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Mike V.
Mike V., Infiniti Mechanic
Category: Infiniti
Satisfied Customers: 25687
Experience:  Factory trained to repair Nissan and Subaru.
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I have a 2008 infiniti qx56 (140,000 miles) lost my ac,

Customer Question

Hello, i have a 2008 infiniti qx56 (140,000 miles) lost my ac, started trouble shooting, compressor was not engaging. The clutch was getting voltage but not engaging. Replaced the compressor (appeared to still be in really good shape, looks like it was just a clutch failure) thought i could get by just replacing the compressor. After pulling a good vacuum the system was recharged. But the high/low pressure is always the same. Its pointing to a expansion valve problem possibly. If you agree the next thing is how bad is this to replace. I have the glove box removed and looking at what may lay ahead i thought i would seek out some help/advice.
Submitted: 1 year ago.
Category: Infiniti
Expert:  Mike V. replied 1 year ago.

Hi there,

Just to be clear here, the compressor is working now?

Customer: replied 1 year ago.
the compressor is working.
Expert:  Mike V. replied 1 year ago.


What I would do is if possible tap the area of the valve with a small hammer and see if it changes anything. I am looking for info on the expansion valve for you, but try the tapping and see if the pressures change at all. I have in the past broken them free with a little tapping. I agree this is the likely problem as long as the new compressor is good. If the pressure isn't getting high then it's quite possible the new compressor isn't pushing the freon.

Please give me a few to see what I can come up with for the expansion valve for you.

Customer: replied 1 year ago.
The expansion valve appears to be buried pretty good (behind glove box area) Another thing that concerns me is that there is suppose to be two expansion valves on this system. And if there is any way of determining which one may be messed up. Have not even attempted locating the rear one. I will go take another look at the front one again and see what i can find (if i can possibly tap on it) A little extra info on the pressures also, it was getting to around 110 (both sides) it does cool the air but very very little. The compressor never cycles, stays engaged
Expert:  Mike V. replied 1 year ago.

I'm sorry, 2 different manuals, one the factory manual and nothing in there on the expansion valve replacement.

It is buried in there and sadly, at least on my last experience with this, I had no luck sneaking it out the front by removing the bolt. A lot had to come out to move it enough to get it out. The hole in the firewall isn't large enough to get it out of the front.

Curious about your pressure, what is it with the engine off? Perhaps the pressure you are reading is just the freon itself and the new compressor isn't doing it's job. I would say if the pressure is close to that 110 psi with nothing on, you might have a bad compressor. If that's the case try that before going after that H valve.

Customer: replied 1 year ago.
Okay, let me go check my pressures. Will get back with you shortly.
Expert:  Mike V. replied 1 year ago.

Sounds good. Might save a whole lot of hassle!

Customer: replied 1 year ago.
Well just hook the gauges back up. The has not been started for at least 20 hours and i still have the same pressures. You think i may have a bad new compressor?
Customer: replied 1 year ago.
Oops i left "vehicle" out of the last message at the start of the second sentence
Expert:  Mike V. replied 1 year ago.

Yeah, it looks it to me. You have equal pressures and the compressor hasn't even been turned on. This is probably just the pressure from the gas in there and the ambient air temp. My money is on a bad compressor. Typically even if it had a bad H valve, it would at least show some pressure difference hi to low and certainly a ton of pressure on the high side if it can't get through there. I do think you have a compressor issue and would replace it again before taking the dash apart here.

Please let me know what more I can do to assist you today. Also, please remember to rate my answer, Just Answer does not compensate me for my time and resources. Follow up questions are included in the price of your question. If you are using the free trial, or have a subscription a rating is still required.
Thank you so much!