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Old 10th March 2011, 00:53   #1
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Default Corolla A/C Problem - Diagnosis,Solutions,Experiences

Had a minor issue with the ac in mid-Dec .This is a 2003 Corolla with 68k on odo.

By putting the ac on AUTO with the temp setting even at coldest,the cabin wasn't cooling enough.I suspected that refrigerant must have leaked out,so got the pressure checked.

Got approx 200g of refrigerant topped up to take the suc pressure to approx 35 and discharge pressure to 130psi levels.

The problem surfaced again last week.

I checked with AC Technicians and was told that one needs to open up the dashboard to pull the AC unit out(the heater core would also need to be disconnected).

Seeing this as a hassle ,I went in for my trial#2 with my old trusted Technician,Ravi.

With the ac pressure gauges connected to the lo and hi side ports , the gauges showed a low side(compr. suction) pressure of 20psi and hi(compr. discharge) of 140 psi ; after stopping the unit , got the system depressurised and found that there was only air in the system.

I used a bit of my experience of commissioning and operating large Propylene Refrigeration systems and applied the same principles in the car ac.
  1. Had all air removed , checked the complete system for signs of oil(refrigerant oil shows up in case there's a leak).
  2. Had vacuum pulled till almost full(-76cmHg) and put system on hold for approx 20 minutes;vacuum was holding
  3. Added approx 80 ml of fresh refrigerant oil.
  4. Got a fresh refrigerant charge approx 600g ; this was from two sealed cans (each having 500g)
  5. system worked perfect ;Grille temperature recorded was 8.5deg.C
I'll now need to observe the performance of the unit.If refrigerant charge goes low again, I'll suspect the compressor seal ; and if that happens,I'll be sorry to state that Toyota quality is all rubbish.

My experiences with my earlier pre-owned cars' ACs:
  1. Premier Padmini 1993 model-92000km on odo - acquired in 1998 & sold in 2000 - Superking AC - had the compressor seal replaced and two leaks on the evaporator coil fixed within two months of purchase - cost me Rs.1800 then
  2. Maruti Esteem 1995 model - 66500km on odo - acquired in 2000 & sold in 2004-Subros AC - got the unit serviced and fresh refrigerant charged in 2002 - no leaks found - service cost Rs.1200
  3. Maruti Versa 2003 model- 21900 km on odo - acquired in 2004 & sold in 2010- no job done on ac except keeping the cabin clean and a routine low pressure wash on consenser fins.
I know of people in the US who have been using cars for 15 years with trouble free ACs, so can't understand why we face such issues on cars even younger.

Mods:You can merge this thread with other Corolla AC threads if you wish.

Last edited by vigsom : 10th March 2011 at 00:55. Reason: additions
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Old 10th March 2011, 10:15   #2
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Default Re: Corolla A/C Problem - Diagnosis,Solutions,Experiences

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I know of people in the US who have been using cars for 15 years with trouble free ACs, so can't understand why we face such issues on cars even younger.
Low temps in US and high in India will make a difference in the life of AC. Compressors in India need to work very hard I guess. Also ours is mostly stop and go traffic condition (relative to US) so the compressor speed will keep varying with RPM. Lastly, could be also due to the quality of parts used in HVAC system but I am not sure of this.
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Old 12th July 2011, 20:12   #3
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Default Re: Corolla A/C Problem - Diagnosis,Solutions,Experiences

I was on leave for a week and when I returned ,I checked that the Corolla ac compressor would not cut in ; rather surprising because the ac worked super perfect for four months and even on the day I left on leave.

checked the pressure in the system and there was none - just a low "pssssssssss" when the low pressure side valve was pressed.

Took the car to my technician.

We pressurised the system to 350psig and did a leak check of all hoses,all joints - no abnormalities seen.The pressure held for 10 mins or so but then all of a sudden dropped by 10 psi and again held - strange phenomenon

The ac technician looked under the compressor using a powerful light and felt traces of some darkish deposits below the compressor body.

He removed the compressor and opened the clutch - a small weephole on the Compressor casing showed oil - indicating that there was an oil seal leak.

Surprisingly,the seal leak did not show up even when the compressor alone was pressurized to 350psi and dipped in a bucket of water.

He said that seals show up only in operation and may not show symptoms of leak in standstill mode.

By then I had to leave for work and so could not see the rest of the action.

He replaced the seal - but also found one gasket shaped like the "intel inside" icon, damaged in small pieces.

This gasket is approx 1mm thick and runs around the casing vane ;there are two such gaskets - one on each part of the compressor when the Compressor is split in two.

The gasket was not available anywhere but he managed to use one from an old damaged compressor lying at another mechanic's place.

The compressor is now fine(fingers crossed)

Total cost

Gas recharge+oil+leak test labour - 1200
Gasket - 100
Compressor overhaul labour 350
oil seal 350

that makes it 2000 bucks - not bad for a Corolla :-)

Let's see how the fella works now.
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Old 24th July 2011, 01:26   #4
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Default Re: Corolla A/C Problem - Diagnosis,Solutions,Experiences

Vigsom wrote"Got a fresh refrigerant charge approx 600g ; this was from two sealed cans (each having 500g)"
Vigsomji,did your car require 600gms or 1000gms(2 sealed cans of 500gms each) of the refrigerant?
Your AC technician is quite right, a static leakage test is no guarantee that there will be no leakage in actual usage conditions.
A cars' AC system has to function in a much more hostile environment than a static room AC-high ambient heat conditions under the hood,dust,vibration, jerks, varying compressor speeds, heat pouring in thru the metal body/all round glass etc.
Ravi appears to be a canny, experienced guy, probably you wont have any further problems, touch wood. (all the same!).
A tip that I've found very helpful is to periodically pressure wash the condensor & radiator; Delhi being an extremely dusty place, I get this done twice a month in the hot season & it keeps up the efficiency of these two heat exchange components.
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Old 11th December 2011, 19:45   #5
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Default Re: Corolla A/C Problem - Diagnosis,Solutions,Experiences

Looks like by the time I say bye to this car, I'd have become an AC expert.

Noticed a strange noise from under the hood after a drive ; checked that even with the ac switched off, the ac compressor is rotating at a low rpm(say, 1 revolution in 4 secs or 15rpm)

Switch on the ac , the clutch engages and the Compressor operates nomally.Switch it off and the clutch does not totally disengage.

I can think of two causes

there seems to be something that is stuck between the compressor pulley and the clutch and that is causing slow rotation of the compressor

OR

the wiring harness to the Compressor is not getting totally de-energised viz.even after switch off , the line continues to carry a minor voltage which is causing partial engagement of the clutch


watch this space for more details.
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Old 12th December 2011, 16:52   #6
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Default Re: Corolla A/C Problem - Diagnosis,Solutions,Experiences

Quote:
Originally Posted by vigsom View Post
Noticed a strange noise from under the hood after a drive ; checked that even with the ac switched off, the ac compressor is rotating at a low rpm(say, 1 revolution in 4 secs or 15rpm)

Switch on the ac , the clutch engages and the Compressor operates nomally.Switch it off and the clutch does not totally disengage.

watch this space for more details.
The fault was rectified in 10 minutes ; the compressor clutch disc was opened(in position),a washer inserted and disc fitted back.

Bingo !!!!Aaal izzz well.
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Old 15th December 2011, 00:41   #7
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Default Re: Corolla A/C Problem - Diagnosis,Solutions,Experiences

Quote:
Originally Posted by vigsom View Post

Noticed a strange noise from under the hood after a drive ; checked that even with the ac switched off, the ac compressor is rotating at a low rpm(say, 1 revolution in 4 secs or 15rpm)

Switch on the ac , the clutch engages and the Compressor operates nomally.Switch it off and the clutch does not totally disengage.
Quote:
Originally Posted by vigsom View Post
The fault was rectified in 10 minutes ; the compressor clutch disc was opened(in position),a washer inserted and disc fitted back.
The problem resurfaced,but this time after the ac was on and the car had run 15kms.

Strangely,leave the car standstill for 7-8 hrs and start ; no noise.

Run the car for ,say 15kms,with the ac on,and the noise starts everytime the compressor cuts off.

When the compressor cuts in all is well ; when it cuts off , the noise begins - the noise is akin to what you hear when you place a metallic strip against a moving disc and it is very very embarassing.

Step 2 would be to open up the Compressor pulley (only the clutch + pulley) and see what's wrong.

The car has never done more than 2000rpm in the last year and so I can't understand how this noise cropped up all of a sudden one day.
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Old 15th December 2011, 11:42   #8
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Default Re: Corolla A/C Problem - Diagnosis,Solutions,Experiences

Quote:
Originally Posted by vigsom View Post
Strangely,leave the car standstill for 7-8 hrs and start ; no noise.

Run the car for ,say 15kms,with the ac on,and the noise starts everytime the compressor cuts off.
Sounds like a bad bearing in the clutch. When the AC is on then this bearing is not in play (the clutch is locked to the compressor). When it is off then the clutch is essentially 'freewheeling'- ergo the bearing comes into play.
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Old 15th December 2011, 12:11   #9
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Default Re: Corolla A/C Problem - Diagnosis,Solutions,Experiences

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Originally Posted by vigsom View Post
- the noise is akin to what you hear when you place a metallic strip against a moving disc and it is very very embarassing.
Are you saying that you cab actually hear this sound inside the cabin ?

Quote:
Originally Posted by sgiitk View Post
Sounds like a bad bearing in the clutch. When the AC is on then this bearing is not in play (the clutch is locked to the compressor). When it is off then the clutch is essentially 'freewheeling'- ergo the bearing comes into play.
Seems like the perfect technical explanation.
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Old 26th December 2011, 21:31   #10
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Default Re: Corolla A/C Problem - Diagnosis,Solutions,Experiences

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Switch on the ac , the clutch engages and the Compressor operates normally.Switch it off and the clutch does not totally disengage.
watch this space for more details.
The problem was because the bearing,which is tightly pressed into the pulley,had come out causing the pulley to sway and thus rub against the clutch disc.

The clutch assembly was not available as a spare ; we've tried a local engg. solution by inserting a shim between the pulley body and the bearing, and additionally punching around the pulley bearing housing so that it holds the bearing in place

Cost - just the refrigerant

let's see how this works

The pic would make things clear
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