Car AC Diagnosis of Various Symptoms Dedicated Thread

[ahsanonline]

Pully and tensioner both look fine. Few months ago I had to get some refrigent refilled and went to a guy known for good work he filled in Gas and when the compressor engaged he was like oh its making noise he suggested I should have opted for Sanden compressor and we can change this into that than when he looked at guages (Low side was near 30 on idle RPM)and he said well to be honest this one is working very nicely and other than a bit noise no issues. :p. I just feel its put load on engine (My Engine is 7AFE 1800CC) though cools fine infact If i compare with a brand new corolla in Office my AC Kicks in and cools way faster.

A compressor starved of refrigerant will also put excessive load on engine. You need both low & high side readings (on both idle and 1500rpm speed)+ambient temp to determine approximate state of charge.

[Vaqas1]

A compressor starved of refrigerant will also put excessive load on engine. You need both low & high side readings (on both idle and 1500rpm speed)+ambient temp to determine approximate state of charge.

You have the guages :p. Maybe you can see how its running some day.

[afnan.bashir]

@xulfiqar how do you clean txv? Do you spray ctc there ? And then blow air out of it ?

[syncview]

you can do that too.. bit have to make sure you get it all out

[DUDE007]

My car's compressor fuse melts whenever the ac is on. Its a 20A fuse and wiring is ok. The piece of glass on the silver cylinder thingy shows some white gas flowing. What could be the problem?

Edit: i dont have a dc clamp meter...

[Xulfiqar]

@Xulfiqar how do you clean txv? Do you spray ctc there ? And then blow air out of it ?

I never suggest to clean a TXV unless its a TXV that can be broken down (very old cars had those brass items)

[Xulfiqar]

My car's compressor fuse melts whenever the ac is on. Its a 20A fuse and wiring is ok. The piece of glass on the silver cylinder thingy shows some white gas flowing. What could be the problem?

check the resistance of the magnet of the clutch and its gap to the pressure plate too. Average dumb Pakistani AC mechanic wont be able to understand this.

[DUDE007]

check the resistance of the magnet of the clutch and its gap to the pressure plate too. Average dumb Pakistani AC mechanic wont be able to understand this.

This went over my head [emoji14]
How is this related to clutch?
Where is the magnet located? How do i check the gap?

[Xulfiqar]

Pully and tensioner both look fine. Few months ago I had to get some refrigent refilled and went to a guy known for good work he filled in Gas and when the compressor engaged he was like oh its making noise he suggested I should have opted for Sanden compressor and we can change this into that than when he looked at guages (Low side was near 30 on idle RPM)and he said well to be honest this one is working very nicely and other than a bit noise no issues. :p. I just feel its put load on engine (My Engine is 7AFE 1800CC) though cools fine infact If i compare with a brand new corolla in Office my AC Kicks in and cools way faster.

Denso 10PA starts with a slight noise which goes away after a few seconds I have always experienced it in old compressors. And when your tech said to install a sanden unit to rid of noise, its kind of wrong as any sanden compressor has a permanent humming sound even when brand new out of box.

[Xulfiqar]

This went over my head [emoji14]
How is this related to clutch?
Where is the magnet located? How do i check the gap?

there is a clutch on your compressor, its activated by a magnet coil which pulls in the pressure plate on the compressor which starts rotating the compressor.

That magnet coil requires power to generate a magnetic field. If the gap is too large the pressure plate will skip on the pulley and overheat the magnet sometimes shorting the winding. I would not suggest you do this unless you fully understand what this is.

Reason to say not to DIY is that if you accidently damage a line in the AC system - it can give you instant frost bite - if it blows near your face you will be blinded permanently as the AC gas can freeze your eyeballs dead.

[DUDE007]

I will do research on this. what a deadly diy....

[DUDE007]

@xulfiqar one more thing......the compressor takes some time(1 -2 seconds) to enagage. Is this a sign of a bad clutch or increased resistance?

[Xulfiqar]

@Xulfiqar one more thing......the compressor takes some time(1 -2 seconds) to enagage. Is this a sign of a bad clutch or increased resistance?

can be either.

but please enlighten on what do you mean by takes time? does the compressor slip?

[margallar]

and then you realize how hazardous the life of a mechanic is. i am surprised how people are unaware of the risks they take...inhaling petrol, grease/ motor oil over their skin, carburetor cleaner (which i think kills your grey matter)...........

[afnan.bashir]

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

[wasim625]

there is a clutch on your compressor, its activated by a magnet coil which pulls in the pressure plate on the compressor which starts rotating the compressor.

That magnet coil requires power to generate a magnetic field. If the gap is too large the pressure plate will skip on the pulley and overheat the magnet sometimes shorting the winding. I would not suggest you do this unless you fully understand what this is.

Reason to say not to DIY is that if you accidently damage a line in the AC system - it can give you instant frost bite - if it blows near your face you will be blinded permanently as the AC gas can freeze your eyeballs dead.

Dannnmmm!!!
I am never opening hood of my car ever again :||
Lol

[wasim625]

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

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)

[DUDE007]

can be either.

but please enlighten on what do you mean by takes time? does the compressor slip?

I don't know what slipping sounds/looks like but rpms rise a lot when ac is turned on. Ac idle rpm was set same as normal idle speed. When I'm decelerating, the car accelerates a bit as the compressor is on then it engages and car decelerates

[syncview]

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

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

[Xulfiqar]

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.