BurtReynolds

My '00 EX recently exhibited a problem I am trying to wrap my head around.

In the DC area, it has only recently become hot. Real hot this week. I've noticed some wavering on my a/c temp while sitting at lights, but only Tuesday did it really show itself to be a problem.

My commute home is about 40 miles or an hour around here. I was about halfway there when I hit a backup on the Beltway. Up until this point, the A/C was blowing cold, doing its best to cool a black car on a sunny 95 degree day. About a minute or two into my crawl along the highway, the air started warming. About 5 minutes in it was a solid "warm" and I sensed a bit of humidity. It was like this until I got back up to highway speed and then after a couple minutes, it was cool again. I got home, parked in the garage and let the engine run for a few minutes. Air stayed cold.

When I was stuck in traffic, I turned the air on and off to see if it was kicking off on its own or something. I've had the car for 9 years now, and every time I turn the a/c on, the motor responds by kicking the idle up about 100 RPM. Turn it off, and the idle RPM goes down accordingly. The car was still doing this on the highway Tuesday, so it indicated to me that the compressor seems to be turning on, but I got no cold air.

In the garage at the end of the day today and yesterday, both the condenser and radiator fans were running like they should be. My temperature gauge for the motor was normal the entire trip.

Any ideas? The car has run fine in mid-90's heat before, but it is getting older. My only guesses so far is that maybe a radiator or condenser fan is shutting off for some reason? Going 70 when it happens helps mask it, but slowing to a crawl lets it become a problem? Unfortunately you can't exactly tell while in the car on the highway. The only other thing would be if the compressor is overheating and tripping the thermal protector (or maybe a bad thermal protector overreacting?). If the compressor was really shutting off to protect itself, I should notice the uptick in RPM though. So I'm not sure where to look, nor how to diagnose something like the condenser fan shutting off while in motion.

Last night when the motor was cool, I ran the a/c and turned it on and off. The condenser fan kicked on when the a/c did as expected and shut off when the a/c was turned off. No hesitation or anything.

Anyway, just wondering if anyone else has encountered this.

gearbox

iTrader: (95)

are BOTH of the cooling fans working while the ac is on? if not the condenser is not getting cool enough at a stop. when the car moves, air flows thru and it works.

BurtReynolds

Thanks for the response. Both fans are not running every time I've looked. The condenser fan seems to reliably turn on and off when I turn on (or turn off) the a/c. The radiator fan does not always kick on, but after a hot commute, I've observed it to be on when I get home. The only time I've seen it off is when I've checked it to observe how the fans respond when cool.

Isn't it a closed system though for the a/c? And if the radiator fan stops working while I am in traffic, shouldn't I see the motor temp gauge start going up? I mean earlier this week, I was averaging about 5 mph in 95 degree heat (probably higher on the 4 lane highway) for a good 15 minutes where I had no a/c. I was watching the temp gauge because I was expecting something to happen, but nothing ever did. Would I need to idle longer than that to see anything on the temp gauge?

gearbox

iTrader: (95)

well you still have one fan on to cool the motor. its just the wrong one but it still blows air to the radiator too. one fan is enough to keep the car from overheating but not enough to cool the condensor. with the a/c on, both fans should be going regardless of engine temp.

JackedByJack

imo sounds like the compressor cut out on you. when my compressor died it still sucked power from my engine but only blew hot air.

BurtReynolds

Well it hasn't been hot enough to recreate the problem recently, so I guess I'll have to wait until it gets into the 90's again and see what happens. Then when it kicks over to hot air, find a place to pull over and try and see what is amiss. I was thinking it either has to be the fan shutting down or the thermal protector overreacting and opening the circuit on the compressor. I don't feel like the compressor itself is busted, or else it would probably shut down more often.

BurtReynolds

Update: It was a sustained 100 degrees or so yesterday, and the a/c went warm when it normally does in traffic. This time, it didn't come back though, so I was able to pull off in a parking lot while it was blowing warm air.

The only thing I noticed was that the radiator fan was not constantly on. In fact, it was fairly consistently intermittent. It would run for 20 seconds, rest for 1 minute, and then run for 20 seconds again. Only once I had it in the garage for about 5 minutes did it start running for longer than the 20 seconds. By that time sitting in the garage, the a/c was cold again as well.

Yet again though, I'll mention the temp gauge didn't move at all yesterday or ever, and the engine compartment was actually cooler than it was the day before. The day before, I popped the hood when I got home (the a/c was cool again by then) and it was hot in there. Pulling up the hood was hot to the touch, as well as putting up the hood prop. I didn't feel like I needed gloves yesterday just to pop the hood.

Is there some sort of overheat shutoff for the radiator fan motor? You would think that would be designed to run no matter what the temperature is, seeing the whole point is to cool the car. When the car is cool in the garage, the radiator fan turns on and runs fine.

Any ideas as to where to look for a fault with this fan would be appreciated.

TOPGUNN8309

I'd check the radiator coolant and make sure it's full. The vehicle dosen't have to overheat to be a little low on coolant, but it will affect the way your a/c works at an idle. When the vehicle is moving so is the coolant. Also you could be low on freon as well. Either way they are somewhat easy check's. Just an Idea, good luck and I hope it's one of these 2 things.

zuzzy

I had the same problem. It turned out to be a lose ground wire for the radiator fan. Once i found the lose wire and tightened it up problem solved.