2004 Toyota matrix XR 1ZZFE 191,000 miles
First symptom I noticed was the air conditioner stopped blowing cold when I’m sitting at a stoplight or idling in traffic for a long time. I figured it was just low on refrigerant, considering the age.
I got some gauges And a vent thermometer And looked up Temperature related charts online. 75°F the low side should be from 35 to 45 psi, and the high side from 150 to 170 psi.
The low side read about 20-25 and the high side just a little over 100-120 with the AC on full blast and the engine up to around 2000 RPMs
So I added a little refrigerant. No sealer or oil included. I got the low side up to 30 to 35 psi. The high side by then was reading about 175
I stopped there. The air temp in my vents Dropped maybe 5°. Real close to 40.
So I ran it a while and put the gauge back on just to check it. Low side was about 35 psi, but the high side was getting just a little past 200, way more pressure then it’s supposed to have at the ambient temperature of 75°. Also, after letting the car idle a while with the air on, I had the same problem of the AC not working after idling a while.
I guess I’ll have to take it to a shop, but can anyone diagnose my problem by this description?
I will also mention the humidity is pretty high
my cooling fans Seem to be working, and I Sprayed The bugs and debris out of my cooling fins
I'm not an "A/C guy" but I live in FL so I'm forced to "dabble".
Before the 1st start of the day, hook up your gauges. With R134a they should read (almost) equally (car not running) and should be the same as the temperature outside.
I was working on one today in the 95 degree FL heat. (Engine off, car was sitting for a few hours) both gauges read just about 95.
So if you have an older system with an orifice or a newer one with an expansion valve, that tells you there isn't an obstruction in the system. (because the pressure is able to equalize).
So in my case today, I started the car and turned on the A/C. The compressor clutch engaged and the A/C blew nice and cold.
But then, the pressures on the high and low side started climbing past spec.
I looked at the condenser coil and it wasn't dirty but I noticed the fans weren't running so I shut it down.
The A/C system is different from the Engine System. The engine wants to maintain a certain temperature and cycles the radiator fan On and Off to maintain that temperature.
The A/C system can't work without air blowing through the condenser coil.
It will work fine at cold start. (the condenser is cooler than the hot, high pressure, high temperature gas coming out of the compressor, and the gas cools in the condenser and turns to a liquid) .
But that doesn't last long. The condenser heats up really quick from the high pressure, high temperature gas.
It will work fine while you're driving and air is moving through the condenser, but if you get caught at a long traffic light, without the cooling fan working (full time) that high pressure, high temperature gas can't be "condensed" into a liquid.
So it can't be converted from a high pressure, high temperature liquid into a low pressure liquid when it passes through the expansion valve and "boil" when it's released into your evaporator coil and turn "cold".
Without air moving through the condenser you might as well run the compressed R134a through a pipe. (same result).
The high pressure switch will shut down the compressor clutch.
I think you and me are chasing down the same issue on these jobs.
Why doesn't the cooling fan turn on when the A/C is turned on?
In my case, I have 2 fans, 2 speeds, and 3 fan relays in the engine compartment fuse box. (fun)
Good points, but minor nit, old AC systems use expansion valves, not just new ones. My 50-year-old station wagon has one, as does my 24-year-old daily driver. The latter has a failed condenser fan so AC doesn't work well on a hot sunny day in traffic. (The old wagon never had a condenser fan, they were not used on R12 systems.)
Like I said. I'm not an A/C guy. I didn't mean to give any bad advice.
Not a big deal and it doesn't really affect the good advice, for most AC troubleshooting it probably doesn't make a heck of a lot of difference whether an expansion valve or orifice tube is involved - if either clogs, things stop working. (There may be fine points to be aware of but I'm not a pro either.) Also it is not likely many people here will be working on ancient R12 systems that were not equipped with condenser fans.
System pressure is affected by humidity as well as temperature. Don't forget after the engine is running for a while underhood temperatures rise, and how quickly the condenser can shed heat is also a factor. I don't think your pressures are out of line. Did you check the condenser fan, which is normally mounted right on the condenser behind the grille? On an R134a AC system failure of the condenser fan is a very common cause of cooling loss when the car is not moving. (It happens on mine but the fan is such a PITA to change I haven't bothered even though I have the part.) Another potential problem is condenser loaded up with debris or cooling fins bent and closed up.
If I’m not mistaken, the fans that Cool my radiator also cool the condenser on the front side. They both come on and turn off, but I have no idea if they are working as intended. What if I purchased a universal cooling fan to mount on the other side of the condenser that was wired to stay on when the air conditioner is running?
also, I’ll have to say there’s a bit of a wear on the fins on the bottom where the fog lamps are. I don’t run my fog lamps, but obviously that part of my condenser has been bombarded with bugs attracted to the fog lights Which were run by the previous owner
I just checked the Rockauto database for your car and it does list a condenser fan motor. HOWEVER, I found a youtube video showing condenser replacement on an '06 Matrix and it shows no fan on the condenser itself. So maybe on that car the "condenser" fan is actually on the radiator side. Scotty would know for sure since he has one of these cars and has no doubt worked on quite a few.
https://www.youtube.com/watch?v=VFOQhYExUaM&t=63s
Yes. There’s one big fan On the radiator side. For some reason I thought it was double fans but it’s just one. When I got home from my test drive, The fan was engaged as I tried to check and see if the condenser was kicking in. I don’t see so well in the dark even with a flashlight, but I don’t believe it was.. The Electric fan was blowing the whole time though
First time I've heard of an AC system designed for R134a not having a pusher fan right on the condenser, but I'm not a pro and have only worked on a handful of different models.
Update:
Yesterday the air worked once for a short time and then stopped working. Since then up until today, it has not worked at all. Just to be clear, the fan blew hot air. I called my mechanic and asked him if he could test the voltage going to the AC while it wasn’t working. Sure enough, there was no current going to the compressor. Yesterday I had done a little research and found that there is a clutch control relay for the compressor. My mechanic removed the horn relay and plugged it in to the clutch control relay socket. The Compressor kicked in instantly. He found another relay in his junk drawer and plugged it into the horn socket. So for now I have Cold air and a horn… albeit not a very masculine horn.
I went ahead and bought another relay from Napa to carry in the glove box. Is it normal for a relay to go out intermittently? Or is it more likely I have an intermittent problem that finally blew my relay?
Probably just a bad relay, that would definitely cause the symptoms you experienced. Keep an eye on it.
Is it okay to swap and test relays while the car is running/on?
I wouldn't do it, too much in the way of electronics involved, a voltage spike could kill a module.
We hot-swapped the relays, but could be we got lucky. The horn socket is always hot unless you disconnect the battery
Might be OK, but why take the chance? There's probably a module controlling the relay and a spike from live insertion can damage driver transistors. I'd put this in the category of "You got away with it this time but don't try it again!"
Agreed
did you check the blend doors?
I did not check the blend doors, but as far as I can tell when the compressor is running And the magnetic clutch engaged, air is blowing cold.
For some reason, answers and comments are not showing up in chronological order. That can be confusing. Thank you, everyone, for your comments and suggestions and help.
The user interface here can be a bit confusing! Keep us posted as to whether the relay winds up being a long-term fix.
The compressor doesn’t seem to be coming on at all now. I probably overloaded the system.
Another thing I’m concerned about is shortly after I got the vehicle, I replaced the cabin air filter. Besides being filthy, the old one was covered in leaves, debris, acorns, sticks, etc. I hope the evaporator is ok.
Sounds like some pressure safety switch may have been triggered. See if it comes back on once everything is cooled down.
Another thing to consider is that if your compressor is a variable displacement type you cannot tell whether you're low on refrigerant by system pressures (unless it's near empty). The compressor will keep pressures up even with little refrigerant in the system but it will still not cool properly. That car is listed as having a Nippondenso 10S17L compressor but I was unable to determine if it is variable displacement with a quick search.
Your evaporator should be OK as far as being clogged up if the filter kept all that stuff off it.
The underside of the old dirty filter was clean looking. I guess all I can really do at this point is to take it to a shop, have it vacuumed, and have the refrigerant replaced to spec. There are a couple of places here who will put it on some sort of machine for that. I’d still like to learn why it’s been shutting off when idling. I think I can rule out the cooling fan.
If it's a variable displacement compressor then evacuate and refill is really the only way to know you have the correct refrigerant charge, though you can sometimes get away with adding a little at a time if it's a bit low.
Does the compressor actually shut off when idling or does it remain engaged and the cooling becomes inadequate? Looking back at your original post it's not clear.
Hopefully Scotty will see this and can chime in since he's had experience working on those cars. Since I have not I can only offer generic suggestions.
Keeping AC working can definitely be a challenge on an old car.
That’s a good question. At this point I am not sure When the compressor was running because the compressor did not seem to be kicking in at all after I messed with things. And previously when the AC stopped blowing cold, I wasn’t in a position to get out of the car and look at it. I assumed over Time the refrigerant became just a little low, and that was probably the source of my problem. We know what happens when I assume…😉
Thank you for sharing your thoughts and experience, Chuck!
Just finished a banjo gig at Martin Methodist College in Pulaski Tennessee. My 13-year-old son wanted to go to the skate park. It’s a fairly mild 80° day. But, I’m sitting in the sun with the engine idling and the air running. Thermometer in the vent says the air temp is 42°-43°. Seems to be working fine. It’s not very humid out. Humidity seems to be a factor. Squirrley air conditioner
Sounds like it is performing as it is supposed to for the moment. Keep an eye on it.
In comparison mine works fine up into the low 90s with the condenser fan not working. As outside temperature gets hotter the AC falls off very noticeably at stoplights and picks up again while moving. (I just live with it because I don't feel like taking out the radiator, oil cooler, and turbo intercooler, then moving back the condenser hoping nothing breaks in order to replace the danged fan.)
When we left the park, as I was driving through the neighborhoods, the air started getting progressively warmer coming out of the vents. I thought maybe it would cool again when I got out on the highway where I could get my speed up. Nope. It just quit blowing cold. At that point, I turned the AC off and put the windows down. When we were a little over halfway home, I rolled them back up and turned on the AC. It worked the rest of the way home. Squirrley
Would be interesting to see whether the compressor is still running when that happens or if the compressor clutch just disengages for some reason. If the latter it may well be an electrical type problem.
The AC on my matrix is still behaving erratically. My local mechanic agrees that the pressure in the system is fine. Sunday it pretty well blew cold all day. Last night and today it blew mostly warm air. Also, when the Air temp in my vents is warm, the compressor is not kicking in. Looks like the clutch plate is not engaging. The fan is blowing just fine on the condenser.
If there are any inexpensive parts that would fail and cause The compressor to shut itself off, I would be willing to replace them just to see what happened. I feel a lot differently about a vehicle with working AC compared to one that doesn’t. Having thoughts of driving it into the duck river
A prime suspect would be the low-pressure cutout switch or its wiring. Or the computer module controlling it. Another possible issue would be the compressor clutch coil intermittently failing due to heat and vibration.
All the electronics on modern cars adds an extra layer of complexity to deal with. The AC on my '71 Ambassador is a lot simpler to work on. No computers, no scan tools needed, it's just controlled with simple electrical switches - essentially like Scotty's hotwiring workaround but it came that way from the factory.
Perhaps I should try to find a reputable shop who will vacuum my system and restore the refrigerant and oil to factory specs. That will get me a baseline, then rule out a failing compressor or clutch. If that doesn’t fix it, it’s time to bypass the electronics.
There is something to be said for knowing that you have the correct amount of refrigerant since R134a systems are sensitive to even a small undercharge or overcharge. Still, seeing as how your AC does sometimes work OK my money is on an electrical type problem.
Day two of trouble free cold air. Must have just needed a little refrigerant and a new relay. We’ll see how the weekend goes. Got a few gigs…