A/C loses cool when not moving

[carbonejim]

Hi, My 2001 Eddie Bauer (111,000 miles) gets angry when she's not moving. As soon as I stop at a stoplight for 5 seconds or get stuck in bumper to bumper traffic the A/C loses it's cool. The system doesn't get cold if it's been parked in the sun all day until I put some highway miles on it. When I stop traveling so fast I do notice the air has increased in humidity. I've had a new drier, compressor, evaporator and accumulator installed. Some by CarX last year and now I'm working with the Ford Dealer.

I've hosed off the condensor to try to clear any bugs and cottonwood that may have been trapped there. It appears to be clear of obstruction. After I hose it down the air does get noticably cooler.

The radiator fan is blowing hard as it should.

The air was ice cold before one afternoon when it went HOT. The result was replacement of the evaporator. The air temp has not been ice cold again. The issues described have been happening since that repair.

I am thinking that the A/C system is no longer leaking. Is the condensor not cooling the fluid enough? I see a lot of posts about the orafice tube, but it seems like this is working because of cold air at high speeds. Why is hosing off the radiator/condensor helping? I need some ideas to present to the Ford Dealer mechanic or ideas that I can do myself.

The mecahnic was scrathing his head the last time we talked. I don't know the numbers on the system, but assume they were okay or the mechanic would see a problem.

My thought is the cooling system needs some help because it seems to get hotter than when she was younger. Could a radiator flush, tstat or water pump be help with some of these issues?

Help is very much appreaciated (wife wants to replace my Explorer - no way!)

-Jim

 

[Turdle]

It sounds like an air flow problem to me--

Maybe the fan clutch is slipping a bit.

Since the air flows over the condensor, then to the radiator-i wouldn't think the radiator has anything to do with it-

flushing couldn't hurt though--I'd give it a shot for sure.

You might check between the condensor and radiator for air blockage-debris-bugs leaves-cottonwood stuff-

 

[carbonejim]

Fan Clutch Check

I'll check the fan clutch after work and post back. Thanks for the idea. Pretty sure that their are no obstructions but I will check again. If that is working okay, I'll flush the radiator. I'm 99% sure that CarX simply drained and refilled my coolent instead of an actual flush.

-Jim


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HunterDan posted this on checking the fan clutch:

http://www.explorerforum.com/forums/showthread.php?t=189702&highlight=fan+clutch

To check the fan clutch, first with a cool motor, the fan should spin relatively freely, some resistance, but should spin, when the motor and radiator are hot, turn the vehicle off and the fan should be harder to turn than when it was cold. If your fan does not turn by hand when cold, and if it turns by hand when hot, there is a problem with the clutch. I have not seen many of these fail, but it does happen. It was about 95 with high humidity here in Central PA, my truck was a dog in stop and go traffic, A/C was on full blast, and fan was constantly engaged. I found this website that gives a pretty good explanation of a fan clutch, how it works and failure signs http://www.haydenauto.com/installati...tutorial-1.htm

HTH
Dan

 

[Rottie]

I'm almost wondering if it would be worth rechecking for a leak. Maybe a new leak has formed during all of the new component installations. My old Vic had the same problem. A recharge would temporarily fix the problem, then it would slowly start to lose it's cool - until you were on the highway for a little while. Does your A/C clutch cycle quickly like it could be low on freon? I think I would take it to a new shop and just ask for a leak check. That should be relatively cheap..

 

[cucumber1949]

For what it's worth, here is what happened to me last week. '97 Explorer SOHC 4.0.

On my way to lunch, a/c was working very well. After lunch, no a/c at all. The difference was night and day. About 30 minutes between the two. Thought I had developed a leak. Compressor clutch would not engage at all. Turned out it was the a/c low pressure sensor switch. An honest mechanic removed the harness plug on the switch, jumpered it and the clutch engaged immediately and cold air was back again. The part was $12 at NAPA and you can easily test & replace this yourself.

 

[carbonejim]

Update: The fan turns with very slight resistance when the engine is cold or hot. No difference as far as I can tell.

Question: How quickly would the cold air turn warm because of not enough air flowing past the condenser? The cold air turns warm and humid in about 3-5 seconds. I thought that was really quick.

More observations: If I'm sitting idle and I rev the engine to about 2000 RPM's, cold air begins to flow again. Could my fan not be turning fast enough at idle? Is this a fan clutch issue?

Yesterday a cloud puffed out of the vents for just a second. It appeared to be a puff of moisture. I had to laugh, but my wife didn't think it was so funny If I put my A/C on Auto at about 75 degrees, after the car cools down I hear a hissing sound through the vents. Sounds like something is draining?

My A/C clutch (compressor right?) is not short cycling. It engages as soon as I flip on my A/C.

 

[aldive]

As Jon pointed out earlier in the thread, it looks like an air flow problem. I would look further into the fan.

Good luck ....