Need AC expertise HELP!

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Blk00ss

Full Access Member
Joined
Jan 22, 2022
Posts
151
Reaction score
217
Late last year we noticed my son's '05 not blowing cold. Upon further investigation I discovered the compressor kicking on and off. Made sense, I suspected it was low on R134a. But, it was getting late in the year and cooler so we decided we would deal with the issue this spring. Today I bought AC pro with a gauge. It was low, way low. After pumping a good majority of the 20 oz can into it, we finally got the compressor to kick on/ off, on/ off. It did this for a while and I continued to add refrigerant. Finally the compressor would stay on and the air coming out was gradually getting cooler. But here is the odd part...when the cooling fans kicked on (we were in garage and it was warm), my AC Pro gauge would drop from green, back to white (low) and the compressor would start kicking on and off again. I'd fill it back to green (or close), cooling fans kick on, gauge again goes from green to white (low) and compressor starts kicking on and off again. I finally gave up

Anyone have any idea why the cooling fans kicking on would make the pressure go back down to a level where the compressor won't stay on?
 
OP
OP
B

Blk00ss

Full Access Member
Joined
Jan 22, 2022
Posts
151
Reaction score
217
Update...my son had an errand to run roughly 15 miles round trip. I told him while he was driving, keep the AC and recirc buttons on just to allow the refrigerant to run through the system. He got home and his AC is much colder, and is staying on.

Maybe it just needed more time for the refrigerant to cycle through the system?

Guess I'll check it again tomorrow. But I have no doubt that it needs more R134a. I believe this system holds 28.8oz dry. And ours was so low when we started this, the compressor wouldn't even cycle on and off. It wouldn't click on at all.

Still don't understand why pressure would drop when cooling fans kicked on though
 

swathdiver

Full Access Member
Joined
May 18, 2017
Posts
18,721
Reaction score
23,967
Location
Treasure Coast, Florida
Update...my son had an errand to run roughly 15 miles round trip. I told him while he was driving, keep the AC and recirc buttons on just to allow the refrigerant to run through the system. He got home and his AC is much colder, and is staying on.

Maybe it just needed more time for the refrigerant to cycle through the system?

Guess I'll check it again tomorrow. But I have no doubt that it needs more R134a. I believe this system holds 28.8oz dry. And ours was so low when we started this, the compressor wouldn't even cycle on and off. It wouldn't click on at all.

Still don't understand why pressure would drop when cooling fans kicked on though
The short wheelbase models with rear AC I thought had a 2.5 pound refrigerant capacity.

Pressure changes when the fans turn on.

@91RS
 
OP
OP
B

Blk00ss

Full Access Member
Joined
Jan 22, 2022
Posts
151
Reaction score
217
The short wheelbase models with rear AC I thought had a 2.5 pound refrigerant capacity.

Pressure changes when the fans turn on.

@91RS
I belive its 43oz with fonrt and rear AC, which we do have. Which also means, we're still quite low.

I think you're right about the fans. I was not prepared for that. In all the videos I watched, reading I did I did not see antying about the pressure dropping when cooling fans kicked on
 

Mean_Green

Full Access Member
Joined
Mar 23, 2023
Posts
329
Reaction score
443
The bigger question is WHY is it so low? AC systems are supposed to be closed. Low gas means a leak somewhere. How bad of a leak and where it is might make a difference in whether or not a self recharge will last very long.
 

swathdiver

Full Access Member
Joined
May 18, 2017
Posts
18,721
Reaction score
23,967
Location
Treasure Coast, Florida
I belive its 43oz with fonrt and rear AC, which we do have. Which also means, we're still quite low.

I think you're right about the fans. I was not prepared for that. In all the videos I watched, reading I did I did not see antying about the pressure dropping when cooling fans kicked on
If the AC sticker is still under the hood it'll have the capacity. The generation after yours is what I posted. Let me see if I have a copy of my sticker...

20190807 - Underhood AC Sticker.jpg
 
OP
OP
B

Blk00ss

Full Access Member
Joined
Jan 22, 2022
Posts
151
Reaction score
217
The bigger question is WHY is it so low? AC systems are supposed to be closed. Low gas means a leak somewhere. How bad of a leak and where it is might make a difference in whether or not a self recharge will last very long.
I would imagine it has a leak. I mean, its 18 years old. Yes, I'm aware the R134a we put in may just run back out. Its not the end of the world. If that happens, then I'll know there is a good size leak that needs to be addressed. But if we do add R134a, and it blows cold till fall, then that'll work for me.
 

Mean_Green

Full Access Member
Joined
Mar 23, 2023
Posts
329
Reaction score
443
I haven't tried mine yet. There is a note that says the rear seat portion was disconnect, but not why.


I don't know what to expect.
 
OP
OP
B

Blk00ss

Full Access Member
Joined
Jan 22, 2022
Posts
151
Reaction score
217
Let us know what happens when you inspect tomorrow.
Added another 12oz can. system was still cycling on and off every time cooling fans would kicked on. But once I added enough to where the needle would stay in the green, the system stopped cycling on and off. It needs more as the needle is on the very edge of green. But it blows incredibly cold now, and doesn't cycle off an on. Hopefully it lasts a bit. We'll see. Just glad the issue was obviously related to low refrigerant and not the compressor taking a crap.
 

Forum statistics

Threads
125,954
Posts
1,757,819
Members
87,857
Latest member
Kanali
Top