kiyakerz

iTrader: (7)

I'm in the process of trying to replace my expansion valve but I'm having a hard time getting to it. I've taken off the glove box, pulled the blower motor and I'm working to get the rest of that plastic housing off. I've removed all visible screws that I can see, and even like 4 or so screws from behind the housing. The bottom half has started to separate a bit but it seems to be attached to something in the rear and I have no clue what's holding it in place. I've looked at all data and the fsm and all I can tell by their instructions and diagrams is that I have to separate the bottom half... not much else in there.

Any tips/help would be appreciated

Amave

if it is anything like an Altima, you have to evacuate the system and detach it at the firewall on the engine side.

then you remove the evaporator and case at the same time then you can replace the expansion valve

kiyakerz

iTrader: (7)

I've discharged the system, and disconnected the firewall side. I'm having a hard time removing the evaporator casing.

kiyakerz

iTrader: (7)

Well I finally figured it out, seems I didn't have to do anything on the interior (DOH!). I just had to disconnect the high and low pressure hoses from the firewall, then the expansion valve was right there being held in by two hex screws. Not sure why I couldn't find this in alldata or the fsm, so hopefully my post will prove useful for someone else in the future.

KBCobra

Bringing old thread back. Does anyone have pictures of where the expansion valve is? The mechanic wanted to charge me $250 to replace mine so I figured I'd learn something new and buy the expansion valve (~$30) and do the work myself. Thanks in advanced!

kiyakerz

iTrader: (7)

Hey man, I don't have my maxima anymore or I'd take some pictures for you. However it's really easy to find. Just follow the A/C lines to the passenger side where they go into the firewall (The part of the car that separates the cabin from the engine bay). The a/c lines there are attached directly to the expansion valve. There are just a few screws if I remember correctly that need to be undone in order for you to easily remove it.

KBCobra

Hey, thanks for the reply. I have followed the lines but I don't see anything that resembles the pictures of the expansion valves that I have seen. I did however, find this. It is held by two hex screws, as you previously stated and it does appear that there are AC lines running into this (i think I'm not too positive if they're AC lines).

kiyakerz

iTrader: (7)

I believe that big hose with the insulation is your high pressure power steering hose. The a/c lines will be behind that along the metal wall. You should be able to follow them from the driver side along the wall to the passenger side. The a/c lines will definitely be smaller than the high pressure power steering hose.

KBCobra

I see the high and low lines going into the firewall. Do I need to unplug them in order to get to the expansion valve? I figured I didn't have to unplug them yet to get to the expansion valve since you said no work had to be done in the cabin of the car. I took off my glove box and everything but I didn't see anything inside. I couldn't get the box apart but I did see the small condenser inside the box. I had all kinds of leafs in there and dirt I still need to evac the system but I am just looking for info so I can order the actual expansion valve.

kiyakerz

iTrader: (7)

It's hard to see since it is inside the firewall but you will be doing this from the engine bay and not from inside your cabin. The expansion valve is a little metal block probably 2in by 3in that the a/c lines plug into. There is a hole in the firewall that the block is resting in. You will definitely need to evacuate the system first. After system has been evacuated you can disconnect the a/c lines from the expansion valve. I believe you will need a hex screw driver to remove two screws holding the expansion valve into place. Hope this helps and don't give up man it's definitely worth doing on your own. Lemme know how you make out.

KBCobra

Is this what you're talking about? Am I supposed to pull this out? By the way, How did you evac your system completely? Did you take it to a shop or did you do it yourself?

kiyakerz

iTrader: (7)

That's the one! There should be something you can undo like a a screw to a plate or something holding both lines in place, once you get that plate off you just pull each line out (should be a little friction since they have o-rings on them). When installing the new expansion valve make sure you put new o-rings on (they usually come with the new expansion valve).

As for evacuating the system there are several ways to do it. I took mine to a local shop and had them evacuate it for me. I believe you can also buy a cheap pump from autozone to get the job done as well. I've even seen some people just loosen the cap and let all the freon blow out but that is illegal and also bad for the environment. I would try to work out a deal for an evacuation and recharge with a shop so that you can bring it back to them after you complete the work on your vehicle.

KBCobra

I'm trying to pull it out of the firewall but I can't. I can only get it to go out so much lol do you remember removing the screw in between both lines when you did it in order for it to come out?

kiyakerz

iTrader: (7)

Yes remove that screw first, that is the only thing holding the lines in place.

KBCobra

Alright, Thanks. I was out there for about 30 minutes trying to find the right size for the screw but I had no luck lol fail. I will try again later. Is there anything else you changed? What gave you the impression that it was your expansion valve failing, not something else?

kiyakerz

iTrader: (7)

I actually don't think mine was bad, I was just replacing it since I had already done the drier and compressor. In your case I can see freon leaking from your expansion valve so I would assume that either the expansion valve is bad or the o-rings are bad. Either way replacing it will fix both problems since a new one comes with new o-rings.

KBCobra

Oh, okay. I didn't even see that until you pointed it out lol my AC doesn't blow any cold air at all and I already recharged it. I will order it this weekend and I'll slap it on. I hope that fixes the problem. Southern Cali requires you to have AC lol the DMV should demand it. Thanks for all the help. I'll come back with the results as soon as everything gets done.

I just received my Expansion Valve in the mail and when I was working on getting it put on, I noticed it was a bit different shape than OEM. Question: Was it the same for you or was it the exact same shape? I ordered mine from 4Seasons (4s.com) So much for being excited to get my AC fixed over the weekend

No further questions. I was able to install it this morning but it was a huge hassle because of the tiny screw holding in the plate like cover. I dropped so many screw drivers into the engine trying to get it out but I managed. Hopefully that fixes my problem, now to wait to get it recharged to see the final verdict. keeping my fingers crossed.

DarrellGibson

I really wish KBCobra would have posted his results. I'm having issues with my I30 and I can't tell if it's the compressor or the expansion valve stuck open. I don't really want to drop $500 on a compressor/dryer/expansion valve if not necessary.

My AC was working excellent but only intermittently. It would blow freezing cold then no cold at all then freezing cold again. I've verified that the compressor clutch is engaging but I can tell there isn't much of a load on my compressor at all now that it has stopped cooling completely. My lines are both just warm, neither hot nor cold. I've had the gauges on the car and it shows about 65psi on the low side and 100psi on the high. That's at idle or at 2000 rpm (actually the low pressure dropped from 70-75 to 65 when reved to 2000rpm, then stayed there even at idle) . Ambient temp was 80°.

Does anyone know if there's a way to for sure diagnose/test an expansion valve? Even if I have to remove it to diagnose/test it thats OK. Obviously I'd rather know before I lose my freon of its bad or not but if I have to lose it I will. Any advice or suggestions are greatly appreciated. I will post results as I go along for ones who have this issue in the future.

DarrellGibson

Well I promised to follow up with what happened in my last post...

THanks to another member, I found the factory service manual (FSM). According to repair steps spec'd by Nissan, when I have pressures like the ones I reported earlier, it's time to replace the compressor. Most AC mechanics will tell you that any time you open the system you need to change the dryer. So since I suspected the Temperature Expansion Valve (TXV), I would have to replace it, the dryer and use two cans of freon just to test and see if it was the valve stuck open. The total cost for that would be about $100. Since everything was also pointing to a shot compressor, I just went ahead and bit the bullet and bought the compressor, TXV and the dryer. They were running a special at AutoZone when you get $35 off when you buy those three items. I wasn't too fond of AutoZone's compressor though as it only had a 90 day warranty. O'Reilly, had a compressor for about 25% more money but with a two year warranty. When I was pricing it out on the phone with O'Reilly, the manager added 'and don't forget we price match!'. So I took my quote from AutoZone in the next day when my parts came in and he matched their price! Technically they didn't have to since the compressor wasn't apples to apples. AutoZone does sell a higher priced compressor (that cross reference with the O'Reilly one for the same price.) So I was pretty excited to get out the door with all three parts for $372.

Now for the installation feedback. I have never done an Air Conditioner before, nor am I a mechanic. But I do know how to read and follow directions. I spent several days reading and rereading the FSM as well as watching YouTube videos from everything about removing the evaporator to how to pull a vacuum and how to charge with Freon. I have to say I was very astonished at how easy it was. Because there are already many videos showing how to get parts out, and the pictures and specs in the FSM, I really didn't struggle very bad at all. I can't even begin to imagine how hard it would have been to remove the evaporator of I didn't know where the bolts were that held it on and that it could for a fact be squeezed through the little area under the dash by only removing the glove box. That was the hardest part, but it was worth it. The guy above who struggled with the little Philips screw that held the plate like cover on the TXV was not alone. On my 2000 Infiniti I30, the screen head stripped completely out. So it was easier to just remove the entire blower/evaporator unit and I could work on that sure outside of the car. I ended up having to drill the screw and use and easy out to remove it. I found a screw with the same size threads in my misc screw jar and had to grind the head down a bit so it would fit in the recessed hole in the plate, but it worked fine. I also really wanted to remove the evaporator since I had seen so many pics on the net of nasty clogged up evaporators. Mine was no exception. I used Brake Cleaner (non-chlorinated) to get the greasy junk off, then a nylon brush. Once it was clean it still stunk (like old lady, my wife says), so I got some Scrub Free bathroom cleaner with bleach that works on mildew and I soaked it several times. Once I finished it shined like new and smelled good too. If you are working on your AC, I recommend this step since the Infiniti/Maxima of this vintage doesn't have a cabin filter to keep junk from getting in and caking it up. It is possible to do some cleaning without taking the evaporator out of the car. There is a narrow door that is about am inch or so wide and as tall as the box that comes out right after removing the glove box. You can then see the evaporator. I have heard they make a chemical you can spray on it to clean it without removing it, I'd Google or ask at the parts store of that is your task at hand. Don't worry about where the liquid will go, because the evaporator box is designed to leak out of your car. There is a drain, you probably can't see from that little door, but it drains right out onto the ground. If the drain is clogged try a little bit of compressed air to blow it out. Be very gentle with the fins on the evaporator, they are very delicate and by only slightly bumping them or hitting with too much air pressure they can be bent and reduce your cooling.

Since I had the system apart this way it was also very easy to flush everything in the system. I did not have to remove from the car the high pressure line that runs between the condenser and the evaporator. That would have been a real pain to remove. But since the evaporator was out of the car, I shot the flush and then the air onto the line from inside the car and it just fell out into a bucket under the condenser side of the high pressure line that I had already disconnected from the dryer. The only other two lines that are in the system both connect to the compressor. The low pressure line was already disconnected from the evaporator and so I also disconnected the high pressure line from the condenser and removed the compressor with both of the lines still connected to the compressor. This I found was much easier than then YouTube video i saw of a guy removing his compressor and removing the lines from the compressor while it was still mounted to the car.

I flushed both lines and the connected them back to the compressor and had someone help me pull them up through the engine compartment as I lifted the new compressor to its mounts.

Incidentally, I also flushed the evaporator while I had it out.

I don't own a flush gun, but for $50 AutoZone will let you borrow one and they give you the money back when you return it. Unless you don't care about your air working after you do your repairs, I would highly recommend you flush every line and the evaporator. Many guys now say you can't flush modern Condensers since the capillaries are so tiny. So I didn't even try. If there is junk in the condenser, it should get caught by the dryer. If you get a restriction in the dryer that should be pretty easy to diagnose with gauages and a fairly easy fix.

I would say my total time for labor of removing all of the components and cleaning and flushing was around 5-6 hours. And some of that time was spent going back to the smart phone and rereading the FSM or Goodland for a specific issue I was facing.

Then the next day I reassembled it all in about 3-4 hours. Once it was all back together I pressured it up to 100psi with Dry Nitrogen, which does two things for you, one it let's you know if you have a leak, and two it helps Remove any moisture that may have been trapped in the system. While I had mine apart I replaced all of the o rings on every fitting. O'reilly, didn't give me o rings with the compressor (arrg) and they also didn't have any part number for rings. Fortunately AutoZone sells a pack of rings with enough to put a ring on every fitting in the car. It's a bit pricy at $13, but for all of the trouble I went though it was excellent insurance. The FSM has a page with a diagram that shows the size of every ring at every fitting if you just want to get individual rings or if you aren't sure which one to use. The effort of changing the Rings paid off. After I put the 100psi of nitrogen into the system, took a picture of my gauages, then sat down and drank a craft beer. I took about a half an hour and when I came back my gauges hadn't moved even a hair. So I evacuated the system with a pump that AutoZone loans out ($155 deposit) For about 50 minutes or so, then I charged with the prescribed two 12oz cans of R134a.

When done my high side pressure was just a little high for what the FSM specs, (about 200-225), but the low side was right on and the inside air at the vents was on the bottom side of the FSM specified range of 49°.

I don't know for sure what made my old system fail, but I suspect, it started to leak. Someone had entered dye into the system to try and find the leak. I suspect that they probably over charged it and that burnt up the valves in the compressor.

Im super happy with the outcome and I know that I could not have paid anyone no matter how talented or experienced they are to do as good of a job as I did. It's my car and I care more about it than any hired tech. I've learned something I always wanted to and saved a bundle of money. This is a technical job and it does involve a lot of reading to make sure you don't mess something up, but if you can read and follow directions, you can do it.