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2005 Corolla AC Problems Pages: 12

Koppster on Tue November 03, 2015 6:19 AM User is offlineView users profile

Year: 2005
Make: Toyota
Model: Corolla
Engine Size: 1.8
Refrigerant Type: R-134A

I have been trying to determine what is wrong with our daughter-in-law's 2005 Corolla. The primary problem is it does not blow cold air (50 degrees at vent).

Initially, I took readings 28-30 lo/250 high @1500 rpm...ambient 90, vent reading 60. The clutch was cycling in and out about 6 seconds on/20 seconds off (fan comes on with compressor). That ratio has varied a bit along the way but safe to say, the clutch cycles in/out.

I have replaced the cabin air filter, inspected the condensor, injected UV dye in to the system and inspected for leaks 4 or 5 times. I don't see any obvious leaks.

Saturday, I vacuumed the system down to 28/29 mmHG for 30 minutes, disconnected and watched for leaks....it crept left to 25/26 after about an hour or hour and a half....attributed that to schrader valve system.

Recharged the system with 1.5 12 oz cans (system requirement is 17 oz) and now the system reads with compressor off 32/125; when compressor kicks in 12/160.

Added the other half of the can and no change.

I'm at a loss here, what might be wrong?

Here is the thread telling the whole story:

http://www.toyotanation.com/forum/132-9th-gen-corolla-1st-gen-matrix-2003-2008/1206426-05-corolla-ac-problem-need-advice-expertise.html

Thanks,
Rick

Dougflas on Tue November 03, 2015 4:17 PM User is offline

I read some of the posts on the other forum. When you added R134 with the dye, did you add it with the can inverted? If you didn't , you won't get much dyd into the system thus you won't see a leak with the light.

Koppster on Tue November 03, 2015 5:18 PM User is offlineView users profile

Yes I did invert the can but to your point, I am considering the purchase of a sniffer

That said, what mystifies me is how you can vacuum a system down, have it hold the vacuum, then charge with the proper amount of freon and have it read way low? What does that indicate?

Edited: Tue November 03, 2015 at 5:31 PM by Koppster

mk378 on Tue November 03, 2015 7:06 PM User is offline

If you have a TXV system with a fixed displacement compressor and basic economy car control panel, it is designed to cycle on evaporator temperature.

This means that once you have the compressor cycling, the evaporator isn't going to get any colder no matter what you do under the hood.

Two things could be happening to keep the vent air from going down to 40 like it should-- either reheating from the heater core, or cycling off too early due to the evaporator sensor being out of calibration.

Koppster on Tue November 03, 2015 7:19 PM User is offlineView users profile

I pulled the glove box and cycled from hot to cold, I could hear the blend air door opening and closing. I assume that means it's functioning

How would I know if I have a TXV system and what does that mean?

Where would the evaporated sensor be? Any way to test or adjust...replace?

How do your thoughts factor in to the low readins after vacuum and charge?

Edited: Tue November 03, 2015 at 7:21 PM by Koppster

mk378 on Wed November 04, 2015 10:18 AM User is offline

Is there a water valve on the firewall in one of the heater hoses? If it has one it needs to close fully when the dash knob is set to full cold.

Was your ambient lower during the second test? Those refrigerant pressures would be typical at 70 or so.

Koppster on Wed November 04, 2015 11:16 AM User is offlineView users profile

The ambient was low to mid 70s

Not sure if there is a water valve but I was advised to disconnect the heater hoses and connect them together as a means to determine if it is blend air door issue

I read something om a site (agcoauto.com) that said "lower than normal pressure on both gauges....can also be caused by a malcunctioning variable displacement compressor". Makes me wonder because the compressor cycles so quickly and some who have heard it believe it is a little noisy

Edited: Wed November 04, 2015 at 11:47 AM by Koppster

mk378 on Wed November 04, 2015 3:44 PM User is offline

Pressure of 12/160 is perfectly normal at low ambient. You need a higher ambient to conduct meaningful A/C tests. The compressor for that car is not variable displacement.

Koppster on Wed November 04, 2015 4:24 PM User is offlineView users profile

Thanks and if I'm reading you correctly, all you can recommend is to rule out radiant heat from the heater core via malfunctioning blend air door?

Also, is there any chance this could be caused by the ambient air temperature sensor?

Thanks!

Edited: Wed November 04, 2015 at 4:56 PM by Koppster

mk378 on Wed November 04, 2015 9:43 PM User is offline

I don't know that particular model, but if it is simple "bang-bang" economy car controls, the only sensor controlling the cycling off of the compressor would be a thermistor mounted in or near the evaporator.

How cold does the low side pipe from the evaporator to compressor get?

Edited: Wed November 04, 2015 at 9:44 PM by mk378

Koppster on Thu November 05, 2015 4:12 AM User is offlineView users profile

I have not measured the actual temp on the low side pipe, but it is cold (no frost) and sweats.

And yes, according to the parts diagrams for the car, the thermistor is mounted on the evaporator. This car is not easy access to the evaporator or the expansion valve, requires dash removal.

So, what is your recommendation going forward?

Edited: Thu November 05, 2015 at 8:13 AM by Koppster

bohica2xo on Thu November 05, 2015 11:57 AM User is offline

Your pressures are low. You had a vacuum leak of some sort, but see no leaks. This makes your couplers a place to look.

If you work on the car very much,you should get a Mitchell or Alldata subscription. This gives you the full FSM, which shows the location of all of the sensors, test procedures etc.

I show a pressure switch for that vehicle in the refrigeration loop. Without an FSM I can't say if this is a high side or low side switch, but it may be a reason for cycling.

.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

Koppster on Thu November 05, 2015 12:07 PM User is offlineView users profile

I am considering the purchase of a Robinair TIFXP-1A Automatic Halogen Leak Detector....good idea?

I have had no luck spotting leaks with the UV dye. However, the system did hold the vacuum fairly well when I pumped it down so makes me wonder if there is a leak?

I'll try to find the pressure switch you are referring to; I have access to a parts diagram.

Thanks for chiming in, appreciated.

Edited: Thu November 05, 2015 at 12:13 PM by Koppster

Cussboy on Thu November 05, 2015 1:18 PM User is offline

Many use a combination of methods to find leaks: UV dye, sniffer, looking for oily residue, soap bubbles even.

Sniffer seems to be best for evaporator leaks, but sometimes dye can be observed in the condensate drain tube. Compressor seal should always be considered a suspect. same with any fittings/connections.

I found/confirmed a hole in my own evaporator in 2002 using soap bubbles, after seeing a buildup of oil residue there.

Dougflas on Thu November 05, 2015 2:24 PM User is offline

Quote
Originally posted by: Koppster




I have had no luck spotting leaks with the UV dye. However, the system did hold the vacuum fairly well when I pumped it down so makes me wonder if there is a leak?



.



Thanks for chiming in, appreciated.

You could have a leak that only shows up under pressure. Compressor shaft seals are known for this.

Koppster on Fri November 06, 2015 8:52 AM User is offlineView users profile

Koppster on Fri November 06, 2015 8:55 AM User is offlineView users profile

FWIW, at one point I hooked up guages to a known good Corolla (08 but identical series/system) and got the following, please note the comparisons were made BEFORE the problem car was discharged, vacuumed and recharged:

Static: 75/175 vs problem car 56/165

Initial idle compressor cycled but after it warmed up (5 minutes) it quit cycling and the clutch stayed engaged...ambient 80+...problem car cycles quickly even when warm

1500 RPM after 5 minute warmup: 30/220 vs problem car 28-30/250

NOTES: Compressor stays on after 4 minute warm up and at 1500 RPM...need to check this on problem car

What's interesting to me is the compressor quit cycling on the good car and further, the pressure readings were pretty darn close BEFORE discharging, vacuuming and recharging. Does this mean anything to anyone? Compressor problem?

And to remind, after discharge, vacuum and recharge I now get readings of 12/160 and the compressor still cycles

Edited: Fri November 06, 2015 at 9:04 AM by Koppster

bohica2xo on Fri November 06, 2015 11:14 AM User is offline

The clutch cycles because of an electrical signal. Your low pressures indicate either a low charge or low ambient temperatures.

As I said before, there is a pressure switch in that car. If you are undercharged, it may be shutting the system off. Or the switch could simply be bad.

The long "off" time vs the short on time for the cycling is often a low charge.

You need the FSM.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

Koppster on Sat November 07, 2015 9:59 AM User is offlineView users profile

Thanks, I might be ready to throw in the towel and take it in to an AC shop for evaluation. I spoke with a local guy yesterday and he was very helpful. He believes there is a small leak somewhere, probably the evaporator and the contamination from the leak has worn the compressor down over time. He said he would diagnose for free (because I'm military). Very nice offer but I'd feel terrible taking advantage of him, would have to compensate but at least I would have a better idea of what to tackle.

Also, I ordered the Robinair sniffer, suspect it will come in handy and I plan to use it to see if picks up something I didn't detect with the UV, in particular under the dash near the evaporator.

Finally, I respect the opinions of folks more experienced than me but it sill mystifies me as to why the charge went from close to normal to 12/160 AFTER vacuum and recharge.

Thanks again, appreciate the patience and help.

Edited: Sat November 07, 2015 at 10:10 AM by Koppster

bohica2xo on Sat November 07, 2015 12:11 PM User is offline

So, you had a cycling problem before you discharged the system. It may have been low on charge at that point, or an issue with a defective sensor was causing the cycling.

Once you discharged the system, you attempted to evacuate it with leaky equipment. Probably never got close to a proper sub-1000 micron vacuum.

You then recharged it with the same leaky equipment, to some level.

Your pressures after recharge are too low, and indicate a low charge - or faulty measuring equipment. If it was leaking the pressures would continue to decline.

You seem to be convinced there is a leak, even though the low pressures happened after you worked on it. Rather than spend the $26.95 for an Alldata subscription that would give you the FSM, including component locations and troubleshooting data for the system controls & sensors... you are buying a sniffer.

Good luck with your project.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

Koppster on Sat November 07, 2015 12:23 PM User is offlineView users profile

I genuinely appreciate your help and I am NOT convinced there is a leak. I am simply sharing what I have done and what I have observed, smart or dumb, and seeking advice from experts. I hear you on the All Data and will look in to it but I really don't understand the criticism for purchasing a tool to help with troubleshooting. I also don't understand why you believe the equipment I am using is leaky. I vacuumed the system down to 29 and some change, it did creep to 26 after an hour an a half or so...I was advised on another forum that was probably just from the connections. Anyway, once again, just here seeking advice and I do appreciate it.

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