09 expedition AC Warm at idle, cool while driving.

[max78]

Temps are starting to climb here and we hit 100 degrees last week.

My first thought is a weak cooling fan but I'm not sure. I do not have any overheating issues or anything.

When I start it I can sometimes hear the fan but not every time.

When I turn the AC on I can hear the fan kick on a little. It sounds like maybe it's on low speed.

Is there a connector I can pull to force the fan to run locked up/full speed so I know for sure it's working as intended?

I'm thinking maybe the coolant sensor?

 

[stamp11127]

Plenty of threads on here about ac issues. First thing to check is the airflow through the condenser/radiator. Wash both with low pressure water to remove any dirt or sand.

After checking the wiring diagram, Ford in their infinite wisdom now controls the climate system with modules. Fan speed is now under control of the pcm.

After those are checked the next item is the system pressures at rest and at idle for the specific ambient temp they are checked at.

If the pressures are correct then it is time for a scan with a high end scanner.

 

[ExplorerTom]

Does a 2009 have a mechanical or electric fan?

If it has a mechanical fan, turning on the AC doesn’t turn it on like an electric fan. It will only engage as the clutch warms up from the additional heat transfer.

My 2000 was the same way: frosty AC while moving but warm and pathetic in traffic. I replaced the mechanical fan with electric fans. Now I have cold AC at idle. I replaced the fan for a different reason though.

 

[max78]

Does a 2009 have a mechanical or electric fan?

If it has a mechanical fan, turning on the AC doesn’t turn it on like an electric fan. It will only engage as the clutch warms up from the additional heat transfer.

My 2000 was the same way: frosty AC while moving but warm and pathetic in traffic. I replaced the mechanical fan with electric fans. Now I have cold AC at idle. I replaced the fan for a different reason though.

From what I understand it's a hybrid.

It's still a mechanical fan, but its electronically controlled. What I'm not sure of is how it works, is it still a viscous coupler that's prone to failing, or something else? To me it looks like is still a viscous coupler so that's why I was wondering if there was a way to force it "fully locked" or whatever.

 

[stamp11127]

https://www.rockauto.com/en/moreinf...np0vnyIfYEQBz8+IjsiQ8n7SoAg/lSzEDyYcpHXr35R8l

 

[Trainmaster]

Can these simple things get any more complicated?

 

[max78]

https://www.rockauto.com/en/moreinfo.php?pk=2420632&cc=1443966&jsn=447&_nck=ZExt1ysfqhqWnq+EvUNdS3Txyey60IDtnjPWF5UU9J0BWQv7pvqZbkEUk86+AYIh/8vGRbRbhjtQtS85kRvd+HcYs0ObZkk208yYfTJPAScs7B+swxljvxsZkyWhAHAbckZiCm3zfD8aYwyjD/4enxFKjYl/dmMlt0mKoRwger49GJEZ/etd/VJKCwFVmALYd8tnU7Lt8oQeqEZSt1ZsCLtLGaQoOQUZY8psfp6x5zFuSrCt9GFAkwnDyt1EjBDTN/O5UGoTQATE0qeVWuln3+GjwyWXMfGwC1pw0x/XtvY3oLcf8vgnp0vnyIfYEQBz8+IjsiQ8n7SoAg/lSzEDyYcpHXr35R8l

Well look at that, I should read the rockauto parts descriptions!

Its a electronic viscous fan clutch, and dont replace without a trouble code (ya right!)

#2 on the how to detect a faulty fan clutch is poor AC performance at idle / low engine speeds.

 

[ExplorerTom]

Huh. Apparently they figured out a way to make a simple fan clutch more difficult.

You don’t want it fully locked. You’ll sound like a 737 taxiing for takeoff. Everywhere you go.

 

[max78]

Huh. Apparently they figured out a way to make a simple fan clutch more difficult.

You don’t want it fully locked. You’ll sound like a 737 taxiing for takeoff. Everywhere you go.

I know that, I just want to test it so see if it will fully lock up, because if it wont then there is an issue and it should be replaced. Most vehicles I have been around with any kind of electronic fan control, if the PCM looses coolant sensor it runs the fan full speed / lock-up, and was just asking the question before I start trouble shooting, I have been away from the truck. I will try it and it will probably throw a CEL but I can reset that.

Sometimes the fluid leaks out or breaks down and you get less engagement as they age. That means slower fan speed, but it can be gradual and you will get issues like warm AC at idle.

I will wash the condenser, check the pressures, and have my father-in-law scan it and maybe see if there is a self test that be performed.

I had my Jeep clutch fan lock up and it was miserable!

 

[Trainmaster]

What does that electronic, goo-filled POS cost?

It's computer controlled. Don't assume this is a simple on/off arrangement. This is designed for efficiency, not cold air conditioning. Tread softly before throwing parts at this thing.

 

[max78]

What does that electronic, goo-filled POS cost?

It's computer controlled. Don't assume this is a simple on/off arrangement. This is designed for efficiency, not cold air conditioning. Tread softly before throwing parts at this thing.

About $180 for a good one, so too much to just toss parts at it.

That's an excellent point and I will be sure to keep that in mind. The other thing I would be curious about is if 5 star tuning can adjust the fan speeds for me if I get a tune from them being that its PCM controled. I should probably ask in their forum.

 

[Dustin Gebhardt]

2 weeks ago I installed 2 electric fans in front of the condenser (and P/S cooler and aux trans cooler). My idle AC has greatly improved at the cost of a bit more noise (but only if you are standing near the front of the car).

 

[max78]

So, a bit of an update.

We had a nice long vacation weekend down at the beach. The drive down there was comfortable, the drive back was mostly comfortable but I think I have confirmed my suspicions that the fan clutch is on the edge of useful.

I guess there was a big party down there so coming back we got to sit at the border for about an hour or so. . .

Driving there the AC was great and we had to turn it down even though it was 103 outside. We get to the border and after about 30 minutes of sitting there the AC starts to cool off. I can feel it slowly getting warmer, and warmer, and warmer. . . we are 3 cars away from the checkpoint and it feels like I turned on the heater, the truck is slightly overheating, and I'm sure the pressures were out of control in the AC system because it would cycle off immediately. After passing the checkpoint the whole truck was an absolute dog from overheating but after a couple minutes of driving the coolant temp and AC were nice and cool again.

If someone has some spare time I would very much appreciate a video of the radiator fan noise with AC on in a hot climate. . .

I plan to make a video of before and After because there is no check engine light, and there are no codes.

Before I go out and replace the clutch fan, what

In other news, going down we averaged 15mpg loaded with a crap ton of stuff and 7 people. Coming back we averaged 16.5mpg with the same load and people. For the driving conditions I'm pretty happy with that!

2 weeks ago I installed 2 electric fans in front of the condenser (and P/S cooler and aux trans cooler). My idle AC has greatly improved at the cost of a bit more noise (but only if you are standing near the front of the car).

How did you go about wiring this up? What did you use to trigger the fans is more of what I'm asking. Trigger off the AC, or cooling fan?

 

[stamp11127]

Here is how we test the fan clutch on semi's. I do not recommend using your hand as shown. A newspaper or magazine is better - you avoid beating your fingers. You only want to slow down the fan slightly - not jam something into the radiator.

 

[max78]

2 weeks ago I installed 2 electric fans in front of the condenser (and P/S cooler and aux trans cooler). My idle AC has greatly improved at the cost of a bit more noise (but only if you are standing near the front of the car).

Here is how we test the fan clutch on semi's. I do not recommend using your hand as shown. A newspaper or magazine is better - you avoid beating your fingers. You only want to slow down the fan slightly - not jam something into the radiator.

I saw that one, I tested my fan clutch with it off and cool. I tried to spin it by hand and it wouldn't even spin a half revolution. I'm going to get it warm and try it again. I will borrow my father in laws scanner and see if there is a self test that be performed before I start shoving stuff into the fan.

The other thing I noticed is it seems to be almost intermittent. When we were sitting there overheating, I would slightly raise the RPM and you could hear the fan roar for a second and then it would go quiet. . . I bring it back down to idle for a sec and do it again, same result. The vehicle was overheating and the AC pressure were so high that it would not kick the compressor back on, so I'm sure one of the conditions commanding 100% fan were met, so I find it odd that it didnt stay 100% locked up as the RPM climbed.

I might stuff some cardboard in there later on when I have done everything else.

 

[Dustin Gebhardt]

2 weeks ago I installed 2 electric fans in front of the condenser (and P/S cooler and aux trans cooler). My idle AC has greatly improved at the cost of a bit more noise (but only if you are standing near the front of the car).

To further update my situation in the hope that it helps somebody else out:

1. Last year, after noticing poor AC performance, I discovered that the compressor was prematurely cycling on/off. Using my multimeter and comparing it to results I found online, I discovered that the temperature sensor in the evaporator box (behind the glove box) was malfunctioning. I used a basic 1/4W resistor to make the system think that the air temperature in the evaporator box was warmer. I think I settled on a 133k-ohm unit. This caused the compressor to cycle on longer before cutting out. Unfortunately, during long drives in cool weather, the evaporator will occasionally freeze up. I then turn off the A/C for a mile or two and then turn it back on. I'm still experimenting with higher-value resistors to find the right resistance in parallel to the built-in temperature sensor.

2. Even after installing the e-fans (see my previous post), idle performance of the A/C was anemic. I hooked up my gauges and discovered that I was tripping the low-pressure cut-off switch. Pressures on my high-side and low-side were lower than they should have been. I added a can of refrigerant to the system and the pressures came up to where they should be (just under 200psi and around 38psi at roughly 80'F ambient). It looks like I have a small leak somewhere. But I can live with that for now.

Currently, the interior temps will drop quickly after the car has been sitting in the parking lot all day. By the time I'm 5 miles into my commute home, my vent temperatures are typically around 35-40'F (sometimes lower) with an ambient temp in the high 80's. I still need to increase the resistor's ohms as I still occasionally have a frozen evaporator happen.

 

[TobyU]

Almost anytime the system cycles on and off it is a little low. Almost I say as some have high side cut offs too.

 

[max78]

So I tested my fan clutch last weekend, and honestly it seemed to test good. I would spin it and it would immediately stop. I warmed it up and it still seemed to be good. It was only about 98° outside so it never overheated or anything. I never did get my father-in-law over to see if there were any self tests that could have been run.

I broke down and purchased a Motorcraft unit anyways. I think it might be an intermittent issue rather than a consistent one and its my wife's vehicle she totes the kids around in so I don't want to wait till there is an issue. I suspect that its not an issue with the viscous coupler portion of the unit and more of an electrical or mechanical actuation issue.

I installed the new unit yesterday, and the amount of torque that was required to turn both of the viscous couplers while disconnected was identical. However after getting the new unit installed and started the vehicle for the first time the new unit pulls significantly more air.

I took it for a short drive and overall it seems to be pulling quite a bit more air, but that could just be that the computer hasn't adjusted itself for the new unit yet. This is all assumptions based on how audiable the fan noise is, the old fan clutch was always silent, the new one has a roar to it.

I will drive it for a couple days and we will see if there is an improvement.

 

[max78]

So, I fixed it. . .

Had my father-in-law come over and check the pressures with his gauges. He said it was a little over filled so he recovered some.

It didn't seem to make much difference and his gauges were well used so I rented some gauges and we checked again.

At idle low side was 80psi, high side 350psi.

We recovered refrigerate until it was 55 on the low side, 315psi high side.

The truck now blows cold at idle in 110degree heat.

 

[stamp11127]

To hot for my old azz to work in those temps.

If you want to play around you can recover/recharge to 90% of listed capacity and see how much the pressures drop for the 110 ambient. If the evap drops below freezing you should have enough latent heat in the cabin to keep it from freezing up.
Here in West Georgia, we have had the students run evaps at 10 degrees at 90+ ambient high humidity w/o freezing up. Low side pressure was @25psi, high @225. These were just above the low pressure safety switch threshold.