ac sucks at idle

[Jdm5630]

Ive noticed the ac only blows warmer air at stop lights or when its idle. I can leave it idleing and it will never cool down. What gives i know it shouldnt be that bad.

 

[Copper93]

It may be a little low on freon. I know r134 doesn't cool as well as the old r12. I can feel a difference in mine at idle and moving but it will still cool.

 

[stamp11127]

First step in a/c diagnostics is to determine what the low and high side pressures are or at least the low side pressure. Once that is known they will point you towards the next step. You may have a system that is low on refrigerant or a fan clutch that is inoperable. Without knowing the pressures you could end up tossing parts at it until you get it.

 

[04SVT]

^^^agreed. Sounds like it could be a compressor on its way out, buts that's cart before the horse. Get the pressures and it will tell a lot

 

[Jdm5630]

How do i check the presures? I did notice that with it in i can cool air in the front the the rear blows warm air.

 

[stamp11127]

You'll need a set of a/c gauges for r134a refrigerant. If your not going to fix it yourself then getting a set of gauges isn't a good investment. Usually you can get the basic tools for less than the cost of having it fixed. There are plenty of online sites that sell the tools needed, one that I use is Tooltopia.com

Take a look at their a/c tool sets and determine if it is something you want to get into. I'm guessing but I would expect to spend around $600 for the vac pump, gauge set and can tap & possibly a dye set also. If you buy the r134a in the 30lb bottles it is considerably cheaper per ounce than the individual cans per ounce. The last bottle I bought was right at $100.

 

[04SVT]

If you buy a 30# you won't need the can tap but you will want to watch how much you put in. I usually pull a vacuum on the system and charge the whole system by weight.

 

[04SVT]

These are very sensitive to pressure. They aren't like a home unit that can function alright with a little excess pressure.

 

[metaldrgn]

You can rent the gauges and pump from autozone and they give you all your money back.

If your year has an electric aux fan I would check to see if it's turning on. It should turn on as soon as you turn on the ac. If it doesn't have that I would check to see if the compressor is cycling at idle. If not have someone rev up the engine to 1000 then 2000 rpms and let us know if it's cycling and when.

Like stamp said, check the high and low side pressures with the gauges.

 

[tonydiv]

Could also be the condenser. If it's gunked up with debris, it won't let enough air pass over it to work properly at idle. When you're driving, and forcing air over it, it will work a bit better.

Other than topping it up with a can of AC Pro, there isn't really that much you can do (legally) without the proper equipment.

Your best bet may be to just take it to a certified professional.