Wife's G4 just had the battery light come on again after 2 years.

[Fummins]

Right back to square one. It might be the engine replacement did this AC in.

When car is in motion, park, or neutral I can hear it cycle on and the cabin is cooling off.

When idling in drive with my foot on the brake, it starts to blow much warmer air.

My mechanic has given up at this point.

What in the world could produce these conditions?

Improper refrigerant level would be my guess. I would give up with your guy and take up 7milesout on his offer.

[7milesout]

Lack of specified quantity of refrigerant. Refrigerant pressures are ... beside the point. I guess a "weak" compressor could also cause this. But it is like 10 time less likely to be a worn out compressor.

[Top_Fuel]

When car is in motion, park, or neutral I can hear it cycle on and the cabin is cooling off.
When idling in drive with my foot on the brake, it starts to blow much warmer air.

Wait...I thought the symptoms were that it cools great when the car is moving, but not so well when the car is sitting still.

Now you are saying that it cools fine whether it's moving or sitting still (as long as it is in park or neutral). But as soon as you put it in drive (without moving) suddenly it doesn't cool as well?

<Must resist urge to ask more questions>

I will bust out my thermometers to get some actual temp readings from my AC vents. My car doesn't cool as well when it's sitting still. The vent temp does go up slightly when the car isn't moving...which is normal. The air is "less cold" but it's not warm. But you might think it's warm. That's why we need to start talking actual temps.

[7milesout]

Top Fuel - Over the past 10 days or so, it has gotten stifling hot down here in the dirty dirty Thunderdome. Very humid. Agreeing with everything you said. But down here, at idle it's probably going to be reasonable to get warmer with the car in gear sitting still, than what you experience.

It's normally hot in the summer. But as of late, the heat was paired with high humidity and little to no wind (stifling). Really taxed A/C systems. If they're not working optimally, people will notice.

But you point out something interesting. Could Dirk's compressor be kicking off (and not even cycling) when sitting still in Drive? Hmmmmm, easy to determine though.

Dirk - I haven't been driving the Blueberry over the last 10 days. My middle son is using it to run back n forth to KSU over this summer. Says the Blueberry is growing on him. And no cooling complaints from him. He's more of an A/C princess than I am. I'm windows down until I'm breaking a sweat.

[Fummins]

Well I think I have a temp probe for one of my cheapo multi-meters. I'm gonna go check the car that I just filled with a can oh' ac. It's only 62F here right now so there's that...

UPDATE:
I just checked this car. My probe showed outside temp of 20C. Put the probe in the lh center dash vent. Temp dropped quickly down then bounced between 9.7C(49.46F) and 10.7C(51.26F) as the compressor cycled. I did this with with the car stopped while in Drive. Compressor cycled on and off ever 20-30 seconds nothing crazy.

I'll try it again on a "warmer" +25C(77F) day.

[Top_Fuel]

Over the past 10 days or so, it has gotten stifling hot down here in the dirty dirty Thunderdome. Very humid.

I just got back from a few days in Tampa. It was just the usual hot...but you're right...the humidity was off the frigging charts crazy uncomfortable. Maybe the worst I can remember. I rented a brand new Chevy Malibu and that friggin' AC was set on max/recirc/61 degrees the entire time. With a huge black dashpad and no tinted windows, it was fighting to keep the car comfortable. I don't think my Mirage AC would do very well down there.

[Fummins]

I just zoomed in on those charts that Christopher(?) posted. It shows that if it's 95F out and relative humidity is between 30-80% then vent temps of 61.7F and 84.4F is acceptable. If it's 104 outside then don't expect it to blow out the vents air that's cooler than 70.

[7milesout]

I just zoomed in on those charts that Christopher(?) posted. It shows that if it's 95F out and relative humidity is between 30-80% then vent temps of 61.7F and 84.4F is acceptable. If it's 104 outside then don't expect it to blow out the vents air that's cooler than 70.

I don't know if I would ever consider 84.4°F acceptable. My Lexus can / will destroy that. That sucker performs. Anywho - apples / oranges.

These latest threads remind me of something. A few years back, my sons and I flew to Las Vegas. We Turo'd a G4. It was the middle of summer. And we took the car to Death Valley. I A/C'd that sucker like a son-of-a-gun. It wasn't mine, I didn't care.

And yes I can say there there were instances in Death Valley where the A/C did not keep us perfectly comfortable. And, at some point after pushing the car very hard, full A/C etc., it gave off a smell that made me feel ... uneasy. It smelled like something under the hood was just barely starting to smoke. At that point, I backed off the car and let it run easier, but still with full A/C. The smell did not go away until some time after leaving Death Valley.

It got the job done. But we had been in Death Valley maybe 2 or 3 years before that in our 2006 Honda Odyssey. Same time, middle of summer. The Odyssey handled it better. However, I can say that I didn't push the Odyssey nearly as hard, because I knew that I would want the vehicle to get us 2,000 miles back east across the country. And it did, with flying colors. Great trips, both times.


7milesout

[Dirk Diggler]

I just zoomed in on those charts that Christopher(?) posted. It shows that if it's 95F out and relative humidity is between 30-80% then vent temps of 61.7F and 84.4F is acceptable. If it's 104 outside then don't expect it to blow out the vents air that's cooler than 70.

It was way above 70°, it's warm air and feels way worse than in the new Mirage.

[Dirk Diggler]

Wait...I thought the symptoms were that it cools great when the car is moving, but not so well when the car is sitting still.

Now you are saying that it cools fine whether it's moving or sitting still (as long as it is in park or neutral). But as soon as you put it in drive (without moving) suddenly it doesn't cool as well?

<Must resist urge to ask more questions>

I will bust out my thermometers to get some actual temp readings from my AC vents. My car doesn't cool as well when it's sitting still. The vent temp does go up slightly when the car isn't moving...which is normal. The air is "less cold" but it's not warm. But you might think it's warm. That's why we need to start talking actual temps.

The air it was blowing at idle had to of been over 85° it got hot fast.