Hey all,

I had a quick question for everyone. My 07 expy has been great for the first 25k miles, but as of about a month ago it started acting strange at idle.

The first thing is that I usually pre-cool the car as it is pretty hot here in Houston and I like to get the car cool before putting the kids in their seats. I do this by starting the car and setting the A/C to auto with a temp in the 70ish range. This has always worked in the past and after 5 minutes or so the car is comfortable. However, in the recent month or so it doesn't cool at all. In fact, it just blows humid hot air. Once I hit the highway I can hear the fan whirring way up and the truck cools off and runs normal, but if I sit at idle for a minute or 2 it starts blowing hot humid air again?

The second thing (and I think it's related) is that every minute or so at idle, with the car in "Drive", the vehicle lurches and the idle drops real low for a second. The first time it happened, I thought I was rear-ended. Interestingly, when this "lurch" happens, the A/C begins to blow cold for a few seconds before returning to hot and humid.

This can't be normal right? I've got a 97 expy as well and a TransAm and both cool just fine at idle right now.

Has this happened to anyone else before? If so, what was the culprit?

I'm going to take it to the dealer in the next day or 2, but would like to give them an idea as to what to look for.

Thanks!

Russell

 

No, sounds like something is bad. A/C compressor? I do know these trucks don't cool well at idle anyway, buy they shouldn't' just blow humid air. That sounds like the compressor is turning off completely.

 

Yeah,

That's exactly what it feels like. The air gets instantly hot and humid. I've been searching and trying to find info but haven't read anything about the A/C blowing hot air at idle. There have been a number of complaints about poor performance at idle, but at least it was cooling. This truck seems to just be blowing hot outside air into the cab.

 

Take it in. See what they find.

 

My magic 8-ball tells me that you're compressor is probably smoked and there may also be a leak in the system. Low pressure will cause the loss of cold air and the surging could be from a compressor clutch that is locking up when it trys to engage. If the compressor shaft seals have gone bad, I would imagine that the refridgerent leaking past the seals could very well be causing both issues. That would be the cause of the leak making the system blow warm air and the refridgerent may very well have damaged the friction clutch causing it to stick.

The only other thing I can think of may be a bad low-pressure switch. If the switch is acting up, it could be telling the compressor to turn on and off at the wrong times.

Whatever it is, I hope you get it worked out soon. Let us know what they found when you bring it in.

 

I'm also in TX - Dallas area. The A/C on my 2007 has been problamatic since new, and most of the components in my A/C system were replaced in my first 6 months of ownership. The system worked adequately (no better) up until the 105 degree summer temps came back. It always seemed to me that the compressor was turning on and off repeatedly. I took it to my new dealer here (Rodeo Ford) expecting to be told that the system was doing as well as it could given the exterior temps and to shut up and deal with it.

My experience was quite different. They hooked the HVAC control unit up to a computer and determined that it was faulty. They were able to get a replacement part the same day. I even got the 2009 control unit with the chrome circles on it! A/C works better than it ever has. Why Rodeo Ford was the first dealer to figure this out, I have no idea. But they did. One note: the cooling is definitely worse at idle, but it does function. Your problem sounds to me like the clutch that engages the compressor failing. Not a difficult fixx, but I hope you are still under warrantee.

Find a good dealer - and shop around for one of you have to.

 

Good to hear you got it taken care of. And yes, the cooling at idle stinks. I think this design was to save gas.

 

Well,

I suck at following up I did take it to the dealer last year and they checked everything out and said it was okay. They said they didn't do anything to it, but the truck never had the problem again, until yesterday.

Outside temps hit upper 80's in Houston and the truck is back to it's old tricks of not blowing cold air at idle (even after being on the highway). It was blowing stuffy air. I don't know that I'd say it wasn't conditioned at all, but it was definitely not cold air. The truck was NOT lurching at idle though. The radiator fan did spin way up high when we pulled onto the highway for about 30 seconds or so and then finally settled down.

This can't be normal behavior? When you guys say it doesn't cool well at idle, any relative amount? Would you say it blows cold air, but not ice cold? Or would you say it blows cool air, or lukewarm air? I'm trying to get an idea on expected performance. As I mentioned, the truck used to blow quite cool air at idle for the first 25k miles, but now it blows lukewarm air at idle.

 

Get a infared thermometer and measure the temps when it's blowing at idle. Compare that to the air while driving. Shouldn't be more than a few degrees diff.

 

The symptoms you describe points to an airflow issue over the condenser. The main culprit would be the fan clutch. The clutch can be vary weak at idle and still make noise at speed, it also may not effect the engine temperature.
To see if it is the clutch (or the radiator/condenser clogged with dirt and debris) spray water over the radiator while monitoring the outlet temperature. If the air from the vents gets cool or cold, you have a weak fan clutch or debris between the rad and condenser.

The lurching you were feeling was due to excessive head (high side) pressure in the AC system caused by your airflow issue.. There is a switch that disables the compressor at ~400psi to keep it from self destructing. You were feeling the compressor re engage when the switch closed again at about 250-300psi.

 

That is great info guys! Berry, the temp is easily 10 or more degrees different between idle and driving. I'll get an infrared thermometer just to make sure. Next time it does it I will try to get the hose out and spray the radiator to see if the temps drop.

I'll also check to see if there's any debris blocking the radiator. I don't think there is, but it's worth a check.

 

What year did Ford start using E-fans in the Expy's, or have they? At any rate, a truck this new should go back to the dealer.

 

I think this test proceedure works on all 6.0l diesel for the fan clutch. back probe the dark blue wire at the fan clutch connector and briefly jump to ground, fan should lock up and run at full speed, if not check red wire at connector and be sure it maintains full battery voltage, if it does then... bad fan clutch.. just went through this on 07 f250.

 

I had an old thread on this subject. I had problems a couple of times in 2007 & 2008, but not in 2009. There would be times at idle that there was no cold A/C and it was blowing hot. AZ gets extreme temperatures, so when the A/C cuts out, you really feel it. I had my EXPY to the dealer a couple of time to try and duplicate it, but they never could so all it cost me was a lot of gas (idling) and my time.
I did have the computer flash done in 2008 or 2009 for the transmission problem, so I don't know if other updates (A/C perhaps) were done at the same time. Coming in to summer, I'm concerned if the problem will surface again, but now I'm out of factory warranty and would have to pay a deductible even for trouble shooting.

I'm sure I'll here from my wife the first time it happens again.

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