Hey guys. Just had a new compressor installed and the system evacuated and recharged. I used the AC for the first time today and noticed that after a little while, the air just trickles out of the vents. If i shut the AC totally off for a bit, then turn it back on, the air blows strong again, but begins to trickle again after awhile leading me to believe something is freezing up.

1st question....what is "freezing" up here?

2nd question....this is what my line looks like (bright white frozen) after 45 minutes of AC use. I am not an AC guy so any input will be helpful

 

Could be your expansion valve or evaporator.

Just googled your description and others have found these to need replaced.

I'm no pro a/c guy either though..just my two cents.

 

I came up with condenser when I searched. hoping someone can pin point exactly.

 

i would go back to where you had the work done.. im not an a/c person either, but that should not be happening.. they should be able to tell what is wrong by hooking up the real a/c gauge set. if your other compressor did go, there is a good chance (looking at that picture) that something has gotten into your system and clogged something up.. again - im not an expert, but i think when compressor's go its usually recommended that another part gets changed also, for that exact reason. i dont want to say which one, cause im not sure and i dont want to feed you wrong info..

 

I'll probably go back to them tomorrow (monday) but I didn't want to go in blind with them so I am hoping someone can steer me in the right direction before I go see them. Looks like I'll have to have the system evac'd again How can they tell if something is plugged up? I mean, I have to assume the pressures were right or they would have said something to me.

 

Thats the suction line, or low side. It gets cold, but usually just sweats. I bet the evaporator is frosted up just as bad so there is little air flow over it.

 

So does that mean I need a new evaporator or a new expansion valve...or both Jon?

I kind of figured the evaporator was getting frozen after a period of time which is why the air volume decreased after running it for a while. So just so i know, the air from the blower motor actually flows THROUGH the evaporator..so if frost formed on the coils, air can not get thru.

Any way to test to see if it is the evaporator causing my problem..I mean I can have a shop check pressures etc but what would I be looking for to determine if it needs to be replaced?

 

Reading the FSM, the compressor itself may be faulty or the wrong one was used.

http://www.nicoclub.com/FSM/Maxima/1997/HA.pdf

 

Can you point me to the page you saw that on? I skimmed thru it but didn't find where you are referring to.

 

On HA-11, it talks about the compressor having a variable displacement to prevent freezing.

Also, did they also change the drier? Usually compressor warranty states that it also requires proof of also purchasing a drier to honor that warranty.

 

They did not change the drier. Is there a way for them to test the compressor? It's going in Thursday for them to check it. I just ran the AC today for 10 minutes and the Low Side lines had already frozen.

 

I don't know your exact problem, best to let your ac guy figure it out. Air does pass through the evaporator. If its frosted over you'll get less airflow. The condensation that usually forms on it will drip out the drain. Its getting too cold and freezes over in your case.

 

Yeah, it's going in Thursday. I noticed some moisture on the plastic covering the Evaporator after I ran it the other day, but no drips onto the floor board. The drain tube at the firewall also had moisture in it so I know thats not plugged.

I have googled this like a ***** and think I have a over/under charge, or bad expansion valve...also, guess they should have done the drier too so i'll end up doing that as well if they have to evac the system again. Looks like the most expensive thing will be the evac.

 

if you just had the work done, it should be warranted.

 

It was just done the other day along with my Valve Cover Gaskets and Upper Oil pan Seals. The compressor, I supplied myself and they installed it. It's going back to the same place so I think they will make good on it...unless it needs another part i may have to pay something. Considering I just gave them $1000 for the job, I HOPE they make good.

 

It would be fair if you needed other parts to have you pay, but you should NOT have to re-pay the labor involved...or the re-evac imo

 

My thought too...Although even if I have to pay for the Evac, it's only $70 and I can install parts myself.

 

So just came back from the mechanic and we didn't really dive into it today but set up an appt for monday. He did say that it doesn't sound like the compressor is cycling OFF. Is there a sensor somewhere for the compressor On/Off cycle?

 

I assume since it is an SE that you have the automatic AC. There is a diagnostic program you can run on the unit that does some self-checking. Instructions are in the HA section of the FSM. Good luck.

 

SE does not necessarily have the auto climate control. Auto climate came standard on GLE...optional on SE.

 

Yes, there is a pressure switch on the dryer. Its below the drivers headlight.

I don't think our compressor cycles on and off though. At least I've never noticed mine doing that.

 

Thanks Jon...I knew about the pressure switch on top of the drier, but I have no idea what it does I'll let them know about the cycling...If you've never HEARD it, that would explain why he didn't HEAR it cycle...maybe it does cycle but we just don't hear it

EDIT: And I have the Manual CC

 

Also, let's say the evaporator is freezing, what would cause that? I ran it today and when the air stopped coming out of the vents, I turned the AC off and ran it on VENT mode for like 2 minutes, then turned the AC back on and it was blowing strong again. There was also about 1/8 - 1/4 inch of frost on that low pressure line.

 

Well when you say its not cycling off, do you mean it does not shut off with the climate control buttons? Or do you mean while the engine is running, a/c ON full blast?

My Fronty's compressor does cycle on and off while the engine is running. I assumed it was some new thing to help is fuel efficiency. Not sure but it works great so I'm not screwing with it.

You probably have a bad expansion valve.

 

It DOES shut off with the climate control buttons, but when it is running AC on full, I do not hear the compressor cycle...but I am not sure if it's supposed to or not. You know, like a house AC where you can hear the compressor cycle on and off to maintain a temp...the Max does NOT do that, again though, not sure if it should but you say you've never heard your Max cycle so

The expansion valve is right on the evap core...yes? I've been leaning toward the expansion valve being bad.

 

i don't hear mine either. just recharged the other day and not sure if its supposed to cycle. both cooling fans work and i see water dripping from the bottom

 

So, they say my drier is plugged up. They claim 2.5 hours to replace the drier NOT including the evac and refill time. Is it really that involved to change the drier?

 

Only if they have a team of one arm midgets doing the work.

 

That's what I thought. Is it just a couple of bolts on the drier to change it out? I have not really looked at it but I can't imagine it's too difficult.

 

I'm surprised the shop did not change the receiver/drier when replacing the compressor as that can void the warranty for the compressor. But as far as removing the receiver/drier there are 2 lines that go to it from the top and then one bolt around the bracket that needs to be loosened to pull the reciever/drier out. Also a hi/low pressure cutoff switch will need to be disconnected from the top. The bolt you need to loosen I believe is hard to get to so you may need to remove the battery and battery tray to get to it easily enough.

 

This isn't a DIY job, the system is full of R134 refrigerant. It needs to be recovered before the system is opened up. That will save you on the recharge because you will not be paying for refrigerant again.

If you open it up and let that refrigerant escape, the shop will get you for an evacuate and recharge once again and could void your warranty.

 

IMO it is a very easy DIY job. Have a shop evac if you want to do it the legal way. Replace the part. Then have a shop vacuum it down and fill it back up. Or just borrow the vacuum pump and gauges from autozone and do it yourself if you are a little mechanically inclined. As far as removing the drier it is only 3 bolts and a plug, maybe 30 minutes of labor worth if you have to take out the battery/tray. Definitely not 2.5 hours. GL!

 

I know I need to evac the system. It definitely sounds like a diy job after the evac which I dont have to pay for anyway. Thanks for the explanation metalgod3082. Their time MUST have included evac and refill time even though he said it didn't.

 

The only thing I have to add is, if you do it yourself replace the O-rings. I also like to replace the bolts with brand new ones, which is optional, but O-rings are a must.

 

O-Rings actually came with the Accumulator/Drier but I had some o-rings laying around anyway from the kit I bought for the compressor. So, yeah, I was gonna do that. Just gotta set up an appt for evac do the fix. Bolts...F-em, unless they snap on the way out, I'm not replacing them

Edit: I noticed on the new accumulator they have sealed the holes so moisture does not get in there...but how long can i leave that open before too much moisture wrecks the new Accumulator? I mean, obviously i need to unseal the holes to install but how long do i have, 1 minute, 15 minutes??

 

Well, replaced the drier today but the same lines are still getting g coated in frost/ice. Not sure if the ac will stop blowing out the vents cause I have not driven it long enough yet.

Expansion valve the next thing to check? I'll have to see if the shop will make good on this since they diagnosed it as the drier being the problem.

 

AC Air flow is still weakening after about 20 minutes of driving. However, if i puch the AC button to turn off the AC, after about 30 seconds, it will blow full power again for about another 20 minutes. Even after having the AC off for 30 seconds to a minute, it still blows ice cold air...just very weak until after that 30 second time frame. Any other suggestions? I don't feel like continuing to drop money into it. The only thing i can think of now is maybe the expansion valve....but to do that, i gotta evac the system AGAIN and put a new Accumulator/Drier in so I'm not sure if i'll do anything with it or just live with the quirk.

I also put some pipe foam on the AC Line (like the stuff you use for copper pipes in a house) and that seems to have stopped that line from getting frosted over.

 

I have been reading this thread and wondering how something like this can happen. To say the least, I am not an air conditioning expert. I consider myself lucky to be able to spell air conditioning correctly - and that's with a spell checker. But something popped into my head that my house a/c guy told me when I had to get a new compressor installed. I asked him to put in a bigger compressor for more cooling and he told me that he couldn't unless I also replaced the evaporator with a bigger unit.

If he put in a larger compressor, the original evaporator core would freeze over because the amount of refrigerant coming from the compressor would be too much, even though the pressure of the refrigerant was correct.

This sounds like what you have. The evaporator core is freezing up from the moisture it is taking out of the air blowing through it. This blocks the air flow. You turn off the a/c and leave the fan on and the air is still blowing cold because it is blowing over a block of ice - the frozen evaporator core.

Since you had the compressor replaced, could it be the wrong one? The 5th gen a/c compressors look the same as the 4th gen but are different. The ones used by Nissan are made by Calsonic, but I don't know how to identify which one is which.

 

Is this the same compressor that had the ding on the pulley?

 

Thanks Dennis, that actually makes sense. I wonder if they did send the wrong compressor. I have no idea how to tell, I know I ordered the right one with the right part number for a maxima with my production date.

I sent that one back and exchanged it for the one I have now.