Odd AC Event Today

ALLEGRO

ALLEGRO

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I had been sitting in a parking lot in the Memphis area for about an hour, talking on the phone, when all of a sudden I noticed it was getting hot in the Limited.

I was showing 92 for an outside temp, and all had been good leading up to this event.

I noticed that while set in AUTO mode, the fan had gone to HI and the air coming out of the vents was warm, turning to hot. Water temp was indicating normal.

I increased the RPM's to about 1500 or so, but nothing changed. I turned OFF the ignition and re-started the engine. Still no improvement.

I decided to keep the RPM's up a bit, and re-gather my thoughts to go to the dealership for evaluation. Well, just about then, I notice a short burst of cooler air. It returned to hot, but then another cool shot.

Wanting it to do it at the nearby dealer, I began to leave the lot and head that way. Then, like a gift from God, it was cool, and stayed that way. I drove home some 35 miles and all was and is good.

Summary: I wonder if I just got the head-pressure high enough at idle to shut down the compressor? Either that, or the cooling fan is failing or did fail. It seems to be back to working if it was that, but it is a possibility.

Okay, all you GURU's........YOUR TURN.
 
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Wow, there seems to be so many A/C-related threads lately.

I think either of your suggestions could be possible...If you are sitting still idling the engine, then the fan clutch MUST be engaged to keep air moving through the condenser. If for some reason the fan wasn't spinning, then the A/C temp would definitely rise. Then again, the coolant (water) temp of the engine would also rise rapidly. So if your A/C started blowing hot, but your engine stayed at normal operating temp, chances are the fan was working properly.

My guess is that your compressor stopped cycling for some unforeseen reason. I do know that the evaporator can freeze on a vehicle that has its A/C clutch engaged too long, but that's exactly why the compressor clutch is supposed to cycle on and off. And of course a low refrigerant charge can cause the cycling to become more rapid than normal. Have you done any A/C servicing lately?
 
The AC system has not been serviced at all. I just assume that since I always run it in AUTO at 74 degrees, the fan seems to always move down to either LOW or 2 (of 4), and it always makes me happy, that all is good.

If it does it again, I will for sure take her in for a checkup.

Thanks for the response.
 
I have an 04 limited and I've had a similar thing happen. While driving using auto AC I have had it suddenly get warm and like you mentioned it takes a while before I register that something is wrong. When I look at my AC controls I have noticed that the AC light has turned off...everything else is normal, same temps listed, same fan speed, same everything except no AC and no AC light. All I have to do is hit the AC button and all fixed. My runner has done this maybe 5 times in the last 6 months. Cant explain it. Once or twice this has happened after sitting in a parking lot for an extended period of time.
 
It almost sounds like a high-pressure cut out event. Was there any breeze? Were you parked with a slight tailwind?
 
CJ3Flyr said:
It almost sounds like a high-pressure cut out event. Was there any breeze? Were you parked with a slight tailwind?
Click to expand...

We are in the throws of another Mid South Summer.

Temps go to about 100 everyday, and the humidity is at least 50%. Today was a wind-less day, so, like you, I am betting on a head pressure issue, probably from either a freeze-up or lack of circulation at idle speed.

Now the questions are: will it return, and have I done other damage?
 
Happened on my Dodge Ramvan many summers ago. Was sitting in a parking lot with the AC going for an hour and a half or so and it did not fix itself until we were driving for a good 10 mins. Never happened again, never seemed to cause any problems (it still works fine today). I chose to forget it, and not run my A/C while parked for 1+ hours. If you find out something is wrong, post up. Otherwise, to me, it's just one of those "this is what happens when you do that" things. If I don't do "that," then "this" doesn't happen :D
 
ALLEGRO said:
sitting for about an hour....air coming out of the vents was warm, turning to hot. Water temp was indicating normal.
Click to expand...

Had an experience similar to yours in July 2007 while poking around some old mine areas and leaving the truck idling between stops. The driving was just a crawl between stops so not much chance of getting air flow. AC just seemed to quit working. It was about 110 degrees that day and dead calm. No change in the coolant guage, but it makes me wonder about it because I've never seen it higher than its standard max set point. Next day, it was like nothing had happpened and A/C has continued to work fine since.

So, I guess there are limits to what the A/C can do. There went my plans to run some quick release ductwork from the 4runner into the house. :bigok:
 
There was some horrible story in SW Florida a couple of years ago. A police dog died in a Tahoe due to one of these 1+ hour sits that equated to a high pressure cutoff tripping.:wow2:

Last I heard Lee County was installing remote starts with the FOB that has a very long-range/paging capability and it reports cabin temp to the FOB.
 
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Two more days without a problem. I think everything is okay.....but still nervous.

Here's what I have concluded:

I use the AUTO feature, which allows the HVAC fan to run as slowly as necessary. In that all was good until the issue, I think that the fan was on LO, not moving much air past the interior coils and obviously not much air going past the condensor at idle speed.

What I think is that the combination of these two things caused the HIGH pressure switch to trip, probably due to freezing of the system. After a bit of time to regulate, it has returned back to normal.

I still can run in near 100* heat, on AUTO set at 74* and the fan will "eventually" move downward to the LO or 2 position. I assume the system is adequately charged to achieve this, so at least at this point I am not taking her in for service.

More as it happens...........
 
Well it has been over a week now, and the problem has not repeated itself. I have talked with several people, and all my earlier possibilities are still in play.

I am just going to continue to run it, as set on 74* and AUTO, I still get good cooling to my liking. I am convinced that the system is NOT as strong as I would like for it to be, but what is is what is.

Chime in if you too are having cycling issues or total drop-out of AC
 
104 degrees here in NY today and the 4Runner's A/C is keeping me cool as an Eskimo. No issues at all!
 
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