help me with my car's air conditioning

mentaluproar

macrumors 68000
Original poster
May 25, 2010
1,731
130
Ohio, USA
So I bought this car last year, a 2003 toyota echo, and have found that the A/C blows cool, but not cold air. it works best on the freeway, but in the city, not so much. I assumed it just needed some refrigerant. When I went to add some, A/C running, compressor engaged, I found it the low side running at 55 psi. That seems a bit high, right? Supposedly, an active system should be running 25 to 40 psi on the low side, with 30 being ideal.

I dropped it down to 35 psi until I figure out what to do and now the A/C doesn't so squat. Do you think whoever overcharged it already caused damage to the system? What can/should I do now?
 

MovieCutter

macrumors 68040
May 3, 2005
3,342
2
Washington, DC
I have the same problem on my 15 year old Honda CRV. It blows cold when I'm accelerating or the the RPMs are 1k and up, but idling, it just blows warm air. I only use it once or twice a week so I haven't seen the point in taking it in, but curious to see of anyone has an answer. May also want to try these guys.
 

mentaluproar

macrumors 68000
Original poster
May 25, 2010
1,731
130
Ohio, USA
I'm asking in a few other forums and onle directed me a a page mentioning my vehicle. The part that gets me is this quote:

"The low side pressure gauge will read hi when you initially hook it up when you start the engine and turn the air conditioner on it is designed to drop down to about 30 or 35 psi."

I can't figure out how to read that. When will the system drop the pressure to the 35 mark? When will I get an accurate reading out of this?

I think I'm in over my head.
 

mentaluproar

macrumors 68000
Original poster
May 25, 2010
1,731
130
Ohio, USA
I'm still doubtful the compressor is dead. That it made a noticeable difference when I hit the AC button tells me that its mechanically sound.
 

mentaluproar

macrumors 68000
Original poster
May 25, 2010
1,731
130
Ohio, USA
Apparently, the compressor is dying, but not dead. I'll get another year out of it. Also, I need engine mounts, an exhaust grommet, and new rear axle.

screw
 

prostuff1

macrumors 65816
Jul 29, 2005
1,484
18
Don't step into the kawoosh...
Apparently, the compressor is dying, but not dead. I'll get another year out of it. Also, I need engine mounts, an exhaust grommet, and new rear axle.

screw
I assume they told you why you needed all these parts.

The exhaust grommet can break down, as can the engine mount (though the engine mount is less likely). Needing to replace the rear axle though... that seem odd... unless someone had previously treated the car badly.

Get a second and third opinion and go from there.
 

Tomorrow

macrumors 604
Mar 2, 2008
7,146
1,313
Always a day away
I have the same problem on my 15 year old Honda CRV. It blows cold when I'm accelerating or the the RPMs are 1k and up, but idling, it just blows warm air. I only use it once or twice a week so I haven't seen the point in taking it in, but curious to see of anyone has an answer. May also want to try these guys.
This is a big, big thing to look at, OP. Many cars with smallish engines behave this way.

You have to keep in mind that an A/C compressor can easily rob about 5 hp from your engine. When you're gunning the thing balls to the wall in neutral, that's not an issue; when you're trying to accelerate up a hill, it is. The compressor clutch will disengage for several seconds or more while the drive train needs that power. I suspect this is what's happening in your case.

"The low side pressure gauge will read hi when you initially hook it up when you start the engine and turn the air conditioner on it is designed to drop down to about 30 or 35 psi."

I can't figure out how to read that. When will the system drop the pressure to the 35 mark? When will I get an accurate reading out of this?

I think I'm in over my head.
If what you quoted doesn't make sense to you, then you probably are in over your head.

When you measure the refrigerant pressure on the low pressure side of the compressor (the suction line), it should read around 30-35 psi when the compressor is running. When you first hook up the gauge to the system before starting the compressor, it may read higher than that - which might be why you thought the system was "overcharged."

All this assumes your system runs on R134a, of course. Different refrigerants use different pressures.
 

mentaluproar

macrumors 68000
Original poster
May 25, 2010
1,731
130
Ohio, USA
I assume they told you why you needed all these parts.

The exhaust grommet can break down, as can the engine mount (though the engine mount is less likely). Needing to replace the rear axle though... that seem odd... unless someone had previously treated the car badly.

Get a second and third opinion and go from there.
I asked why, whenever it had to accelerate from a stop, it sounded like a lawnmower. He showed me the grommet had how it was torn, then looked at the engine mounts. Those like eraser heads, and I could see where the tear in the rear one was.

As for the rear axle, I was asking why when I look at the rear the tires are not straight. Instead it looks like |-------\. It sounds, rolls, feels, and handles just fine. He found the bushings were shot, but more interestingly, something came up an hit from the center of the car all the way to the back. it was a ding in that fuel tank, then a scrape all that way back. Then he saw the axle. I think the axle should look slightly bowed upward in the center. It looks like too clean a bend to be from damage, but everything else on it looked fine. He told me that axle would be $1100 in parts alone, and not to bother with it. I rotate my tires regularly, so they will all wear from the inside is all. Still annoys me.

Coincidentally, while looking at the bend, we found the canister purge solenoid that I was suspecting of being the source of that small evap leak that comes back every few hundred miles. the part is $50 online, and the smoke test is $70. He told me that was most likely it, and since I'm handy, I could probably replace that myself and save some money.

I'm getting that smoke test anyway.
 

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