Car AC Diagnosis of Various Symptoms Dedicated Thread

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afnan.bashir (afnan.bashir) 2014-06-10 07:03:13 +0500 #41

@xulfiqar please give me some direction to proceed

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afnan.bashir (afnan.bashir) 2014-06-10 14:16:55 +0500 #42

Update: I pressurised the system to 300 PSI today. When the car was hot the schrader valve had very minor leak i poured soapy water. As soon as car went cold the leak stopped.

My mechanic said as a last resort he would remove everything and pressurise everything condenser and evap and then dip in large water reservoir to see if it leaks. Same technique as checking puncture.
@xulfiqar what did you do to check leaks? are UV dyes available here? any alternative?

afnan.bashir (afnan.bashir) 2014-06-11 15:55:51 +0500 #43

In order to check if my Schrader valves are leak when they are hot I added balloons red high side and blue low side. If only they hold enough temperature I plan to make car stand under direct sunlight.

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Xulfiqar (Xulfiqar) 2014-06-11 16:43:37 +0500 #44

if you still have the old type R12 schrader ports then try tightening them with a tyre valve stem tool. There are UV dyes available in Karachi at large HVAC shops and even sniffer units - expensive to buy.

afnan.bashir (afnan.bashir) 2014-06-11 16:56:37 +0500 #45

Yes I have the same. Good idea ill tighten them. Any idea what does that dye cost ?

Xulfiqar (Xulfiqar) 2014-06-11 17:39:53 +0500 #46

abuot Rs 1000/- for 200 ml about 8~10 yrs ago, you only need to add about 30 ml to a running system.

syncview (Osama Abbas) 2014-06-11 18:40:13 +0500 #47

if you can't find the dye inject about 50 to 60 grams of R22 then pressurize the system. that refrigerant knows its way out if there is a leak

Xulfiqar (Xulfiqar) 2014-06-11 19:32:21 +0500 #48

you need a sniffer to detect it correctly.

SER_GTR (SER_GTR) 2015-04-29 15:21:11 +0500 #49

What Are Updates On This One....This Season I Am Planning To Do Same With My AE101..FF A/C

It Have Serpentine Type Condensor With Rotary Denso Type Compressor And It Use R134a I Guess

Condenser Is Done With Its Life ..Bend Fins So Thinking Of Replacing...So I Was Inclining To Get Parallel Flow Condenser But I Doubt I Would Find Any That Fit The OEM Fitting And I Am Not Happy To Get Lines Plumb....

Have Very Bad Exp With Custom Plumb Lines On My Nissan...They Leak Every Single Time.....

Will Pull Vacuum On System And 1st Check For Leaks And Then See If Condenser Can Work Or I Need A New One.....

Will Prepare Eveything 1st Then Go For It....

SER_GTR (SER_GTR) 2015-04-29 15:23:48 +0500 #50

@xulfiqar Acetone.....Will Find It On Liberty Tariq road Market????

I Am Also Interested In Getting UV Dye ...Very Easy To Find Leaks But I Wish I Get Some Decent Answers When I Ask...Not Some ALIEN Looks As People Usually Don't Do These Kinda Things In Their Common Practice

afnan.bashir (afnan.bashir) 2015-04-30 03:17:30 +0500 #51

Well could not find a dye here in lahore. They use traditional bubble test method. My previous car had some leak but it leaked when AC Runs. We fiddled too much. Then mechanic came up with a thing that he pulled cooling coil, Compressor and Condenser. Made fittings for them. Pressurized them and tested them after pumping air. Just like puncture. Nothing leaked. But when pressurized compressor was submersed in water and its pulley was rotated vola big bubbles.

Secondly when sometimes compressor wont engage and it always too much load on car when AC Runs. It came to be bad TXV. That single season i got AC work done 4 times in a month.

afnan.bashir (afnan.bashir) 2015-04-30 03:22:26 +0500 #52

Now I have CL7. Problem i am working on is AC will cool intermittently. Will put load on engine too much. High Pressure side after condenser is warm and so is the low pressure line with moderate cooling in cabin. Line from Compressor to Condenser is super duper hot. Mechanic tried to put gauges but could not put gauge on High side because if its location his adapter was not getting through.

I suspect bad Condenser and will work on that this weekend. Even i know my PhD exam is near too
@xulfiqar i am confused about one thing. When i change condenser and clean other system

How to make sure compressor has required ammount of oil i.e it is not over charged Manual says it needs 160 ml
How to test the health of compressor?
I have heard that TXV dong go bad on these cars should i change it?

afnan.bashir (afnan.bashir) 2015-04-30 03:29:29 +0500 #53

@xulfiqar
1. WHy do you need to pull vac for one hour?
2. What should be ideal low side reading and high side reading? lets take ambient temp to 30
3. Why oil is at different places, cant understand why do we need oil other than compressor.

Procedure is ?
1. Fill reqired oil in all places
2. Pull vac
3. On weighing machine put cylinder and attach to low side.
4. Release the gas so that it has some to start the comp
5. Start the car, raise the RPM to 1.5 k
6. Fill the gas to range of weight
7 it should be ice cool then

SER_GTR (SER_GTR) 2015-04-30 04:33:09 +0500 #54

We Are Those CHAP Who Spend More Time Working On AC System In HOT Summers Then Enjoy It......... I Never Enjoyed A/C W.o Any Trouble In My Entire Life For LoNG Expect HOME

Here Its Like...You Have A Zero Meter Car Or A JAPANI ReKONDITION Then U Can ENJOY Until U Mess It UP Then Mostly It Slows Down...Leak Leak Till Owner Either Sells It For Issue Or Bear With No A.C As Patience Of People Like Me End When We See Face Of So Called A/C Technician More Than Our Friends

SER_GTR (SER_GTR) 2015-04-30 04:50:42 +0500 #55

afnan.bashir;4775741:

Now I have CL7. Problem i am working on is AC will cool intermittently. Will put load on engine too much. High Pressure side after condenser is warm and so is the low pressure line with moderate cooling in cabin. Line from Compressor to Condenser is super duper hot. Mechanic tried to put gauges but could not put gauge on High side because if its location his adapter was not getting through.

I suspect bad Condenser and will work on that this weekend. Even i know my PhD exam is near too
@Xulfiqar i am confused about one thing. When i change condenser and clean other system

1. How to make sure compressor has required ammount of oil i.e it is not over charged Manual says it needs 160 ml
2. How to test the health of compressor?
3. I have heard that TXV dong go bad on these cars should i change it?

Test The Faulty Condensor By Putting Water on It While Its Getting HOT Or Putting Load...Head Pressure Should Drop Down And Cooling Will Get Better For Time Being....Then Its Condensor....

I Recommend To Open It Complete As You Are Unknown What Previous Owner Do....B.t.w Congrats For CL7 And Tarraqi Its Surely A Safaid Haathi If U Get It In Messed Up Condition
Anyways completely Open.......Drain Compressor Oil Completely Measure It ...Put Fresh New OIL 160ML Distributed On other Sides Of Parts Too...

Flush Lines....Clean EVAP COIL ANd Replace TXV If You Even DOUBT With OEM Type

Replace Condensor If Its Busted Up From Front....Replace All O-rings........I Suggest To Replace Shreader Valves Also For Peace Of MIND....New Filter To Be Placed And Installed Within 5-10min ..Just Do All Work ..Just Open And Install It...

Pull A Good Deep Vaccum For Atleast 1 HOUR....Reason We Do It For 1 Hour Is To Actually Remove All Atmosphere As Much As We Can frm System + Leftover Vapours Need To Be Heated And Evaporated Out So It Takes Time....Thats Why Its Recommend Atleast For 30+ Min To Pull Vacuum..... Best Is To Purge Parts When Cleaned With Nitrogen But Not All Can DO So Deep Vacuum Will Do The JOB

Beforre Doing That I Recommend On This Charge Is To Pressure Check High Low Side Pressure....Usually A Busted Compressor Have Same HI/LO Sides Equal Or Weak Compressor Will Have Low HI Side.....But It Can Be Due To Other Symptoms Also....So Actually You Can't Judge It All Time By Pressure Test But Can Get Idea ....... You Can Also Put More R134a In System If Its Low And Check or Leaks On Compressor

After Doing All This......I Guess One Should Be Clear Of Many Doubts As Everything Is Done.....

Also What I See Is R134a O-rings Are Green In Color And Diff Then r12 Types.....So Also Make Sure While Buying O-rings And Ask For R134a type.....!

SER_GTR (SER_GTR) 2015-04-30 04:55:27 +0500 #56

I Am Also Going To Take Panga With My System Soon......Will Be Inspecting Parts And Everything Before Getting Into It....

Have To But Some Tools And Stuff Before Starting....It Will Be Khuari I Know But FUN !

afnan.bashir (afnan.bashir) 2015-04-30 05:28:33 +0500 #57

Thanks for the wish car is pretty much OEM. Brought it from your city. Came to karachi especially to get a CL7. First deal was in 9 lac. But when reached khi it was accdiented. so i refrained away from it. Searched and got this one.

Well i think pressures on H and L may be the same as they are on same temp. But i was confused why it is extremely hot before condenser. Also if compressor puts load on engine it is trying to push gas and i think condenser is blocked

SER_GTR (SER_GTR) 2015-05-01 05:35:45 +0500 #58

Extremely Hot Before Condensor Means Compressor Is Pushing It COmpressed And It Should Be HOT....After Condenser It Should NOT Heat Same.....If It Does Then Your Condenser Is Not Heat Exchanging Properly...

Diagnose System And Note FLAWS....Then Once You Open Everything Apart...Check Them Thoroughly.... As Told You...Do Everything And In End.....Compressor Is The Last Resort To Change.....!!

How Many Km's Its Done???? They Do Good For Like 150k km But You Never Know How Much Its Used On Stationary Condition In JAPAN :3

capsat (ومن شر حاسد إذا حسد) 2015-05-01 05:44:19 +0500 #59

My problem .. system in my cycle is R-12, OLD school . cooling is 'just comfortably fine' but takes about 12 minutes cool down cabin after HOT MID DAY SUN open parking space.

according to sabir, change your parking place .. [ as if i have choice at every place i visit ]

suggestions please @ser_gtr, @syncview @xulfiqar

siraj_7 (siraj_7) 2015-05-01 20:32:56 +0500 #60

Vacuuming a system is not measured in time, it is measured in how much microns you want to pull.
There is a specific micron level at which all moisture boils and finds its way out of the system. The time taken to pull vacuum up till that level depends on the CFM capability of your vacuum pump, I saw a video on youtube where a tech pulled a 500 micron vacuum on a more than 5 ton aircon (imagine the size and length of pipes in that system) in 50 seconds!! with the proper tools. These guys don't have hours to waste on systems however he had a huge vacuum pump which was double stage I think
With the ordinary fridge compressor you cannot pull a deep vacuum to the required micron level even if you let the fridge compressor to run for days.
If you can't access a powerful vacuum pump, flush the system with nitrogen and then pull a vacuum and then just charge.
I read somewhere that this double technique works best where your vacuum pump is not capable to pull a deep vacuum to the level where all moisture (100%) will boil and find its way out of the system. So nitrogen is also a good way of driving the moisture out and then pull the vacuum with what ever your have.
Also make sure that from where ever you borrow the vacuum pump, ask that guy to change the oil of the vacuum pump, if the oil is transparent its fine, if its whitish...curdish sort then it is bad and the pump will not pull much vacuum, there is a glass window on the pump to see the condition of the oil.
In olden days, techs would nitrogen cycle and then pull vacuum as it was not possible to go below 2500 microns but with newer powerful pumps, techs pull up till 500 to ensure that all moisture is gone. However on some websites about HVAC I learned that it is not theoretically possible to remove all moisture with just vacuuming and nitrogen cycling is a must and so I found a third school of thought of techs who do both which is to Nitrogen cycle and then pull a 500 microns or below to ensure that their customer doesn't need repairs for the rest of the use full life of the HVAC.
Also if you have a micron gauge, or if your pressure gauge which shows negative pressure then you can test the system by leaving the vacuum (there is knob on vacuum pumps that turns the vacuum pump off and holds the vacuum) just leave the system for few hours to see if vacuum is lost, a very small (couple of 100 micron) loss is fine but if it is more than 1000 microns then there is a leak.
While finding a vacuum pump when I was to install Aircon in my room, I kept searching and searching and once contacted a vacuum pump machine supplier and he let me know about his customers who were car ac techs and his machine could recover/ pull vacuum / charge gas and play some more tricks for the car ac system. It was useless for me since I had to install a split and I have forgotten the names but those people were in Tariq Road Karachi.
I Alhamdullilah managed to do it as @xulfiqar had told which was to nitrogen cycle and then vacuum and then open the valves and believe me the results are great in terms of the less time taken to cool and better chilled air and less time in which compressor trips. Inshaa Allah I will be putting all the details on an aircon thread soon.