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Discussion Starter · #1 · (Edited)
Now that summer is coming up fast and day temps are going up, plus travel is increasing post COVID disruptions, I found out today that the A/c was not cooling the car. There is a hint of cool air coming from the vents but it is not what it used to be. In fact it may have been going out over the past 1.5 years as I found that it took longer and longer to cool the car but today it was very clear that this needs to be tackled immediately.

2004 Corolla, 170K miles. I live in the west coast of Florida, Tampa. A/C is desperately required.

Things I have checked -

1) Cabin air filter is clean. There were a couple of leaves on it and some pollen things on it. Definitely not anywhere near clogged.

2) Started the car, turned the A/c on full blast with air recirc. The high pressure line was cool to touch, felt a touch cooler than a metal surface in a AC room. The low pressure line between the evaporator/accumulator and condenser was a bit warmer than the high pressure line but still cool.

3) The low pressure line between the compressor and the condenser is hot. Hopefully I am describing the lines correctly. In case there are any mistakes, let me know and I correct them in this OP.

Last time I went to the dealer, co-incidentally or not, about 1.5 years back, the Service Adviser recommended evac and refill of the AC system due to age (and only this). I was getting new tires for the car. Sabotage does lurk at the back of mind.

What should be the line of approach for finding the leak? All inputs are appreciated.
 

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I would first check for leaks. Either get tested or take in for recharge. If leaking, excellent time to service the collector, dryer and O rings .

Does the compressor clutch activate when ac is turned on? And does ac light come on?
 

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You can put dye in the ac to locate a leak.

Get a temp gauge and measure the temperature of the air coming out of the vents.

What you might be looking at is a heater core blockage or the ac compressor is starting to show it's age.

What's the current condition of your condenser? Anything blocking it?
 

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Now that summer is coming up fast and day temps are going up, plus travel is increasing post COVID disruptions, I found out today that the A/c was not cooling the car. There is a hint of cool air coming from the vents but it is not what it used to be. In fact it may have been going out over the past 1.5 years as I found that it took longer and longer to cool the car but today it was very clear that this needs to be tackled immediately.

2004 Corolla, 170K miles. I live in the west coast of Florida, Tampa. A/C is desperately required.

Things I have checked -

1) Cabin air filter is clean. There were a couple of leaves on it and some pollen things on it. Definitely not anywhere near clogged.

2) Started the car, turned the A/c on full blast with air recirc. The high pressure line was cool to touch, felt a touch cooler than a metal surface in a AC room. The low pressure line between the evaporator/accumulator and condenser was a bit warmer than the high pressure line but still cool.

3) The low pressure line between the compressor and the condenser is hot. Hopefully I am describing the lines correctly. In case there are any mistakes, let me know and I correct them in this OP.

Last time I went to the dealer, co-incidentally or not, about 1.5 years back, the Service Adviser recommended evac and refill of the AC system due to age (and only this). I was getting new tires for the car. Sabotage does lurk at the back of mind.

What should be the line of approach for finding the leak? All inputs are appreciated.
The line between the compressor and the condenser is a high pressure line. It's sometimes called a discharge hose.
XtRaSlo and 75aces made a good suggestion: Check for leaks.

Two ways of doing this are to use an electronic leak detector (sniffer), or inject dye into the system. Dye is typically added to the system during a recharge, although there are "injectors" which attach to the low pressure port (ALWAYS use the low pressure port when servicing). My '79 Celica had multiple problems when I fixed the A/c three years ago. I had a leaky discharge tube (found the leak with dye and u/v light). I thought I was home free, and found the cooling didn't last too long. I hooked up a manifold gauge set, and noticed the low pressure side indicating a vacuum. I bought a leak detector, and found another leak inside the cabin. That turned out to be a leak at the electrical prongs on the pressure switch. Dye would not have found that one.
The reason for the vacuum on the low pressure side was a stuck closed expansion valve. So not one but three problems.

I'm not a mechanic, but I did get my 609 certification so that I could buy R12. If I had to do it again, I would have paid an A/C shop.
 

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Discussion Starter · #7 ·
I would first check for leaks. Either get tested or take in for recharge. If leaking, excellent time to service the collector, dryer and O rings .

Does the compressor clutch activate when ac is turned on? And does ac light come on?
The clutch activates for now. However, if the leak continues, the system might not allow the compressor to engage but thats down the road.
 

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Discussion Starter · #8 ·
You can put dye in the ac to locate a leak.

Get a temp gauge and measure the temperature of the air coming out of the vents.
I dont have a temp gauge for now. However, the air felt to be about about mid 70s wneh the outside temps were in mid 80s. Definitely not anything close to 40s, which I have experienced in this car. I used to have to direct the vents away from my face and hands while driving.

What you might be looking at is a heater core blockage or the ac compressor is starting to show it's age.
Anyway to verify that? The air turned hot when I turned the dial all the way to HOT.


What's the current condition of your condenser? Anything blocking it?
One thing I noticed on the condenser was whitish kind of oblong blob about the size of a quarter on the inside face. On the side facing the front, I have a thin wire meshzip tied to prevent debris hitting the coils. This has been in place for about 7 years now.
 

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Discussion Starter · #9 ·
The line between the compressor and the condenser is a high pressure line. It's sometimes called a discharge hose.
XtRaSlo and 75aces made a good suggestion: Check for leaks.
Something new I learned today. Thanks


Two ways of doing this are to use an electronic leak detector (sniffer), or inject dye into the system. Dye is typically added to the system during a recharge, although there are "injectors" which attach to the low pressure port (ALWAYS use the low pressure port when servicing). My '79 Celica had multiple problems when I fixed the A/c three years ago. I had a leaky discharge tube (found the leak with dye and u/v light). I thought I was home free, and found the cooling didn't last too long. I hooked up a manifold gauge set, and noticed the low pressure side indicating a vacuum. I bought a leak detector, and found another leak inside the cabin. That turned out to be a leak at the electrical prongs on the pressure switch. Dye would not have found that one.
The reason for the vacuum on the low pressure side was a stuck closed expansion valve. So not one but three problems.
Can this sniffer thing be rented/loaned?

I'm not a mechanic, but I did get my 609 certification so that I could buy R12. If I had to do it again, I would have paid an A/C shop.
 

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Discussion Starter · #10 ·
Clean the coils of your ac condenser located behind the front bumper.
Okay, okay. I guess the universal opinion is to check the condition of coils. I will cut the zip ties holding the mesh and check the coils. I can always ziptie them back. Thanks for emphasizing it.
 

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Discussion Starter · #11 ·
You can rent a manifold gauge set from the local auto parts store and measure the pressure.

You can open the cap on the low side and spray soapy water. If you see bubbles, it's leaking at the port.
I will get the guages tomorrow or soon and check them out. The soapy solution seems to be something I can do even without any tools. Can I put it on all the AC system components visible? Cant see a reason why not.
 

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Discussion Starter · #12 ·
Any ideas on what dye to get? I would also need some 134 to add the dye, right?
 

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You might also want to verify the electric fan/s at the radiator come on when the AC is switched on.

Any competent AC shop will know how to check for leaks. It's routine for them to make sure the system holds a vacuum for at least 20 minutes before recharging your AC system. That test won't rule out a very slow leak so they will probably add some dye as others suggested so if you need to return they'll be able to find the leak. Good luck and let us know what the solution turns out to be.

EDIT:. If you plan on doing this yourself you'll need a set of gauges and a vacuum pump, both available at Harbor Freight. You'll also want to watch a few Youtube videos on recharging & leak finding. I usually buy my 134 at Walmart for about $5 a can. You can get dye at an auto parts store. If all you need is a recharge it's probably cheaper to let a shop do it.
 

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Discussion Starter · #14 ·
You might also want to verify the electric fan/s at the radiator come on when the AC is switched on.

Any competent AC shop will know how to check for leaks. It's routine for them to make sure the system holds a vacuum for at least 20 minutes before recharging your AC system. That test won't rule out a very slow leak so they will probably add some dye as others suggested so if you need to return they'll be able to find the leak. Good luck and let us know what the solution turns out to be.
I was hoping to give it a shot first, and then if need be to go to a shop. Whichever way it turns out, I will post the final status. (y)
 

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I will get the guages tomorrow or soon and check them out. The soapy solution seems to be something I can do even without any tools. Can I put it on all the AC system components visible? Cant see a reason why not.
The ac does need to be on in order to see the air bubbles. That actually happened to me once. Saliva works too. Never actually tried it though.

Realistically, the only access is the high and low side ports. Unless you actually disconnect the hardlines from the firewall and the compressor.

IIRC, the ac lines are thin tube. Just inspect the lines as best you can. Just to see if there's any cracks. It's not probable in florida, but you never know.

Ask the guy at the parts store for ac dye.

Edit : you could try the ac in a can. Just to see what the compressor will do. If it works for a day, it's holding pressure. But, if it stops working the following day, there's a big leak in the system. The dye will show you where.
 

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Okay, okay. I guess the universal opinion is to check the condition of coils. I will cut the zip ties holding the mesh and check the coils. I can always ziptie them back. Thanks for emphasizing it.
Does it blow cold when you are driving it at higher speeds? When you are sitting, is that when it doesn't blow cold enough?
 

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Be careful touching those tubes especially near the compressor. They can get hot and cause scald injuries.

I'd check the two pipes near the firewall on the passenger side. The thicker one is the return low pressure pipe and the thinner one is the liquid high pressure pipe. The low pressure pipe should be cold (~40F or so) and the high pressure pipe should be warm to very warm depending on the heat load, but still be careful touching it.

Before you do anything, put the manifold gauge on there and read off the pressures at 1500 rpms. If you have a kitchen thermometer, measure the center vent temp on high fan speed and recirc mode. See what the vent temp is. In a normal system, I'd suspect it's just lost some refrigerant over the years and just got to the point where you noticed it.

The earliest year I could find is 2009. For that year Toyota reported a normal leakage rate of 15.5 grams per year. Or about 1/2 oz. I'd estimate you've lost 2021-2004 = 17. 17 / 2 = 8.5 oz. Use that as an upper limit, but if you top off (see Eric's video below), charge a few oz at a time and allow the system to stabilize, don't go all in with the whole can. That can jack up the system fast. The 2009 system holds only 440 grams of refrigerant.

AC leakage rates:

I'm not sure if your model year still has the sightglass to allow you to see refrigerant movement inside the high pressure line. IMO it's a useful tool. And be careful working with refrigerants, it can flash freeze flesh and eyeballs in less than a blink! Search up and read up on safety precautions.

FYI:




I will get the guages tomorrow or soon and check them out. The soapy solution seems to be something I can do even without any tools. Can I put it on all the AC system components visible? Cant see a reason why not.
 

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Now that summer is coming up fast and day temps are going up, plus travel is increasing post COVID disruptions, I found out today that the A/c was not cooling the car. There is a hint of cool air coming from the vents but it is not what it used to be. In fact it may have been going out over the past 1.5 years as I found that it took longer and longer to cool the car but today it was very clear that this needs to be tackled immediately.

2004 Corolla, 170K miles. I live in the west coast of Florida, Tampa. A/C is desperately required.

Things I have checked -

1) Cabin air filter is clean. There were a couple of leaves on it and some pollen things on it. Definitely not anywhere near clogged.

2) Started the car, turned the A/c on full blast with air recirc. The high pressure line was cool to touch, felt a touch cooler than a metal surface in a AC room. The low pressure line between the evaporator/accumulator and condenser was a bit warmer than the high pressure line but still cool.

3) The low pressure line between the compressor and the condenser is hot. Hopefully I am describing the lines correctly. In case there are any mistakes, let me know and I correct them in this OP.

Last time I went to the dealer, co-incidentally or not, about 1.5 years back, the Service Adviser recommended evac and refill of the AC system due to age (and only this). I was getting new tires for the car. Sabotage does lurk at the back of mind.

What should be the line of approach for finding the leak? All inputs are appreciated.
Check the pressure of the freon gas at any A/C repair place. The other thing . . . any odors in the car like chemical smell? That would indicate the A/C evaporator (under the dashboard).
 
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