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instructions on how to replace the AC expansion valve and/or evaporator

311K views 49 replies 24 participants last post by  Nod269er  
#1 · (Edited by Moderator)
i finally got through this job last night so i tool photos as i put it back together as a how-to since i couldnt find decent instructions or photos, i wanted to at least offer some insight in how to accomplish replacing the expansion valve or evaporator.

the impetus for me was a leak in the AC system o-rings at the condenser so i decided to replace the expansion valve while the system was empty and since they seem to be a weak point.

okay, lets see if my memory serves.

first step is disconnect the battery.

then remove the black cover under the passenger side of the dash. it pulls down from the front and is held in by clips that snap out. it can then be pulled forward to be removed. then the trim under the glove box is removed. i believe there are 2 black screws and the rest is just snapped in place.

the glove box door can now be removed by taking out the 3 nuts at the bottom.

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now remove the glove box liner. there are three screw circled at the top, but there is also one or two screws at the bottom (not circled) that need to be removed.

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also pop out the connection for the airbag by prying up the front edge then it should pop out. slip it though the hole as you remove the liner and disconnect the light.

remove the plastic floor vent duct on the left. it just pulls off and the plastic clips will release.

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there is some velcro on the bottom of this duct to help hold the carpet in place.

next disconnect the 3 wire connections at the bottom of the blower assembly, then remove the white bracket.

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remove the vent for the passenger side vent. the center section unsnaps and slides to the left, then can be rotated down and pulled off. the vent remaining on the left can also be pulled off.

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next the airbag needs to be removed to access a bolt for the blower unit. it doesnt HAVE to be removed, but it would be quite difficult to access this bolt. to remove the airbag there are 6 bolts holding it in place. first disconnect the wiring by rotating the white plastic retaining bracket down the press the release button and pull apart.

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once these six bolts are removed, there are two clips in the top that will release when the airbag is pulled forward, or better yet, pushed from the backside out.

now it's time to tackle the blower assembly. it helps to remove the weight of the blower motor. disconnect the wire running to it and remove the 3 screws holding it in place. here is a view from the bottom showing the wire connection and the screw locations.

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the blower motor will then drop out. now remove the case/housing it's located in. here are two reference photos of what this looks like removed.

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there is one nut the three bolts holding this in place. the nut is on the firewall, one bolt is near that directly above a cooling line

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another bolt is by the cover for the evaporator

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and the last bolt is the difficult one to reach behind the airbag

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now disconnect the blue wire/cord on the right side. the end slides off the lever and then pull the cord out from the clip.

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even though everything is now disconnected, it needs to be pulled down. everything around it including old foam seals help to suspend the housing in place. there is also a white plastic wire clip on the top that can be popped off.

once that is removed, pull down the carpet and now there is clear access to the evaporator cover. here is a photo of it removed to show the bolt locations.

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do take note that one bolt is also holding a probe in place that will certainly need to be re-inserted later.

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assuming the AC system has already been purged, disconnect the cooling lines under the hood going through the firewall.

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i broke them loose form above, but had better access to unscrew and remove them from underneath.

form inside, pull the cooling line connection out from the firewall slightly and slide them and the evaporator out.

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you now have removed the evaporator and expansion valve. you can separate these by taking out the two allen bolts.

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installation is pretty much the reverse.


so, i hope i didnt skip any steps but this should give a better understanding on what is involved with removing and replacing the evaporator and/or expansion valve.
 
#3 ·
had the system vacuumed and filled. works perfect and blows at about 43 degrees... but there is a leak. apparently the front line that runs from the dryer to the evaporator under the radiator, rust weakened and made the tube brittle where is clamps and it fractured at some point when i was working on it.
 
#6 ·
^ yah, the line that runs under the front subframe very commonly fails on our cars due to rust - seems to mainly be because of the the two steel clamps that hold it to the frame though, since the line itself is aluminum

and added to sticky- great job and great help!
 
#7 ·
is this a dealer only part? local stores dont have it, nor rockauto. im a little leery to spend the time sifting through local salvage yards thinking they will be rusty too. well, i do have to go there next week to fix a friend's car, so maybe i will give it a whirl.
 
#8 ·
yeah, it's pretty much a dealer part only.

personally though, I had good luck finding one at the junkyard that was in good shape, and so has a number of other gen3 owners, so def worth a try!
 
#9 ·
Great instructions and illustrations!

One point I want to be clear about is, is it necessary to remove the airbag if all I want to do is access the blower assembly?

The blower makes a rattling noise that sounds like the bearings are shot or something has gotten inside and is contacting the fan blades. It also smells like a dead rodent is in there.

Your instructions indicated the only reason to remove the airbag was to be able to remove a screw/bolt that you had to remove after removing the blower housing.
 
#10 ·
no, you dont have to remove the airbag to remove the blower motor. the airbag only blocks the blower motor housing if you want to remove the complete assembly. the motor itself can be accessed from the bottom and can be easily removed.
 
#12 ·
Great write up!! I am just finishing my expansion valve replacement now. The one thing I would add is that you can remove the evaporator core/expansion valve assembly entirely from inside the car (internally there are 10 mm bolts connected to the aluminum coupler that sits in the firewall. Remove these bolts to pull the "cooling lines" away from the firewall and remove the evaporator assembly). No need to mess around with the fittings on the engine side of the fire wall. This would have saved me lots of time and frustration to figure out before hand.

Again, awesome job with this writeup... it's a huge help!
 
#13 ·
can you post a photo (or use one from above) to show which 10mm bolts you are referring to? it's been a number of months since i did this and i'm not quite clear on the bolts you are referring to. i will amend the instructions to reflect this. thanks for additional info!
 
#15 ·
That's a pretty good video !.

I found another item to clean Evap.......Toy#00289-ACRKT...About $20.00 at dealer.

It's a Power Foam Evap Cleaner Kit.....Just plug into evap drain tube and shoot her in !,

then repeat a couple times....it'll drain out and then just put in refresher that comes with the kit....:)

j
 
#17 · (Edited)
hmm, Ghettosled.

The Factory manual says:
EVAPORATOR REMOVAL
1. DISCHARGE REFRIGERANT FROM REFRIGERA–
TION SYSTEM

2. REMOVE BLOWER UNIT

3. REMOVE EVAPORATOR COVER
(a) Remove 2 bolts for the liquid and suction tube.
(b) Remove 8 screws and evaporator cover.
(b) Remove 2 bolts using a hexagon wrench and separate
the evaporator and expansion valve.

4. REMOVE EVAPORATOR
(a) Pull and remove the evaporator.


I have the classic signs of a sticking expansion valve. I am getting a normal low and high side pressure readings when starting up the car. The a/c is ice cold and then slowly gets warmer and warmer until no cold air while drving the car for 20-30 min. After driving back home, I checked the pressures again. This time, the low side is vacuum -30 psi and the high side is up.


I ordered a Denso expansion valve from sparkplugs.com...densoaftermarket.com linked me to their site. (costs about $40 with shipping) I am debating about adding a a receiver drier which is just $15 more but it is on back order. If I cap the ends of the a/c then I probably won't get moisture in the system and can get away from adding a drier.

Another thing is got a free (with deposit) loaner set of manifold gauges and and a high quality vacuum pump from my local Autozone.
I found Johnsen's brand refrigerant on sale at my local Big Lots store in Florida for $8 / 12 ounce can ! I will need to get a couple of o rings for the evaporator at my local Toyota dealer.

I saw an a/c solvent cleaner to clean out a/c parts at Autozone for $16 , but it is generally recommended not to use it to clean the expansion valve. The Toyota factory manual just recommends to blow out any debris with compressed air in there. If it is mechanically stuck, then it probably is better to go ahead and put in a new one instead of doing the same job twice.

So, I think anybody can do this job for under $100 with the right tools.
 
#19 · (Edited)
as to dead rodents, our first Yellowstone trip in the Camry Wagon saw 3 chipmunks take up residence in our car, under my daughters car seat (cheerios!) and one by one jump into the blower... Had it serviced in Denver and the guy buttoned it up and called us to come get it then 10min after said he'd "found the third" I covered the floor ducts with SS mesh when I got home.

and its only 48 in/lbs = 4 ft /lbs !
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#50 ·
Bustedstuff104,

The service manual says 48 INCH-pounds, not 48 FOOT pounds like Tedmich is writing !!!

You want it screw driver tight, not tightening something with a cheater bar !

You can judge how tight it should be when you untighten it with an allen wrench.

smr
They call it "German tight" as you tighten it by gauging it with your elbow as it pivots. My wife's 2004 Toyota Sienna I was fixing her a/c but found the second hex bolt seized I ended up cutting the expansion valve, but then it wouldn't budge! After 3 days I was forced to access the hood part as I was in a hurry while it is still hot in SoCal. Dang, The hose locks were tough it took me 2 hours just to remove and I am a seasoned DIYer! I finally separated the hoses(firewall) but only the low pressure hose gave way; the high pressure was resistant I couldn't pull it in under the passenger dashboard. For some stupid reasons I did not completely cut the expansion valve thinking it would easily bend but they sure are sturdy! I would have to finish it off tomorrow since I am already pissed. Doing DIY A/C flush, removal and installation is the proverbial PITA. What could be done in one day under ideal conditions could take you days if the minivan you are working has seized parts you want to kick it. Yeah it can be done, that is, removing the expansion valve without going under the hood and without even removing the blower motor assembly but it has qualifying conditions like bolts are not rusted and seized and it makes your work faster. And since my experience involved a 2nd Gen Sienna whose evaporator was enclosed, and I will probably be forced to remove the dashboard to access it by removing the screws in the middle of the housing, and I am not willing to do that anymore as I am cash strapped due to this pandemic, every documentation you show here should be vehicle specific as these models may be similar but not the same. Just my 2 cents on that, should you decide to do it yourself. It can be done. But you have to have the extra patience when there's a bump in your quest, and trust me it could be a domino effect, as you think you solved your issue, but by the time you finish you noticed something brewing on the other parts that will call you back soon.
 
#21 · (Edited)
Yes the 48 ft-lbs did seem a bit excessive now that you mention it :facepalm:
I was trying to fix a leak after I put back on my evaporator after replacing the expansion valve. So the problem was either damaged fins from trying to force out the evaporator before it was totally seperated from the firewall or the allen key bolts not being tight enough. Anyway, evaporators are only $15 at the yard around here so no big loss, except for pride lol. The expansion valve comes as part of the evaporator when you pull it from the yard, so I'm thinking of replacing both together so I don't have to worry about o-rings, etc.

By the way, as a previous poster mentioned, you DO NOT have to remove the a/c lines from the firewall on the engine-side. There are 10 mm bolts that attach the a/c lines to a 1.5 inch thick aluminum disk from inside the cabin and from the engine bay. All you have to do is cut through the 2nd layer of foam that hides the two bolts and you can save yourself some greasemonkeying.
 
#22 · (Edited)
A "heads up", so everyone knows what lies ahead if you eventually move up to the newer model Toyota's, take a look sometime at how to change the evaporator in a 5th Gen. Camry.

You have to take out almost everything from the interior firewall. From the all of the upper and lower dash, instrument panel, to the A pillar trim, center console, even front door weatherstripping... I mean that just gets you to first base. It is a time bomb and shockingly unreal :wtf:

An evaporator (or heater core) leak in most of the next generation Toyota (not just the Camry) will basically mean the end of their life, or the driver will elect to just drive as long as they can endure without heat or A/C.
 
#24 ·
Ghettosled - Thanks for taking the time for thorough instructions with photos. Hayne's repair manuals don't cover this at all. My son's 94 Camry V6 expansion valve failed and I knew it wasn't going to be fast or easy job but I tackle it yesterday. Although time consuming (~6hrs w/breaks). The air bag was the toughest to remove as I could not see the top right bolt but with the picture I knew it was there. I was forturnate as when I brought a 99 camry that as a insurance total for the engine for my another son's 98 camry I stripped it of other useful components and the HVAC box was something I kept which had the same expansion value. I did replace the O-rings and added the oil before I charge it. Now we'll see if it hold up.

Again Thanks it made a tough job much easier.
 
#26 ·
Thanks Ghettosled. I just pulled my evap coil out. It's not necessary to mess with the air bag. If you look carefully, you can see and reach that bolt at the top. Caution to anyone doing this for the first time....when all the bolts are out and you're ready to pull out the blower housing, make sure to pull it out to the right a little bit before pulling it down and out. I just pulled mine down and broke a plastic pin that is up near the top left. It holds it in place, instead of using a bolt. I had to super glue it back on. Also, the videos by Scotty Kilmer are great, but in this video he skips A LOT of steps. It's not nearly as fast and easy as he makes it look. Of course, if you watch the video of the newer Toyota expansion valve replacement that Tedmich posted, you'll then be glad that you have an older Camry. Watch that video and you will see how INSANE it is. Toyota engineers should have made it easier to access. Perhaps designed to force you to buy a new car once it gets to that point. Absolutely complicated procedure just to replace the expansion valve, wow, glad I'm not doing that.