Car AC Diagnosis of Various Symptoms Dedicated Thread

[afnan.bashir]

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

Well if your system is doing good then i think only option we are left with is first to open windows and drive car like that this will allow hot air inside oven like car to go away. Eventually AC can work easily. but i think 12 min is sort of too much...... you have townace?

[afnan.bashir]

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

So conclusion is Fill the system with Nitrogen and then vac?

[SER_GTR]

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.

In A Nutshell They Don't Even Have A Proper Vacuum Pump To Pull A Vacuum...Micron Gauge LOL

Nitrogen Removes Most Of Moisture ALong With It By Absorbing...Its Recommended When You Flush Parts....

Our Country Have High Humidity Specially KHI So Moisture Is Needed To Be Removed Its A Killer Of You A/C Performance

[SER_GTR]

So conclusion is Fill the system with Nitrogen and then vac?

Nitrogen Removes Moisture From System Along With It....On Cars....When You Flush Lines Condenser You Can Use It As An Additional Stuff..

Its Required Mostly In System Where Deep Vacuum Takes A Lot Of Time...Eg SPLIT Type With Outer Placed Far Away.....Longer Lines so Line Length Matters

Mostly In Car A/C System...We Don't Have Longer Lines So A Deep Vacuum Which Will Be Like 38-45min Along With Receiver-Dryer Change Can Do It All Good

[SER_GTR]

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

Use Sun Shades On Wind Screen Side Windows

If You Can Do....I Have Seen People Removing Roof From Inside And Place An Insulation As Layer So Heat Won't Get Inside Car Easily

This Way Your Car Won't Heat That Much.....Just Pull Windows Down...Let Hot Air Pass And Trigger A/C....You SHould Feel Diff ...

[siraj_7]

@afnan.bashir, yes connect the guauge, fill the system with nitrogen and let it flush for few seconds and then close the valve (with nitrogen still present inside) for some time and check for any drop in pressure on the pressure gauge (when I checked my system it was 150 psi on the guage and I let it for 10 minutes). Then if every thing is fine and there is no leak then pull the vacuum and then let the vacuum stay for a while and check if there is any drop in negative pressure on the guage and if no leak is found then charge the system. My AC wala had a set of tools with multiple nipples and many things at once could be connected and there were knobs to lock each component connected. The idea is to ensure that once nitrogen, the vacuum is pulled on the same nitrogen and then on the same vacuum the gas is charged so air never finds its way out because if you have only one port and keep connected and disconnecting things on it such as nitrogen cylinder and vacuum pump and then your gas cylinder then there is no use doing all this excervise.

By the way during my survey I found that all ac walas have a big nitrogen cylinder in their shops and they are just lazy. If you press him to get it done the proper way he will do it.

[siraj_7]

Please read my previous post again. As I have mentioned a deep vacuum can not be pulled with a fridge compressor even if you let it on for days. It just doesn't have the power to do it, a 15 minute 500 micron vacuum might be possible with a 5 cfm double stage pump but not a fridge compressor so its better to nitrogen cycle and then vacuum with whatever you have (small pump or fridge compressor) ...

Nitrogen Removes Moisture From System Along With It....On Cars....When You Flush Lines Condenser You Can Use It As An Additional Stuff..

Its Required Mostly In System Where Deep Vacuum Takes A Lot Of Time...Eg SPLIT Type With Outer Placed Far Away.....Longer Lines so Line Length Matters

Mostly In Car A/C System...We Don't Have Longer Lines So A Deep Vacuum Which Will Be Like 38-45min Along With Receiver-Dryer Change Can Do It All Good

[siraj_7]

Also check the ambient temperature and see the chart of high and low side pressure for that ambient temperature range for the gas you are trying to charge (google the chart, I have seen it on the thread of agoodfriend – cultus overhaul), this is best approach if you don’t know the weight needed for your system or if the length of pipes and size of condenser, evaporator have been changed from what was stock. In altering the stock system the weight mentioned on the sticker will not be relevant any more. Good luck with your expedition.

[capsat]

Thank you ALL ! - 12 Minutes when outside temp is soaring 40+

[SER_GTR]

Please read my previous post again. As I have mentioned a deep vacuum can not be pulled with a fridge compressor even if you let it on for days. It just doesn't have the power to do it, a 15 minute 500 micron vacuum might be possible with a 5 cfm double stage pump but not a fridge compressor so its better to nitrogen cycle and then vacuum with whatever you have (small pump or fridge compressor) ...

I Know A Fridge Compressor Won't Pull It...I Am Talking About 3 CFM Vacuum Pump ...I Use It

[SER_GTR]

A Productive Sunday

After A Long Time I Am Posting My DIY Images On PW....DOn't Remem When I Did It Last Time

Got Quick Couplers & Refrigerant Last Night....Installed Gauges Today And Found That System Was Not Empty There Was Charge In It But Quiet LOW....So I Decided Not To Mess With Anything But Charge It.....

It Was Almost 35-36 Degrees Celsius Ambient With Like 30-40% Humidity ....As Per Chart 40-45Psi Low And 155-210 Psi On High For This As Per Chart

I Get Like 40Psi LOW And 190Psi High...On Revving High Side Goes Till Like 210-220 And Fan Speed Kicks In And It Goes Back To 200 Around......So It Was Good

Condenser Right Side Front Fins Were Bit Bend But Right Side Where Pressure Side Comes And Where Fan Is Installed....It Was All Clean... Back Side All Clean....So I Clean It With Blower Then With Low Mid Water Pressure.....!!

Lets See How It Goes..... Might Flush System Completely When 2015 Summers Are Over Nice And Easy...If They Do....!

[SER_GTR]

Forget To Mention Vent Temp....It Was Touching Like 13 Degrees......Fair Enough ....Maybe It Gets More Better Now After I Clean Condenser And As System Runs

[salmanrasheedpsh]

hope this is the appropriate thread
my car , 2nd gen vitz
its ac has good cooling
but as the compressor trips after reaching desired cooling , the air doesnt remain cool for long enough , quite soon just in 10 15 seconds it gets hot and humid ,
dat didnt happen last summer
is sumthing wrong wid my car ac system ?

[SER_GTR]

Its Just Temp Or You Car Being In Too Much Heat

Nothing Wrong With System If Its Tripping And Engaging On Proper Time

Best You Can Do Is Keep Temp Gauge Inside Car And Note Its Tripping Temp And Trigger Temp

[Hashim11]

Its Just Temp Or You Car Being In Too Much Heat

Nothing Wrong With System If Its Tripping And Engaging On Proper Time

Best You Can Do Is Keep Temp Gauge Inside Car And Note Its Tripping Temp And Trigger Temp

How much that guage costs? And can that guage can be used with other A/C like split ac?

[SER_GTR]

Its A Universal Gauge Used Anywhere

You Can Measure Room Temp Car Cabin Temp...

There Also Comes Probe Type Which Can Measure Probe Temp Too If You Place Probe Outside....

It Cost From 100-1000/- Depending On What Kind You Want

Digital Is Expensive Like 500-1500 Depending on quality

You Can Also Get Old Glass Type Mercury ...It Also reads Accurately & Fast But Need To Be Handle With Care

[Hashim11]

A Productive Sunday

After A Long Time I Am Posting My DIY Images On PW....DOn't Remem When I Did It Last Time

Got Quick Couplers & Refrigerant Last Night....Installed Gauges Today And Found That System Was Not Empty There Was Charge In It But Quiet LOW....So I Decided Not To Mess With Anything But Charge It.....

It Was Almost 35-36 Degrees Celsius Ambient With Like 30-40% Humidity ....As Per Chart 40-45Psi Low And 155-210 Psi On High For This As Per Chart

I Get Like 40Psi LOW And 190Psi High...On Revving High Side Goes Till Like 210-220 And Fan Speed Kicks In And It Goes Back To 200 Around......So It Was Good

Condenser Right Side Front Fins Were Bit Bend But Right Side Where Pressure Side Comes And Where Fan Is Installed....It Was All Clean... Back Side All Clean....So I Clean It With Blower Then With Low Mid Water Pressure.....!!

Lets See How It Goes..... Might Flush System Completely When 2015 Summers Are Over Nice And Easy...If They Do....!

I am asking for this guage.

[SER_GTR]

I am asking for this guage.

Its Called Manifold Gauge Set ....It Will COst Around 1500--2500 Depending On Quality And Origin...USA Or Branded Cost More Than 2500

Yes It Can Be Used With Split Ac Also....

To Use It On Automobile R134a System ..You Need Couplers Also Which Will Cost Under 1000/-

[siraj_7]

@ser_gtr you got 3CFM vacuum pump and you are in Karachi.. wow you are a man of great interest to me

Bro how much did you get the pump for? dealers here are asking too much for vacuum pump...and I see your manifold guage shows negative pressure as well so you pull vacuum and see if your system holds vacuum for long just incase it develops a leak and you fix it and then you can check. It will not be 10% of what a micron guage can do but still it will be good. and next time your R134a cylinder goes empty get it flushed and get it filled with nitrogen. It will work wonders you can become an AC tech over night

[siraj_7]

@ser_gtr don't worry about bent fins, search you tube, with a fin comb you can fix it with 1 stroke of a hand. Its just that the comb has to be perfectly sized with the gap between fins. Just incase you don't get your hands on to anything from the market an anti-lice comb can all be used to fix it.