Why won't my 91 circulate the A/C freon?

[Greg Z]

I bought a 91 that has only had 4k put on it in the last 2 years from Northern Cali., and the A/C does not blow cold at all. I had a mechanic try to charge the system but it won't take any freon, actually he says the system has a good amount in it already(I think he said 80 to 90 lbs.). But, it will not take any more because the freon is not circulating at all. The compressor IS kicking on. I repeat it won't take any new freon at all. Is there some sort of valve stuck somewhere?

 

[zahntech]

I think you need a new mechanic:wink: the system holds a max of 2.3lbs and if the compressor is ingauging than you should have curculation or the pressures will tell you what the problem is.

What are the high and low side pressures when the system is running?

 

[Greg Z]

He was putting gas in the big line and I'm sure he said something about 80 or 90 on his guage. He said something was keeping the gas from circulating and taking any new freon in the system. He double check his hoses and connections and all was fine. He said run the A/C ON on the way back to Louisiana and amybe it will break loose and start blowing a lil cold because there was freon in the system. But it did not!

 

[drew]

It sounds like it might be a blocked expansion valve. You can gain a view of it by removing the blower assembly under the hood.

I think your choices are 1) become an expert in the NSX a/c system or 2) pay several thousand to get it fixed.

there is a lot of info in these forums on your issue.

drew

 

[Big_D]

Dang, the honeymoon is over already...those pesky a/c issues we all seem to have from time to time. My a/c works on manual but not with the auto climate control. Have you tried it with just manual fan settings?

 

[ediddynsx]

Welcome to owning a 15 year old car....expect things needing to be replaced. Remember time is also a factor with wear not just mileage. The car is 15 years old and parts don't last forever. I am still surpised though how awesome the car is after so many years. I know some of my previous cars would not have lasted this long.

So far I am lucky that everything works fine on my car but who knows down the line. Sorry to hear about your issue I would suggest you consult with a factory certified NSX technician from Acura. Or if you know a independent shop that has a lot of knowledge about the NSX.

Luckily for us here in Calif we have Jon Martin at Cerritos Acura and various other alternatives.

 

[zahntech]

He was putting gas in the big line and I'm sure he said something about 80 or 90 on his guage. He said something was keeping the gas from circulating and taking any new freon in the system. He double check his hoses and connections and all was fine. He said run the A/C ON on the way back to Louisiana and amybe it will break loose and start blowing a lil cold because there was freon in the system. But it did not!

If your getting 80 to 90 psi on the low side (larger hoses) than your expansion valve is not restricting the flow enough, the low side should be approx 30psi and the high side appox 150psi.

If the expansion valve is pluged, the low side will get sucked down to a vaccum.

We need to know the High and Low side pressures to attempt to Diag the problem.

 

[RON98]

:smile: lol i was reading that too. 90 psi on your low line is a no no.


The typical PSI on the low side should be about 30-35.... i keep mine at about 27.... cause im stingy and it still blows cold.

At 30psi on the low side, the high side should be about 150-200psi.... off the top of my head and should never exceed 250, at which point your compressor is going to be doing damage to it self.

I would do a complete vaccum on the system, take out everything, recharge with 2 ounce of oil and 2 cans of freon. If the A/C compressor does not engage due to low freon when you vaccum everything out ( the vaccum should acturally be sucking in the freon and oil but the ac compressor does a can in about 2 seconds :biggrin: ) you can hot wire the a/c clutch to a 12 volt.

you can do everything yourself from home for pennies on the dollar of an A/C service.

You'll need, a compressor, a/c manifold gauge, freon, 2 once oil and retrofit kit if your car is still R12.

All the tools should cost no more than about 250$ ... thats including a compressor as the main cost of entry.

a reading of both high and low would be great.

A/C service does not have to be expensive... its acturally very cheap and easy. Im not sure why its so expensive.... i guess people got morgages to pay:biggrin:

anyways, any one in socal need an a/c service thats not the "take you to the cleaners cause you have an nsx" price and a quick one at that, let me know. I'll personally do all the work.

 

[Greg Z]

OK thnx for the info, I'll be taking it to the mechanic as soon as I can bear to part with it for a lil while. Oh and remember, that wasn't my mechanic that did the work before, I was traveling though Phoenix and hired one.
If the oil does'nt loosen the expansion valve where is it and what is done to change it and how much?

 

[RON98]

the oil is not made to loosen up the expansion valve. its purpose is to lubercate the compressor pistons much like engine oil for our engines.

Does your a/c compressor cycle on and off repeatedly?

 

[RON98]

also does your engine rpm drop a lot when you turn on the ac? does the car seem to be struggling when the ac is on? Dramatic loss in power?

 

[RON98]

explansion valve is under the dash, on the evaparator core. You need to take out everything to get to it. :tongue:

 

[Greg Z]

also does your engine rpm drop a lot when you turn on the ac? does the car seem to be struggling when the ac is on? Dramatic loss in power?

No, No, No & No, to those 4 questions.
purchase just the exspansion valve from Acura?????????

 

[Daedalus]

I would wait until you have something a little more concrete than "something about 80 or 90 on his guage". If the tech working on the car couldn't say with certainty exactly what your car needed, probably best not to place a large bet on an educated guess from a web forum.

 

[Greg Z]

I would wait until you have something a little more concrete than "something about 80 or 90 on his guage". If the tech working on the car couldn't say with certainty exactly what your car needed, probably best not to place a large bet on an educated guess from a web forum.

I agree. I only asked that last question to get a feel if I was able to purchase JUST the expansion valve alone or was I going to have to buy it in a bigger part like an Evaporator or something. Also trying to figure out where to buy it, hopefully other place other than just Acura. I still like to know the answers?????????????

 

[drew]

I was able to purchase JUST the expansion valve alone or was I going to have to buy it in a bigger part like an Evaporator or something.

You can buy either part separately from Acura.

www.nsxpartsdb.com

Also trying to figure out where to buy it, hopefully other place other than just Acura.

There are aftermarket and OEM sources for these parts.

If you SEARCH the forums you will find that one guy has used an aftermarket evap with good results.

I still like to know the answers?????????????

Search the forums. These topics have been hashed many MANY times.

--discount parts source
--aftermarket evap
--a/c diagnosis and repair

Not only will you save yourself time and gain knowlege, but you will save your virtual friend's time too.

I caution you again, the NSX system can be EXTREMELY expensive to repair...in the several thousand dollar range. Half measures and insufficient knowledge will cost you dearly.

Drew

 

[53heloFE]

I agree. I only asked that last question to get a feel if I was able to purchase JUST the expansion valve alone or was I going to have to buy it in a bigger part like an Evaporator or something. Also trying to figure out where to buy it, hopefully other place other than just Acura. I still like to know the answers?????????????

Drew is right about being able to purchase the seperate parts. Generally if the epansion valve is replaced you will want to replace the reciever/dryer too. Have not had to replace an expansion valve on an NSX yet but I have done it on many other cars, just a pain to get to.

 

[bruckner]

Resurecting an old thread, I'm having similar issues but maybe not exactly the same. My mechanic emptied the system of refrigerent and when he tried to fill the system, the compressor was showing no negative pressure. We can hear it running, but it's not pulling anything... replace compressor? Or could it be the dreaded expansion valve that is blocking pressure? Any help appreciated.

 

[TomCat]

explansion valve is under the dash, on the evaparator core. You need to take out everything to get to it. :tongue:

You can go through the front firewall.

- - - Updated - - -

My a/c fix turned out to be a simple $100 dryer (it was old/plugged).