A/C Suddenly Not Working

[onespiritbrain]

So after I replaced my transmission my A/C no longer worked and before I started the transmission it was blowing very cold. The amount of time it was down was about 10 days including the time it took to locate a replacement trans.

 

So far I have:

1. Confirmed clutch is engaging.

2. Removed/flushed evaporator and cleaned/inspected TXV.

3. Evacuated, vacuum, and recharge.

4. Spun compressor clutch by hand, it has consistently smooth resistance.

5. 100% confirmed correct amount of refrigerant.

 

When I hook the gauges up I have the following pressures

 

AC off: H-110psi L-110psi

AC on: H-110psi L-90psi

 

Now when I bring the RPM up to 2500 the low side comes down to 80psi but the high side doesn’t move at all, not even a little bit.

 

Does anyone know about this stuff? I’m kinda stuck on it being an internal failure in the compressor.

 

 

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[jjonez]

Sorry in advance if this isn't helpful, but I didn't want you to be left hanging.

 

Based on my brief amount of research, it sounds like a weak compressor. When it switches on it should lower the low side pressure to around 30 psi and raise the high side.  This article seemed pretty informative to me.

 

Probably not a coincidence though that it was working fine before the new tranny.  Did the engine have to be moved at all to get it in?  Kinked hard line or something?  Spitballing here...

[Slartibartfast]

Also have a look at wiring for pressure switches and whatnot. I remember I somehow switched a couple plugs (one of them aircon related) on my friend's van when we were putting it back together, and the aircon didn't work until my friend figured it out. Hopefully Nissan didn't do what Chevy did and put two identical plugs next to each other.

[onespiritbrain]

Thank you fellas. I checked all the pressure sensors and every electrical part I could locate and I can’t seem to find any issue. The compressor clutch engages just like everything is normal but it’s just not compressing.

I am definitely leaning toward a badly worn compressor. It was taking forever to actually get cold before this happened. I say forever, about 10-15 minutes sometimes depending on how hot it was outside.

I put my hands on a compressor in a 2007 Nissan Maxima and it was probably ten times harder to turn the clutch by hand than mine is. I can spin mine around with one finger and I could barely move that one..

Later today I am going to the junkyard to find a good compressor. I know fall is coming but I still need AC for defrost and when it rains..

Thanks again yall


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[onespiritbrain]

Scored a compressor today woot!



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[onespiritbrain]

It was the compressor!

Oh man! It’s sooo nice! Can’t live without AC... haha


I think the whole issue might have been a lack of oil though... I filled the old compressor with iso100 turbine oil and it spit it out just like the new compressor. I have taken the AC apart so many times and each time a modest amount of oil comes out..

I will confirm this by putting my old compressor on the neighbors QX4

Wooh!!!!


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