Car AC Diagnosis of Various Symptoms Dedicated Thread

[Xulfiqar]

Update is. Opned the evaporation unit. Was clean and easy to flow. Txv was good. When I opned the compressor it was doomed it had slugged as filter says. Now I installed denso compressor picture attached. Cooling is nice after adding by weight. The thing is I see ice on my return line. What is that ? Even in the hood.

I pulled vacuum with .75 ton compressor for 15 minutes reaching 29 hg approx and mechanic was sir g tusi pagal ho....... Do you think txv is freezing? Low side is 35+ and high side is 300 at idle temperature is near 40 humidity is there as it rained yesterday

cool, you should have used a 60,000 BTU compressor to pull the vacuum, then ask the mechanic on whats going on.

[wasim625]

@xulfiqar
So umm after reading around on the internet for 3 days i finally concluded a method to tighten the belt.

Which is:
Press the belt from centre of the longest gap between the two pullies and place ruller and press the belt it should be not moving vertically more than 0.3 inches. (Approx.)

Is it ok?

[Xulfiqar]

@Xulfiqar
So umm after reading around on the internet for 3 days i finally concluded a method to tighten the belt.

Which is:
Press the belt from centre of the longest gap between the two pullies and place ruller and press the belt it should be not moving vertically more than 0.3 inches. (Approx.)

Is it ok?

thats a good way, its dependant on the distance between pulleys though. There is a tool to measure belt tension though. looks like a pliers but it has a gauge on it.

[wasim625]

thats a good way, its dependant on the distance between pulleys though. There is a tool to measure belt tension though. looks like a pliers but it has a gauge on it.

Sahi.
Tool added in 'To get Tools' list. Thanx paien

[afnan.bashir]

How did compressor ended up like that where does that slugg came from? Low oil or bad flush? mixing of different oils? Since evap and txv were fine Was it in condenser too?

At 40 it should be around low side 45.
You sure fan was at full speed and fresh air on recirculating?

Where you get your AC work done by the way? (Me too from Lahore you can tel me exact location since a friend of mine wants his Accord CL9 AC system overhaul)

Shadewal chowk Johar Town. Make sure when he comes you give me a call. Ill make sure the mechanic does everything to charge by weight and ill force him not to charge by liquid as he always do

[afnan.bashir]

suction line has ice?
measure superheat .. your superheat should be -14 to -6 Celsius if it's lower than -14 you're probably flooding your compressor with liquid

you just need to make sure that the txv is controlling refrigerant as it should and not letting more than the evaporator can handle

it may as well be possible that the heat load at your evaporator is low.. clogged evaporator fins or bad blower

if all above is well frost on suction line is nothing to worry about

Well bad thing is thermometer broke so cant measure temp. Evap is very free flowing. Fins are very clean and not damaged.

[afnan.bashir]

the frosting on the line is dependant on how much and where is this frosting. if its about 3 or 4 inches from the txv suction outlet on a humid day with controlled superheat then its probably ok. Apply some silver tape to it. This frost should be slight only, if you touch it, your finger should not stick. If its an iceblock - your compressor will have its janaza soon.

the oil sludge is formed by mixing wrong oils - it can gel up and cause all sorts of headaches.

Well from firewall there is just water drops that constantly fell off the suction line on engine. At driving side where engine is a but away from the line very thin ice can be felt and it goes till rubber part of suction line. that rubber pipe also has sweating

High side is not by the way.

No fingers do not stick. When i flushed the oil of this compressor i saw the reason for not flushing previous compressor caused the problem. I flushed the compressor with oil three times.

However i am looking for new thing that intermittently i get hunting idle on AC when i go to stop and it will go from 600 to 900 one or two times and then stablize. My friend has this thing too and his cl7 AC is OEM yet.

[afnan.bashir]

cool, you should have used a 60,000 BTU compressor to pull the vacuum, then ask the mechanic on whats going on.

Is there any relation betweeon BTU and CFM? and what recommended stuff is for AC Pumping? He just says ap anokhe he ho no one does vac for more than one min.

By the way when everything was put in place , before vacum i filled the system with nitrogen to absorb the moisture and also check the leak. when you vac you cant remove entire content. so instead of air i have nitrogen may be in my system.

As from the major i bought this car he was crazy about filling nitrogen in my cars tire. he says fuel economy increase

[Xulfiqar]

Is there any relation betweeon BTU and CFM? and what recommended stuff is for AC Pumping? He just says ap anokhe he ho no one does vac for more than one min.

By the way when everything was put in place , before vacum i filled the system with nitrogen to absorb the moisture and also check the leak. when you vac you cant remove entire content. so instead of air i have nitrogen may be in my system.

As from the major i bought this car he was crazy about filling nitrogen in my cars tire. he says fuel economy increase

The only reason to use nitrogen in the AC system is that its dry gas - I have also used CO2 in an AC system to test for leaks under pressure, its pretty easy with nitrogen, you attach the unit and open the valves.

For vacuuming I prefer a 2 stage vacuum pump, you can actually see steam ejecting from it (that is the moisture from the unit). And leave it for about an hour, it pulls a nice deep vacuum. If your AC mechanic questions you on this then either he has never took a class in physics or is just winging his business along. His business will end shortly.

[margallar]

The only reason to use nitrogen in the AC system is that its dry gas - I have also used CO2 in an AC system to test for leaks under pressure, its pretty easy with nitrogen, you attach the unit and open the valves.

For vacuuming I prefer a 2 stage vacuum pump, you can actually see steam ejecting from it (that is the moisture from the unit). And leave it for about an hour, it pulls a nice deep vacuum. If your AC mechanic questions you on this then either he has never took a class in physics or is just winging his business along. His business will end shortly.

what is the point of a Nitrogen, why not just let it achieve the required vacuum and then leave it for a while to see if it loses the vacuum

[syncview]

when you rip everything apart and fit it's best to perform a leak test using nitrogen

[wasim625]

when you rip everything apart and fit it's best to perform a leak test using nitrogen

Self edit

[afnan.bashir]

@xulfiqar how that silver tape is going to help? i was thinking of wrapping low side and high side pipes with aluminium foil so that heat that condenser has failed to shed gets away by low side cool pipe. what do you say? even if i dont use aluminium can i use any other thing do dissipate the heat ?

[SER_GTR]

Well from firewall there is just water drops that constantly fell off the suction line on engine. At driving side where engine is a but away from the line very thin ice can be felt and it goes till rubber part of suction line. that rubber pipe also has sweating

High side is not by the way.

No fingers do not stick. When i flushed the oil of this compressor i saw the reason for not flushing previous compressor caused the problem. I flushed the compressor with oil three times.

However i am looking for new thing that intermittently i get hunting idle on AC when i go to stop and it will go from 600 to 900 one or two times and then stablize. My friend has this thing too and his cl7 AC is OEM yet.

A/C System Kuch Ziada He Acha Hogaya... Check the Readings...Little Icing Is Ok But Too Much Is NO NO...Danger To Compressor..Al-Fatiha Alert.....

0.75 Compressor Can Pull How Much Vacuum = 3 CFM Vacuum Pump....Can Be Compared When You use Them And Feel Suction..

You WILL NEVER Get Good Suction From These Compressor As They Are Not Vacuum Pumps ...

Nitrogen Is Good For Removing Any Moisture In Line If You Have Maathaa Vacuum Pump As Like Your Mech Have ....!

Else A Good Vacuum Pump Vacuums Deep Remove It All W.o Any Issues....Unfortunately I Never Came Across Any AUTO A/C Shop Or Even Commercial Installers (SPLIT) Type Who Use Vacuum Pump....

[SER_GTR]

@Xulfiqar how that silver tape is going to help? i was thinking of wrapping low side and high side pipes with aluminium foil so that heat that condenser has failed to shed gets away by low side cool pipe. what do you say? even if i dont use aluminium can i use any other thing do dissipate the heat ?

Keep Your High Side Line From Comp To Condenser OPEN...Wrap Suction Line..You Can Use A/C Insulation Pipes Available And Tie Clip Them

[Xulfiqar]

what is the point of a Nitrogen, why not just let it achieve the required vacuum and then leave it for a while to see if it loses the vacuum

an AC runs under pressure not vacuum, its sealing parts are designed for pressure, I have run across some real goofy issues where the system held vacuum but was losing pressure.

[afnan.bashir]

Keep Your High Side Line From Comp To Condenser OPEN...Wrap Suction Line..You Can Use A/C Insulation Pipes Available And Tie Clip Them

Thing is what if I cover high side and suction after condenser will any removed heat from high side contribute to better efficiency.

Why do I get all the fishy issues. When I turn on AC and when compressor engages it drops 3-400 Rpm but ok engine tries to manage it but simultaneously it starts putting load till rpm gets so low and ECU turns it off and then 're engages. This goes on untill I press throttle and help compressor engage

[wasim625]

Isn't your ride getting a money pit now
A good case study for people like me to learn by the way lol

[Xulfiqar]

never cover the high side, its shedding a little bit of heat as it goes to the txv, If it comforts you then add a layer of insulation to the low side, but it wont be substantial.

for the loading up, remove some refrigerant from it and retest. Not more than 20 grams

[SER_GTR]

Thing is what if I cover high side and suction after condenser will any removed heat from high side contribute to better efficiency.

Why do I get all the fishy issues. When I turn on AC and when compressor engages it drops 3-400 Rpm but ok engine tries to manage it but simultaneously it starts putting load till rpm gets so low and ECU turns it off and then 're engages. This goes on untill I press throttle and help compressor engage

Compressor Load Means Overfill Ref.....Dropiing Is Due To Load On Engine On Idle Which Lead To RPM Drop And ECU Turns It Off...When They Get Normal ECU Engages As You Throttle UP... It SHld Never Take Such Load On IDLE....!