AC whooows!

[mike nadeau]

How is your ac?
I'm here in Phoenix and mine sucks! After new, condesor, expansion valves, compressor seems fine, and the switch to a mark vIII electric fan still only seeing 50's and when it gets into the 112 plus might 70's especially when sotting in traffic. I even had 2 electric pushers ontop of the mark vIII fan at 1 point.

 

[stamp11127]

Hook a good set of gauges up and read the pressures. That will tell you what the evap and condenser temps are.
Evaporator clean?
Blend door working correctly?
How much oil is in the system?

 

[mike nadeau]

Condensor is barely a year old. No bugs out here.
I had a mechanic buddy help me with the plugs a while back and while I was at it i replaced the low side schrade, which was leaking. So he evacuated and filled the system. He said the pressures looked fine. Well oil I have never pulled the compressor but when I replaced the condensor combination manifold hose and the expansion valves I added I belive 2oz. I figures as much with the leaks that had occurred.

 

[Bedrck47]

As stamp suggests GET a good set of gauges and read the pressures Then post those readings.

Your post states about work done a while back and a year ago. You need to find out if anything has changed since "a while back and a year ago"

Post the readings it will help others to better able to help you.

 

[mike nadeau]

I will do that but give you the history. 1 year ago I finally decided to start investigating the ac since we had just moved to the Phoenix area And summer was coming. I finally found that the fan clutch had never really worked the way it should and I wasn't willing to pay for a new motorcraft clutch at that point and started looking at an efan replacement. I found a mark viii fan and went with it hooked to a starter solenoid hooked to a temp relay. That was an improvement but not where it should be. So I then replaced the manifold hose, condensor and front and rear expansion valves. While doing this I never saw any metal shavings in the system. I then vacced and recharged the system. It was better but not cold while sitting idle. 8 months later, 2 months ago my mechanic buddy helped me and thats when it wad hooked to s good set of gauges and the schrader valve was replaced. No leaks since then.
Yesterday on the freeway with 112 degreees outside I saw 47 degrees at the vent. Once I was moving but when traffic stops it goes up to the 60' sometimes 70's. If I have to run a couple miles on side streets it nevere really cools down.

 

[mike nadeau]

At 80 degrees on start non cylce I see 40/125. When it cycles I get 34/154. This is my high end HF gauge set!
But as I sit here and watch right before the compressor cycles off my low side starts to drop. So Im thinking the compressor is starting to crap out.

 

[stamp11127]

This is where knowing the exact quantities of refrigerant and oil in the system is important.
If the correct amounts are in then the high side is low and the compressor may be on the way out or the system charge is low. If they are not correct then go back to square one. Recover the system and note the amount of oil removed. Recharge with the correct amounts of refrig and oil then read the pressures after running 10-15 minutes. Then increase airflow through the condenser and see if the nigh side pressure drops.
You want the low side pressure to be a few degrees above freezing at idle. I shoot for 35-37. A good gauge set will have a temp scale on the gauge face also.

 

[mike nadeau]

Then again 190k on the original compressor.

 

[docraymund]

It's usually a compressor problem. Replace it with a new unit and with your efan, you'll be cool this summer.

 

[stamp11127]

When checking pressures you need to let the system stabilize while running. I usually let it run - 10-15 minutes then take the readings.

Your pressures are still low on the high side. As the refrig level increases you will see a faster change on the high side compared to the low side.

Add 2oz of refrig, let it stabilize and check the pressures again. You want to see if the high side increases.

Our students are learning ac now. Shop temp is @78 degrees, pressures are 34/160 to 37/175. Part of their training is to undercharge a system, take pressure & temp readings then add 2oz of refrig take readings again. Keep adding 2oz until they are overcharged and compare readings.

How is the airflow through the vents? Nice and strong on high?

 

[mike nadeau]

Yes the airflow thru the vents is very strong. The evaporaters (front and rear) do not seem to be clogged in any manner. Not to be rude but I do not like to just add. In my mind my system takes 62oz of freon. So with 62oz the system should operate optimally. I do not have an evacuation system and hate the fact that if I have a leak and find low readings I ultimately have to, best case scenario, find the leak have the system evacuated fix the part and then vac and recharge. Plus I don't get any credit for what was evacuated, in most cases. So by not knowing how much the system lost without an evacuation and just adfing 2oz's I do not want to tax the "worn compressor" anymore than necessary. I am not an ac person by any means by try to learn and do what I can.
I feel the dedign of the 06 expedition radiator and condensor is flawed. I have a single core radiator thus have a gap between the radiator and the condensor. I feel this gap causes a nuetral air flow condition.

 

[Big Brian]

AC service takes someone with knowledge and the proper tools especially when an unusual pops up.

I would take it to a shop that specializes in AC service and have them fix it once and for all

other than that its all guess work

 

[1955moose]

One of the symptoms of a failing a/c compressor is higher than normal cabin temperatures. If you have a full charge of r134 freon, and all the other components are functioning as they should, ie blending doors, air flow, etc. You've kind of narrowed it down to the compressor. They are a wearable item, and what the hell you've gone this far, spring another $400.00 or so and replace it. Your other option is take it to a reputable shop, and pay them. But they may take your money and still have the same issue. Like I've always told friends in the past, I'd rather take a shot at fixing something myself and be wrong, than paying some yahoo to do it. Like the others said, double check your pressures, you can buy or borrow a set of r134 guages, make sure your pressures are close to spec, if all checks out, take a stab at a new or reman compressor and new belt if it's worn. Keep us posted. Moose.


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[Big Brian]

One of the symptoms of a failing a/c compressor is higher than normal cabin temperatures. If you have a full charge of r134 freon, and all the other components are functioning as they should, ie blending doors, air flow, etc. You've kind of narrowed it down to the compressor. They are a wearable item, and what the hell you've gone this far, spring another $400.00 or so and replace it. Your other option is take it to a reputable shop, and pay them. But they may take your money and still have the same issue. Like I've always told friends in the past, I'd rather take a shot at fixing something myself and be wrong, than paying some yahoo to do it. Like the others said, double check your pressures, you can buy or borrow a set of r134 guages, make sure your pressures are close to spec, if all checks out, take a stab at a new or reman compressor and new belt if it's worn. Keep us posted. Moose.


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he will also need a vacuum pump to do this job properly

 

[1955moose]

That or pay a shop to vacuum it out, then reuse the freon removed.


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