Poor AC performance?

Bilin Technician Nevada Posted   Latest   Edited  
Resolved
HVAC
2002 Ford E-350 Econoline Club Wagon XLT 5.4L (L) 4-spd (4R100)

Hello everyone,

friend of mine brought me a 02 e350 passenger wagon with rear ac, complaint is ac not cold enough when the ambient is above 100-105F. van cant stay cool inside. So i took a look at it. and seems like once it gets to 105 the air just not very cold. if i drive it on the freeway i can get the vent down to about 50-55F. idle 65-70 usually, rear roof vent around 75F. He had someone replaced compressor, condenser, receiver drier, and orifice tube. I checked the condenser inlet vs outlet temp, they are about 25F difference. and evaporator inlet/oulet are about the same temperature, but the line just doesn't feel very cold. I drove the van for about 10 mins and checked pressure, at idle high is around 250, low side is 80-85??. which seems way too high. someone told me because this has two orifce/expansion valves so the low side will be higher than a front ac system. and he said because this van use the same compressor like all pickup/van with front ac only, so it cant keep up with the dual ac when the ambient is high​.​probably he's right, but im suspecting a possible stuck open rear expansion valve? so its flooding the low side? or maybe a weak compressor

any input would be appreciated 

Side note: all the parts he replaced are aftermarket ones as well. 

He also had an auxiliary electric fan added in front of the condenser

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Mark Engineer
Colorado
Mark
 

Bilin Great challenge. I agree with you, I’m not too keen on the high pressure readings you’re seeing on the low side. I heard of this happening: the tech installing the orifice tube was color blind and got the wrong color installed. Maybe you can recover the 134a and check orifice colors. I’ve also heard of too much PAG oil. We’ll all be anxious to learn what you find

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Bilin Technician
Nevada
Bilin
 

I’ll look into that, I didn’t even think about that Thank you

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Paul Mechanic
Illinois
Paul
 

At 105 degrees and you vent temps at idle 70-65? That's a 35-40 degree drop at idle which is textbook. Are the windows tinted yet? Does owner have a history of better performance with same ambient temp and now it's not achieving it? Almost sounds overcharged given gauge readings, but again, those vent temps aren't bad considering. Maybe check airflow over condenser and make sure all baffling is…

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Bilin Technician
Nevada
Bilin
 

Yeah after I came back from the freeway I can the vent temps was 65-70. Windows are lightly tinted. He didn’t tell me about any previous performance. And I did do a evac and recharge just to make sure it has the correct charge. And this has the updated style condenser which takes less refrigerants. So I have about half a pound less than the label capacity. I would think if air flow is the issue…

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Robert Diagnostician
California
Robert
 

When I have seen duel systems on hot days the low side does run higher than a single system but not 80-85PSI. I have seen 40-45 PSI and the cooling drops off quickly if goes much higher. Is the system contaminated with flush? Overcharged with oil? Wrong compressor? Are there different compressors for single or dual systems? Do you have a blockage in the condenser? A thermal camera can help…

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Bilin Technician
Nevada
Bilin
   

I don’t believe they flushed the system, they replaced the compressor due to an external failure. I did a evac and recharge 1st, and during the oil draining phase, no excessive amount of oil was drained so I don’t think the system is overcharged with oil.I was wondering about maybe it has a wrong compressor so did look up on all data and there’s only one compressor for this van. I didn’t check…

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Peter Engineer
Alabama
Peter
 

System overcharged? At a training session witnessed a similar situation that was corrected by filling with exactly what was specified in the manual. Just a thought.

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Bilin Technician
Nevada
Bilin
 

I did evac and recharge just make sure the system is properly charged. And this has the newer style condenser which take less refrigerant. Its half a pound less that the sticker says. Sorry I should mentioned that. Thanks

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Thomas Owner/Technician
Michigan
Thomas
 

There shouldn't be any difference in the compressors. They historically use a common part for all applications. If there have been parts changed that require a different amount of freon then what the factory sticker says i would recommend reclaiming and recharging again. When you charge it again use a thermometer in the vent. Slowly add freon and creep up on the estimated amount and fill until…

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Fred Owner/Technician
Virginia
Fred
 

- No one ever calibrates their scales. You could still be over charged. - chech the high side lube all the way from front to rear. Temp should not drop until it reaches rear orifice tube. You could have a pinched or partially blocked line. - Your Condenser may be partially stopped up and not performing well enough to cool the rear. - Check all areas in rear AC where it should be insulated or…

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Vincent Diagnostician
Nevada
Vincent
 

Hi good morning, it can be very frustrating here in vegas doing AC as I have for over thirty years, the symptoms you’re describing suggest that the evaporator is being heated from a broken blend door or most likely on your Ford the heater control valve is allowing hot coolant to flow during ac operation. during a cold start does the AC blow cold until the vehicle warms up and then the pressures…

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Bilin Technician
Nevada
Bilin
 

Thats a great suggestion, i will check that when i get back. I don't believe this van use those vacuum controlled heater control valves like they use in the pickups, but I will check. Thank you

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Rusty Owner/Technician
Massachusetts
Rusty
 

I can’t see how hot coolant flow through a heater core could cause his elevated low side pressures. Most vehicles nowadays flow coolant unrestricted through the core and control temp via a blend door.

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Stephen Technician
Tennessee
Stephen
 

I suggest taking the actual temperature of the liquid line near each expansion device and of the suction line near the outlet of each evaporator. The gauge pressures are important to know the saturation point of the refrigerant. The actual temperature of the line will indicate how the unit(evaporator or condenser) is functioning. A flir or K type temp probe is best. IR guns are picky about the…

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Mike Owner/Technician
Australia
Mike
 

I always carry a spray can of quick dry flat matt black paint so I don't have to worry about adjusting the Emissivity values.

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David Owner/Technician
Alberta
David
 

Your low side pressure bothers me a lot. 80psi makes me think of overcharge and you have too much liquid refrigerant coming through the evaporator. I would want to know the temperature of that line and verify it.

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Glenn Owner/Technician
Texas
Glenn
 

Hi Bilin, I question the aftermarket “smaller” condenser. Have you confirmed this from Ford? If it was aftermarket, I would not recommend them. The whole purpose of the condenser in any AC system is to remove heat from the refrigerant. Making it smaller reduces it's capacity, which is very critical on dual AC units. Also check the auxiliary fan that was added to make sure it is actually moving…

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Bilin Technician
Nevada
Bilin
   

i haven't confirmed that with ford, but our shop does a lot of ford pickups and cargo vans around that time period, and we always get OE stuff, and all the condensers we replaced comes with a new sticker, and a paper stating that this is a new updated verison condenser that increase the efficiency of the system and also reduce the amount of freon it takes. the old condenser on these vehicles…

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David Owner/Technician
Alberta
David
 

I just looked at what Ford shows with their performance charts for this vehicle in Mitchell. Seems your system is running close to the normally expected level. They show at 100F, duct temp of around 50F. You probably do need a better condenser or some way to cool the liquid lines (not easy for this one)

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Glen Owner/Technician
Illinois
Glen
   

80-85 low side pressure is to high from my experience. Is there good flow through the outside of the radiator and is all the radiator/condenser shielding in place? I think if you fix the problem with the rear vent temp the low pressure will follow.

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Glenn Owner/Technician
Texas
Glenn
 

Hi Glen, You brought up a good point I did not think about earlier. Bilin, I recommend choking off the heater hose to verify a blend door motor has not failed. These had electric blend door motors on the front (and rear cases, if equipped). Manual knobs are not a cable system on these. Often times, the nylon gears breaks inside the blend door motor with age and heat. I recommend only an OE…

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Bilin Technician
Nevada
Bilin
 

I know the front blend door is working i can switch from hot to cold, I did not test the rear one. today was too busy did not get a chance to work on this van, will report back when i get an update, Thank you

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Glenn Owner/Technician
Texas
Glenn
 

Hi Bilin, Just for testing purposes, I would still choke the heater hoses, to make sure there is not a door seal issue. This will take the heating system out of the trouble shooting equation if nothing changes. After reading you post again, it is technically impossible to see 85 psig at the low side gauge yet you are seeing 50-55 degrees at the front vent. Generally as a rule pressure a temp…

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Bilin Technician
Nevada
Bilin Update
   

Thank you for all the great suggestions. I finally got a chance to work on this van, I did check the auxiliary fan, it is blowing the correct direction, all the shielding for the condenser/radiator are in place, and i did chock off the heater hoses going to the front and rear heater cores, no change. and knowing the quality of some of the aftermarket parts, i decided to get all oe parts, so i…

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Robert Diagnostician
California
Robert
 

how much oil did you put in the system? If the refrigerant capacity is reduced, so would the oil.

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Bilin Technician
Nevada
Bilin
 

Compressor came with 7oz, I removed 2oz accord to the instruction that came with the compressor , so 5 oz total

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Glenn Owner/Technician
Texas
Glenn
   

Hi Bilin. This is starting to focus possibly on the fan not moving enough air across/ through the condenser. I have seen times where an auxiliary fan could actually hurt more than help due to the body of it creating air flow blockage. With the temps you are dealing with, a 50 degree difference at the vent is actually within a reasonable range. We are talking about a van. A van is a gigantic…

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Mark Engineer
Colorado
Mark
 

Glenn I like your thought process but wonder about the pressures. Early on we learned high side was 250 while low side was 85. If we weren’t moving enough air through the condenser I wonder if we would see high side at 350-425 psi. Your thoughts?

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Robert Diagnostician
California
Robert
 

You are probably correct about the high side pressures. Spraying a little water on the condenser at idle while monitoring the pressures and vent temp would help figure that out. I like Glenn's idea on the orifice tubes. The question is why is the pressure high on the low side. Is it because too much refrigerant is being released or that the compressor is not moving enough refrigerant at…

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Glenn Owner/Technician
Texas
Glenn
 

Hi Mark, Going off the physics/dynamics, I am still not understanding how the low side reads 85 psig, but the vent temps are lower. Pressures and temps are relevant (reflective of each other). If the vent temps were about 50-60 degrees, the gauge should have shown the same within 8-10 degrees of what the gauge shows. The initial posting numbers are not making sense to me currently. Is the…

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Mark Engineer
Colorado
Mark
 

Glenn Early on in this post/thread I commented/wondered about the wrong color orifice tube. But, you may have hit on the root cause. We all hope and ASSUME that the 30 lb container of 134a we buy is really 134a. What IF, you are right when you comment/ask: Is virgin refrigerant being used? Is the recovery/recycle machine possibly contaminated? For all of you out there with far more experience…

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Glenn Owner/Technician
Texas
Glenn
 

Hi Mark, In the past there have been rogue companies selling Propane and Butane as safe substitutes. That was a real bad issue when R-12 and R-22 were being phased out as I recall. There are still some safety videos warning people not to use that stuff. With the current R134a now being phased out, history is repeating itself. I am sure there will be all kinds of substitutes flooding the…

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Robert Diagnostician
California
Robert
 

That would not be too much oil. I would think about air flow, (fan clutch, missing air dams to force air across the condenser). you could try a different orifice tube and maybe an adjustable one. If you spray water on the condenser do your pressures and vent temp improve significantly? That can determine if more airflow could help.

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Glenn Owner/Technician
Texas
Glenn
 

Hi Bilin, Did you ever confirm the rear expansion valve in question? If it is bypassing, even partially, it will affect over all system performance. Usually the valves fail in a closed position, so old system debris in the valve may be a factor. Next thought is the oil has been over serviced, so there is excess oil trapped in the evaporators. Too much oil will prevent efficient expansion of…

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Bilin Technician
Nevada
Bilin Resolution
 

I did check the rear, didn’t make any difference when I choke the high side going to the rear. when i removed all the old parts i did not see any excessive amount of oil. spraying water did help bring the temp down a little bit, also the low side pressure. in the end we tried a smaller orifice tube that seems to do the tricks for now, and because the weather is starting to cool off, im not sure…

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