Automotive Air Conditioning Information Forum (Archives)

jacob_coulter on Tue August 31, 2010 7:02 PM

Year: 2007
Make: Ford
Model: Expedition

I have a 2007 Ford Expedition that has poor performing AC. The first time I took it to a dealer (under warranty) because the air just wasn't that cold. They said they replaced the expansion valve. It did feel a bit colder (but not ice cold), but began to feel warmer once again. Other passengers also noticed it, even at the most max setting, recirculation on, and it's been running for a while, it gets a little warm. Not hot, but just not that cold. I took it in, and the dealer said everything was within spec. The car is still under warranty.

Here's my question. Does the AC on Fords just suck in general? I live in AZ, so I need good AC. The windows have a dark tint, and the car is white. I put a vent thermometer and at idle the temp gauge is around 55 degrees. I have an 11 year old Lexus ES300 that has AC that will blow ice cubes at you, I measure around 40 degrees, and it gets there nearly instantly. Seeing how there's a massive condensor with a large open grill with the Expedition, a V8 and large compressor, the Expedition should put the Lexus to shame, but it doesn't. The Lexus with the engine that's nearly half the size and has a grill opening of about 3 inches tall yet it blows the Ford out of the water.

Should I take the dealers word and just deal with an inferior AC system, or should I expect 40 degrees at the vents? I was thinking of maybe adding a pusher fan in front of the condensor, or maybe a heavier duty clutch fan? Hot water shut off valve? I'm willing to make some mods, but I really shouldn't have to, this was a $40k vehicle.

I'm definitely not happy with the Ford product. I'm more of a Ford guy, but a friend has a GM Tahoe, and it has a MUCH better AC system. What should do? (besides buy a Tahoe

Thanks for the help!

bohica2xo on Tue August 31, 2010 7:28 PM

How many miles on the expedition? Which engine? Rear A/C, or only the front?

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

jacob_coulter on Tue August 31, 2010 7:32 PM

About 36k miles, and it has rear Ac and also the cooled seat option (though I almost never use either of these, and not when I was measuring the vent temp.)

The engine is the 5.4L, it's a Limited with 4wd.

GM Tech on Tue August 31, 2010 8:47 PM

Do your idle testagin-- but this time mist th condenser with a garden hose....then see what vent temps are.. if this helps, you have an air flow through condenser problem.

-------------------------
The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

jacob_coulter on Tue August 31, 2010 8:56 PM

I can try the garden hose trick, but wouldn't that lower the temperature on any AC system since water is much better at absorbing heat than air?

Cussboy on Tue August 31, 2010 10:24 PM

Quote
Originally posted by: jacob_coulter
I can try the garden hose trick, but wouldn't that lower the temperature on any AC system since water is much better at absorbing heat than air?

No. The job of the condenser is to cool the hot refrigerant to a liquid, so it can expand/draw heat passing through the expansion device into the evaporator. So if misting the condenser helps significantly, then your condenser fan(s) are not doing their job(s).

bohica2xo on Tue August 31, 2010 11:55 PM

The 5.4 Expedition should have the computer controlled fan clutch, so any problem with fan output is something you can check with a scanner.

I don't have the book open right now, but that vehicle has either the FS20 piston compressor or a scroll. I can't recall which way the Expedition went that year. If the compressor has exposed crossbolts holding the body halves together, it is an FS20. If it is smooth on the one piece body with a flange on the front, it is a scroll.

The rear TXV is also electrical, and connected to the body computer. The front TXV should be a plain old mechanical H type block.

There is a lot of computer involved in that system, and a scan tool is a big help.

Let the vehicle idle with both A/C blowers on the highest setting, and the doors open. With the engine at operating temperature, idling with a full load on the ac for 5+ minutes should push the high side up far enough to call for 100% fan. Bumping the engine rpm up to 1200 or so should verify the fan request - it should roar. Let it idle again for a couple of minutes, and observe the vent thermometer. Raise the engine speed to 1500+ rpm, and listen to the fan. It should be roaring. Hold the 1500 rpm, and watch the vent temp. If you hold the 1500 for 5 minutes, you should hear the fan cycle or change speed. Check the vent temp after 5 minutes of 1500 rpm. Record the vent numbers and post them.



Poor service response on a Ford A/C with marginal output is not new to me. I had an Explorer with a crap scroll compressor that the dealer said was just fine. Drove me nuts because it was the wife's company car, and I was not supposed to wrench on it. The dealer would blow her off like she was a slow fifth grader when she took it in...

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

Edited: Tue August 31, 2010 at 11:57 PM by bohica2xo

jacob_coulter on Wed September 01, 2010 12:00 AM

Quote
Originally posted by: Cussboy
Quote
Originally posted by: jacob_coulter
I can try the garden hose trick, but wouldn't that lower the temperature on any AC system since water is much better at absorbing heat than air?



No. The job of the condenser is to cool the hot refrigerant to a liquid, so it can expand/draw heat passing through the expansion device into the evaporator. So if misting the condenser helps significantly, then your condenser fan(s) are not doing their job(s).


I guess it's a matter of how much it drops the temperature to keep an eye on in order to diagnose, but I would think it would be no different than testing an AC system if it was significantly colder outside. I'm guessing if it was 75 degrees outside instead of 105, my vent temperature would also drop significantly.

In the same way, if I start running cold water on a radiator, the engine's coolant temperature would drop dramatically, even if everything in the system was working properly.

Help a layman understand this, am I comparing apples to oranges here?

jacob_coulter on Wed September 01, 2010 12:04 AM

Quote
Originally posted by: bohica2xo
The 5.4 Expedition should have the computer controlled fan clutch, so any problem with fan output is something you can check with a scanner.



I don't have the book open right now, but that vehicle has either the FS20 piston compressor or a scroll. I can't recall which way the Expedition went that year. If the compressor has exposed crossbolts holding the body halves together, it is an FS20. If it is smooth on the one piece body with a flange on the front, it is a scroll.



The rear TXV is also electrical, and connected to the body computer. The front TXV should be a plain old mechanical H type block.



There is a lot of computer involved in that system, and a scan tool is a big help.



Let the vehicle idle with both A/C blowers on the highest setting, and the doors open. With the engine at operating temperature, idling with a full load on the ac for 5+ minutes should push the high side up far enough to call for 100% fan. Bumping the engine rpm up to 1200 or so should verify the fan request - it should roar. Let it idle again for a couple of minutes, and observe the vent thermometer. Raise the engine speed to 1500+ rpm, and listen to the fan. It should be roaring. Hold the 1500 rpm, and watch the vent temp. If you hold the 1500 for 5 minutes, you should hear the fan cycle or change speed. Check the vent temp after 5 minutes of 1500 rpm. Record the vent numbers and post them.







Poor service response on a Ford A/C with marginal output is not new to me. I had an Explorer with a crap scroll compressor that the dealer said was just fine. Drove me nuts because it was the wife's company car, and I was not supposed to wrench on it. The dealer would blow her off like she was a slow fifth grader when she took it in...



B.

I'll look into this, but I'm guessing it's going to be the same end result, Ford says it's just fine. They spent quite a bit of time diagnosing at my insistence, so I'm doubting something is technically"wrong".

Would you suggest any mods to overcome the poor AC and make it ice cold? I'm willing to spend some money if it makes a noticeable improvement, I plan on keeping this vehicle for a while.

jglanham on Wed September 01, 2010 1:06 AM

Quote
I put a vent thermometer and at idle the temp gauge is around 55 degrees.
Quote
I'm guessing if it was 75 degrees outside instead of 105, my vent temperature would also drop significantly.

Are you saying it is 105* ambient and you have vent temp of 55* at idle? That is a 50* drop from ambient at idle! What is vent temp when driving on the highway?


-------------------------
johnl

jacob_coulter on Wed September 01, 2010 1:14 AM

Quote
Originally posted by: jglanham
Quote
I put a vent thermometer and at idle the temp gauge is around 55 degrees.

Quote
I'm guessing if it was 75 degrees outside instead of 105, my vent temperature would also drop significantly.



Are you saying it is 105* ambient and you have vent temp of 55* at idle? That is a 50* drop from ambient at idle! What is vent temp when driving on the highway?


I was just using that temperature for the sake of an example.

On the same day and roughly the same time, I tested my Lexus and compared it to the Expedition, and the Lexus vent temperature was around 40 degrees vs the Ford that was around 55 deg. I'm just chalking it up to the Ford not having a great AC system.

I've owned cars in the past that were working properly, they just weren't that great in really hot climates like AZ. Usually though it was smaller, compact cars that had smaller compressors and condensors. I owned a Subaru and a Honda that just didn't do a great job of cooling.

I really think though that there's no excuse for a full size vehicle like an Expedition not being able to put out ice cold air.

bohica2xo on Wed September 01, 2010 1:38 AM

Jacob:

Vent temperature is not the whole story. Cooling "power" is best described by a mass of air at a temperature. For example 100 pounds of air a@ 40 f vs 300 pounds of air @ 50f. Sure the 40f air feels colder, but how much heat can each remove from the same sized space?

You may be short changing yourself if the Explorer system has enough nuts to pull both evaporators down to 50f at max blower. While it may not feel as cold from the vents as 40f air, a whole bunch of 50f air will pull that space down quickly.

You asked about system modifications for more cooling. As with anything computer controlled, it can be hacked. I wound up doing that with the Explorer, because there was an awful hysteresis in the compressor cycling. I could not do anything about the crappy compressor drive ratio, so I swapped out both ring & pinion sets to 4.56's... It all depends on how far you want to go.

Id the cooling complaint only at idle, or highway speeds as well?

I will be back at work tomorrow, and will look at the 07 Exp. a little closer for ya. Perhaps there is some low hanging fruit.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

jacob_coulter on Wed September 01, 2010 2:38 AM

Quote
Originally posted by: bohica2xo
Jacob:



Vent temperature is not the whole story. Cooling "power" is best described by a mass of air at a temperature. For example 100 pounds of air a@ 40 f vs 300 pounds of air @ 50f. Sure the 40f air feels colder, but how much heat can each remove from the same sized space?



You may be short changing yourself if the Explorer system has enough nuts to pull both evaporators down to 50f at max blower. While it may not feel as cold from the vents as 40f air, a whole bunch of 50f air will pull that space down quickly.



You asked about system modifications for more cooling. As with anything computer controlled, it can be hacked. I wound up doing that with the Explorer, because there was an awful hysteresis in the compressor cycling. I could not do anything about the crappy compressor drive ratio, so I swapped out both ring & pinion sets to 4.56's... It all depends on how far you want to go.



Id the cooling complaint only at idle, or highway speeds as well?



I will be back at work tomorrow, and will look at the 07 Exp. a little closer for ya. Perhaps there is some low hanging fruit.



B.

Thanks for the help, I really appreciate it. Let me know what you find out.

It's a good point about the volume of cool air, the only reason I was measuring the temperature in the first place was because it was uncomfortably warm. I'm not worried about the reading on the thermometer necessarily, I just want a nice cool car for the family. Other passengers have noticed, it's just not that cold on those really hot days.

Changing the ring and pinion sets is definitely further than I would like to go, especially since my shadetree skills are not comfortable with swapping gears, I'm guessing I would be looking at $800 minimum from a shop for parts and labor for that type of project. I'm guessing AC performance though was not the only reason for the swap

Something like wiring an auxilary pusher fan to come on when the compressor engages is more up my ally, I just want to make sure it makes a noticeable difference.

1stbscout on Wed September 01, 2010 8:40 AM

Yes you are correct.... water does conduct heat better than air. By running a garden hose over the condenser you will essentially make it into a water cooled heat exchanger and the high side temps will drop to those which are correct for the temperature of the water plus a slight amount for evaporation depending on temperature and humidity. Dropping the high side temps gives the system more "headroom" (if you will) therefore creating better cooling.

if you soak the condenser with a garden hose it will cause the system to cool better.... and yes that is any system.

The idea is not to soak it but to mist it with just enough water to help the heat transfer and cause some evaporative cooling. using a spray bottle will work much better than using a garden hose.

Personally I prefer to check temps into the condenser and out of it. Most of the time if the outlet temp is within 30* of ambient the condenser is being cooled as well as it can by the air flow over it's surface.

Checking the inlet temp gives me a better idea how well the compressor is working and whether or not it has problems. Expecting any air over heat exchanger to cool excessively high temps coming from the compressor is expecting too much.

In most respects you are heading down the right road. IF the system is properly charged you need more than just pressure readings in order to troubleshoot the system. The pressures in the system become secondary, without accurate temp readings it becomes a guessing game, just like without accurate pressure readings it is a guessing game. The two work hand in hand to determine whether or not the system is performing to its best.
I am out of time for this morning, need to go to work and fix a few more systems.

jacob_coulter on Wed September 01, 2010 12:20 PM

Also, would some sort of hot water cut off valve help cool the AC, something like this:

http://www.dieselsite.com/index.asp?PageAction=VIEWPROD&ProdID=473

I'm not sure if my AC system is set up the same way, but a lot of the diesel owners say it made a big difference.

bohica2xo on Wed September 01, 2010 3:36 PM

Jacob:

Just had a look at the 07 exp. for ya. It has an FS20 compressor. That fan clutch assembly is that same as the Super Duty's, and I doubt this is an airflow issue. Never had a problem with an SD, and the heat exchanger package is a nightmare - the condensor is behind the trans cooler, the intercooler, the steering cooler...

There are a couple of hacks that are simple enough, but first let's try to pinpoint the issues for you. You feel it should cool better, and the vent temp is higher than you want. You do not generally use the rear evaporator currently.

I need you to do a couple of simple tests for me, and we can get to the right part of the loop. Tonight, after sundown grab your vent thermometer and go for a drive. Speed is not important, as long as you can meet the rpm requirements.

1) Put the thermometer in the center vent, with all vents open.

2) Set both front & rear cabin fans to the highest speed. Run both A/C evaporators.

3) Drive 30 to 70 mph, or whatever will keep the engine rpm 1500 or higher
Record the vent temp when you start, and after the cabin cools down to a comfortable level. An approximate time for pulldown would be good too.

4) Shut the rear A/C down. Reduce the front cabin fan speed to the lowest setting.
Drive for a couple of minutes with the fan on low. Record the vent temp.

5) Idle for 5 minutes, fan still on low. Record the vent temp.

That's it. Just some vent temps under different conditions. Get back to me with that data, and we will know what direction to head.

B.


-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

douge on Wed September 01, 2010 4:25 PM

douge on Wed September 01, 2010 4:31 PM

First off, sorry for the empty post right above this.

Jacob
I was going to start a thread on this same subject. I have the same 07 expedition, 5.4, EL with rear air.

I too am very disappointed with this truck's AC performance. I live in Texas where we typically see 100+ temperatures.

I only wish I had vent temperatures as good as yours. My vent temps while driving only get to about 68 at best. Took it back to Ford three times so they could tell me everything is within spec. Now, warranty is out and I am stuck. Not a happy ford customer and getting rid of the truck is not an option.

Hope someone has some answers that will help us both.