A/C service valves

Earlier this year I bought a 1997 Toyota Tacoma. The guy I bought it from said the A/C system worked, however, it was a cold day when I looked at the truck so I didn't think to check if the compressor turned on. Fast forward to a warm day, I clicked the A/C on and nothing happened. I went to the auto parts store and got a recharge kit, squirted some juice in the system and the A/C ran cold for a few days before quitting again. I noted that at some point in time, A/C oil dye was put in the system. Great! I got a black light and found there was significant leakage at the high pressure service valve. In fact, when I took the dust cover off you could hear a tiny bit of gas escape.

Figuring this was the smoking gun, I replaced both service valve cores with parts off Amazon, borrowed a set of manifold gauges and a vacuum pump from a coworker and got to pulling a vacuum. After about 45 minutes of sucking, I let the system sit for another 30 minutes to see if I lost the vacuum. I was convinced the system was in fact sealed, so I went ahead and filled it up with 22oz of coolant. I replaced the old service valve caps with new caps with an o-ring inside that came with the new valves.

Fast forward a few days, the A/C stopped working again. I checked for dye all over with a blacklight but still, only found dye around the high pressure service valve. So, a couple questions -

-I'm guessing all service vales are not created equal, the the cheap ass amazon cores are garbage? Do I need an additional o-ring in there?

- Is there a chance the valve core seat is damaged somehow? I assume the o-ring would smush in there and take care of any imperfections.

- Is it safe to assume the service valve covers with o-rings would keep the gas inside a system with a leaky core?

- Is it possible the gas is leaking out elsewhere, but no dye is going with it?

- Any other thoughts or hints?

I really don't want to spend another $28 on R143a, only for it to all leak out in 5 days again. I also don't want to take it to a mechanic who will charge a premium for A/C service when I have all the tools here. This can't be that hard.

I should add, the valve cores I took out looked exactly like the parts I put in. I can't seem to find replacement cores on the Toyota parts page, only the suction hose/ lines with the cores already installed. Do I need to just replace the lines? They don't look that expensive on Rock Auto.

Thanks!

 

You did pull things apart and check the evaporator core as well correct ??

 

No, didn't look at the evaporator. I'm assuming the entire dash needs to come out to look? Also, if it were leaking, the system wouldn't hold a vacuum?

maybe I need to pull a vacuum, then wait several hours?

 

Yes give it a few hours under vac or pressurize system with compress air and listen to system plumbing with a mechanics stethoscope. 9 times out of 10 if the leak is not externally obvious then its the evaporator, especially if previous owner was a smoker. No the dash should not have to come out at least my 99 didn’t, i did this a few years back its not to bad, now the heater core, different story, dash comes out for that one, be nice to it.
R/
Andy

 

Yes, leaks should reveal by losing vaccum. If you have a source to borrow a sniffer that would let you check the evap case w/o disassembly if you recharged the system.

I had Dads old homemade vaccum pump. It would pull down to about 30 IIRC, and I'd let it sit at least 12 hours and see what happened. The advantage of DIY work at home with other wheels available.

 

Like other parts I don`t know if I would trust cores from Amazon for tires yes not AC.

It might be you just got a bad one. They were indeed for Ac to handle the High side pressure?

I would grab some from the nearest Supply house . You might need to replace the complete valve.

When I was doing HVAC work vacuums sat at least 8 hours or longer after being pulled.

Good luck !

 

okay, so I think I found the problem - I believe it leaks where the pipes go through the firewall. I took out the fan speed resistor which allows you to peak inside with a UV light. One of the pipes was covered in dye. So, I needed to take the entire evaporator box out of the dash. Not a huge job to remove surprisingly.


I also took out the fan box while I was in there. This thing was nasty and I wanted to clean it up a bit while I had the opportunity.


Here you can just make out where the dye was leaking from, under the rubber that goes over the pipe. There was a lot more, but I wiped it off thinking I would recharge the A/C one more time, then check to see if the dye came back. I decided to just replace parts because they are pretty cheap, well, most of them.


Evap core on my picnic table. This thing is nasty.


I ended up ordering a new evap core, expansion valve, pipe set, pressure switch, dryer, and the lines that go to the compressor. The lines come with new valves. I was surprised how inexpensive this stuff is, when you don't buy it from the dealer that is. Two parts came directly from Toyota; the pressure switch and the pipe set, which cost more than all the other parts combined. It's about to get real hot here in So. Cal and I don't want to be chasing leaks around all summer. Now I need to figure out how much PAG oil to put back into the system, put it all together, vacuum it out and recharge,

 

With a little searching you should find that imformation.

good luck!

You can clean your old evaporator core.

In that period of my life many were cleaned the product is called coil cleaner sold by many vendors.

 

Wish I'd seen this sooner; ran into a similar issue myself a couple years ago

Here's all you need as far as putting things together, PAG volumes, and recharging:

Climate Control – ADVENTURETACO

 

Thank You Sir for posting!

 

First off, @turbodb Thanks for the excellent write up. This kinda info is super helpful for people like me who like to wrench on their own stuff but have relatively no idea what they are doing because.... Not a mechanic. I spent the time cleaning all the parts of the AC system. This thing was gnar' so it felt good to clean everything. The squirrel cage fan blower looked like it had been running in a drywall factory for 20 years; just gunked with crud. Sadly, I couldn't get the plastic fan off the motor armature so it's not perfectly clean, but good enough for me.


But, before installing everything back in, I want to add some cables through the firewall for an amateur radio install. I carefully used a step drill and popped two holes through the firewall and added some gland grommets. With those in place I fed some wire; some 10 gauge speaker wire (for powa!) and some RG58 for the antenna feed line.


I then re-assembled the evaporator enclosure with all new parts, including the evaporator, expansion valve, pipe set, and pressure switch.


I'd like to say, that removing all this stuff and putting it back in was actually very easy. You only need a 10MM socket, a Phillips head screwdriver, and a bit of patience. I also installed a new line between the new evaporator and the expander, and installed a new dryer. very easy job. Oh, I should say I added 40cc of oil to the evaporator and another 20cc to the dryer output port as written by @turbodb. I also used new green o-rings everywhere and coated them with a light layer of pag oil. My only problem so far was the dryer bracket bolt was rusted, so I needed to drill it out and install a new nut and bolt in it's place. Easy.

Now, I have a new problem which I'm kinda stumped on and need some advice.. I felt like I should replace the rubber suction line between the compressor and the evaporator, as the crimp where the assembly changes from rigid aluminum to a rubber hose looked a little "wet", as to suggest that it leaks a little bit. I never saw any UV dye in this location, but perhaps you can't see it on a black hose. Parts are cheap, so I ordered a replacement along with everything else from Rock Auto. So, I removed the old hose and put it aside without much thought, and went to install the new one. Turns out the replacement hose is much longer than the original! Figuring I ordered the wrong part, I went to double check my numbers, but they were correct. hmmm.... I decided to order another hose from Auto Zone. They have free delivery and I can return the unused part to my local store if needed. When the second hose showed up, it's also the same length. grrrr! I guess this is why you want to buy genuine parts from Toyota. Lesson learned.

Okay, so my question, is it okay to have a long ass hose in there? It seems like the dip in the hose would be a place for oil to collect. Additionally, I'm kinda worried about it being so close to the exhaust manifold. Also, the rubber is pretty ridged and it doesn't seem to bend well. I feel like this would put stress on the union joint back to the evaporator and perhaps cause a premature failure somewhere.

Thoughts? It's going to be hot starting this weekend, I need A/C. Do I order the correct hose from Toyota or run a generic long hose?

 

Okay, so I figured out the hose length issue. Problem was, I wasn't paying attention. See below. The first photo is the old suction hose next to the new one. Wrong length and shape, right?


Nope, not so fast. looking closer, the fittings which mate to the compressor are reversed. This must mean the hose routes differently than the old hose. I have an early Tacoma, a 97, so perhaps this was changed in later production models.

The old hose came straight off the back of the compressor, where the new one exits to the front, then loops around and connects to the evaporator. I tried to take a photo but it's hard to capture.


I'll be pulling a vacuum and recharging the system later today or this weekend. Hopefully I won't need to monkey with the A/C system in this truck for years to come. It's got other issues that need addressing, like the suspension. It's totally shot. It feels like a boat driving down the road. The other weekend I put about 40 2x4s in the back to haul out to my cabin and I swear the rear leafs were arched backwards. One step at a time.

 

Okay, just to update y'all on my A/C project. After getting everything installed and found some free moments, it was time to pull a vacuum on my system. Fingers crossed, here, I was feeling a bit nervous like I missed something or there might be another problem lurking around the corner. I hooked up my co-workers manifold and vacuum pump and began to suck. I let it run for about 5 minutes before shutting it down for another 5 to see if the initial vacuum was holding. With no loss (or, gain I should say) in pressure I let 'er rip for another hour. After the hour was over I let it sit for 3 additional hours under vacuum to really make sure it's going to hold. Since I'm doing this on the street in front of my house, I needed to hang out with the truck, as it can get quite busy sometimes.

The previous owner had a dog, evident by the fur in places a vacuum cleaner could never reach. I took this time to remove both seats and really get in there to clean things out. This was successful as the debris canister on my Dyson was 1/2 full of someone else's dog. Since the seats were out and I wasn't doing anything except drinking beer and watching an A/C gauge that wasn't moving, I took the time to run more cables for my amateur radio. Power poles were soldered onto the wire I previously ran through the firewall, and I terminated the coax to my temporary NM0 mount. With the connections in place, I ran everything under the passenger door trim, made a small incision in the carpet and fished the coax, power and a cat 6 cable through.

I zip-tied the radio to the bottom of the passenger seat, bolted it all together and connected the wires. At this point I was getting good and tipsy so what better time to charge the system up with R134a? It's now or never! Using a cheap-o laser thermometer, I made a base measurement of the ambient temperature.

Then I added the first can of cold juice. It went in easily without a problem and the compressor kicked in. With the second can about to go in, something happened with the can valve, and I lost a bit of gas. Because of this I emptied the whole can into the system, this one took a bit longer. Rechecking the temperature, it's now blowing 49 degrees.

After a few days of not driving it, it was time for a road test, and I was worried everything leaked out and all the work and expense I went through wasn't worth it. This wasn't the case. It was still cold! It was actually colder than before; I measured 42 degrees. Wooohooo! It's now officially painfully cold and I'm confident it's not leaking anymore. Hopefully this stays true for years to come.

So, I want to thank y'all for the encouragement and for reading my long winded blog post on my journey through A/C repair. I'm hoping the writeup and photos help others who are also having A/C problems. Working on the system isn't terribly hard at all.

Next, I need to tackle my suspension, which feels completely shot; the truck rides like a boat - in a bad way. My eyes are now bleeding from partially reading the thread "OME setups on 1st Gen Tacomas". Don't know what I want to do yet, but something needs to be done.....

 

I noticed the Morse code Keyer. So are you an icom or yeasu kind of guy... or a Kenwood perhaps?

 

No compressed air it's full of moisture, waste a can of Freon.