A/C Compressor / cooling system questions - dead ac

[bpomps]

2000 maxima
so my compressor started making loud noises a few days ago but would go away when i turn on the ac. a few days later (now) the compressor is very loud and the ac blows hot air. i hooked up a gauge on the low pressure to charge it and it reads in the red zone and wont take any 134 or oil.

im wondering if its just my compressor dying / dead or if it could be something else.

if i change out the compressor do i need to change any other part -- ive read some say yes and some say no on the condenser. just trying to get this fixed cheap as i can change out the compressor myself - if thats the issue.

[MinisterofDOOM]

With the thing making noise, my first guess would be the A/C clutch is bad, so the compressor is never actually engaging.

[loystock]

The 'Minister' is correct, based on your symptoms. But of course, the compressor could also be bad. You have to do more diagnostics to confirm. BTW, given the right tools (may be borrowed from Autozone), the clutch assembly can be replaced without breaking the AC line, not true with compressor replacement. There are several postings on how to do it - SEARCH.

Below are on-going forum discussions about AC problems:

post5671343.html#p5671343

a-c-expansion-valve-t497968.html

[bpomps]

i forgot to mention that the 10A mini fuse was blown so i replaced it, turned on the AC and it worked, was quiet and blowing cold air - for about 2 or 3 minutes and the fuse blew. how can i tell if the other larger blue relay (4 prong fuse block) on the other side is shot ?

im planning on trying to get those tools this weekend to maybe figure it out.

[NutriaforBreakfast]

For 2000 Maxima looked in the HA section on page 111
http://www.nicoclub.com/FSM/maxima/2000/ha.pdf
Is the high side of the compressor 85 PSI? If PSI too high, the fuse
may have blown to protect the system from damage
Both the low side and the high side have an optimal PSI for the system to work

[bpomps]

gonna check it out this weekend. thanks!

[enduroexpertfsr]

sounds like your clutch is gone. i work on a/c for a living. if im gonna go through the trouble of changing a clutch. im changing the whole compressor.

[bpomps]

sounds like your clutch is gone. i work on a/c for a living. if im gonna go through the trouble of changing a clutch. im changing the whole compressor.

yea, im planning on changing the compressor. hopefully thats the only problem

[enduroexpertfsr]

when you have someone recover the refrigerant, and you remove the compressor, drain the oil out of it, if its dark or grey, i would highly recommend a complete system flush and a new expansion valve/orafice tube. aswell anytime you open the a/c system to atmosphere you need to change the reciever drier/accumulator tank

[bpomps]

when you have someone recover the refrigerant, and you remove the compressor, drain the oil out of it, if its dark or grey, i would highly recommend a complete system flush and a new expansion valve/orafice tube. aswell anytime you open the a/c system to atmosphere you need to change the reciever drier/accumulator tank

i am replacing the compressor, drier, expansion valve and orings. once i replace these items and have them on, is it just charging up the system with 134a and you are done ?
im waiting for the parts to get here next week, since the compressor is shot - is it ok to drive the car ? i mean its kinda loud but im ok with it but im wondering if at some point its going to lock up ???

[NutriaforBreakfast]

You can drive the car without using the AC pulley if you can find a belt to fit.
If you got some string and wrapped it around all the pulleys except the AC pulley
you could give Auto Zone or whoever the measurements and they might be able
to get a substitute belt.

Some AC compressors come with a new clutch and others dont. You will need
to verify

[bpomps]

How does the belt tension pulley work on the 5th gen? .
Ive dealt with the auto kind on an o4 altima but the one on the 00 max looks like it has a main bolt to move it around?

[bpomps]

so im stuck and hope someone can help.....

replaced the compressor and drier (and belt). did the vacuum and charge it up with some pag and freon. blew cold for about 20 mins and now its blowing hot air.

theres pressure in the lines (its holding freon) and there doesnt appear to be any leaks that i can see

any help ?

[loystock]

Did you change the expansion valve? Did you you PAG46 oil? What's the pressure for the High and Low side after 10 mins @ 1500 RPM? Is the low side tube very cold to touch (or frosting near evap)? Can you see refrigerant flowing from a sight gauge on top of drier?

[bpomps]

Did you change the expansion valve? Did you you PAF46 oil? What's the pressure for the High and Low side after 10 mins @ 1500 RPM? Is the low side tube very cold to touch (or frosting near evap)? Can you see refrigerant flowing from a sight gauge on top of drier?

i didnt change the expansion valve because the one on there looked ok - is it possible that it can look ok but still be bad? i mean on the inside.

i used a little bit of PAG100 - because the auto parts store's computer said thats what to use with the aftermarket compressor but not much went into the system

the low side was cold when it worked for the first 20 mins or so and now its normal temp - no frosting.

i had the gauges hooked up but dont remember the reading - they werent even, i remember that. ill have to redo the reading. there was refrig flowing through the little glass valve on the gauges.

[loystock]

The expansion valve could be stuck open which allows the system to initially blow cold air but then the evaporator eventually freezes. Other possibilities are debris in the system which clogged the expansion valve and other components or contaminated (water vapor) refrigerant which freezes when the system gets cold.

You need to record the Hi/Lo pressure reading when it's blowing cold air and hot air.

[bpomps]

The expansion valve could be stuck open which allows the system to initially blow cold air but then the evaporator eventually freezes. Other possibilities are debris in the system which clogged the expansion valve and other components or contaminated (water vapor) refrigerant which freezes when the system gets cold.

You need to record the Hi/Lo pressure reading when it's blowing cold air and hot air.

im gonna change the expansion valve and do another flush while i still have the tools.

the screw on the expansion valve is stripped and ill have to drill it out - - do you happen to know the size of the screw that the expansion valve uses to mount to the evap?

[bpomps]

Is this a good reading ? its +45 on the Red and about + 2- on the blue

[loystock]

You got me so confused with the reading. What you posted, +2 and +45, are the saturation temperature in degrees Centigrade for R134A refrigerant, not the pressure. You have to read from the inner scale, in PSI. I'm glad you posted the image of the gauge so now I can make sense out of it. So based on those readings your Low side (Blue) is @ 31 PSI and the High side (Red) is @ 155 PSI. The spec at 86F OAT is 31-37 PSI for Low side and and 149-185 PSI on the High side. So assuming the ambient temperature is around that value when you took the measurements, then your compressor is running at the correct pressure. Make sure you take new readings when, and if, the AC starts blowing hot air again.

Please refer to page HA-86 to the FSM link provided by 'Nutria.' It shows the chart for Relative Humidity, Ambient Temperature (or OAT) and the corresponding Low and High side pressure window.

[bpomps]

You got me so confused with the reading. What you posted, +2 and +45, are the saturation temperature in degrees Centigrade for R134A refrigerant, not the pressure. You have to read from the inner scale, in PSI. I'm glad you posted the image of the gauge so now I can make sense out of it. So based on those readings your Low side (Blue) is @ 31 PSI and the High side (Red) is @ 155 PSI. The spec at 86F OAT is 31-37 PSI for Low side and and 149-185 PSI on the High side. So assuming the ambient temperature is around that value when you took the measurements, then your compressor is running at the correct pressure. Make sure you take new readings when, and if, the AC starts blowing hot air again.

Please refer to page HA-86 to the FSM link provided by 'Nutria.' It shows the chart for Relative Humidity, Ambient Temperature (or OAT) and the corresponding Low and High side pressure window.

yea i was reading the outermost black dial on the gauges - thanks for the page # link.