at least why it doesn't work? I don't know if this is something I can fix myself, but I don't want to haul it to the garage and get ripped off on stuff I don't actually need.