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Flushing system and after flush?

Puffer on Thu July 28, 2011 5:47 PM User is offlineView users profile

Year: 1992
Make: Ford
Model: F150 XLT
Engine Size: 5.0L
Refrigerant Type: R134a
Ambient Temp: 90dgs.
Pressure Low: 57psi.
Pressure High: 325psi.
Country of Origin: United States


I have alot of questions, so I'll try to keep this as simple as possible. First off I'm a DIY'er and trying to save as much money is possible by learning how to do things myself. I have a 92' Ford F150 XLT that I'm planning on keeping for awhile and have fixed it up. The a/c has been changed over to R134a. I've read people talking about A6 and R4 compressors. I'm not sure which I have. I'm having a problem with it not cooling below 70dgs. I had the system evacuate, then I vacuumed it and checked it for leaks. When I vacuumed it there was still alittle pressure in it and I sucked out about 3oz. of oil. I took the compressor of and added the oil back to the system and recharged it with 40oz. of R134a. It still won't cool below 70. My thoughts are that it may have too much oil in it. My questions are do I have to take everything out to flush each separate component? I've already ordered a new accumulator. Where do I get an adjustable orifice tube? They're suppose to produce colder air?(notice the question mark), Once I get flushed and back together do I use PAG or Ester oil? and what viscosity 46, 100, 150? Also I've read about ES-12a being colder. What are your thoughts?

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92 Ford F150XLT

robs on Thu July 28, 2011 6:16 PM User is offlineView users profile

Well first of all, was the condenser upgraded to a parallel flow design when the conversion was done? That could be one of your issues with the system as to why its not cooling well. If the condenser is the stock tube and fin, I would recommend changing it back to the original design or upgrade to a parallel flow for a proper 134a conversion. A6 and R4 compressor are GM compressor, you either have a Sanden (20-10192) or a FS10 (20-10583) design on your vehicle.

Puffer on Thu July 28, 2011 7:37 PM User is offlineView users profile

I do know That FS10 is on the label.

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92 Ford F150XLT

robs on Thu July 28, 2011 7:49 PM User is offlineView users profile

Well there you go Puffman you have an FS10 compressor. You need to figure out what type of condenser you have and also decide what refrigerant you want to use. I would recommend only pure R12 or 134a with whatever decision you go with. A lot of manufactures will void warranties when using alternative refrigerants.

Puffer on Thu July 28, 2011 8:12 PM User is offlineView users profile

R134a is definitely what I want to use. How do I figure out what condenser I have? and Is the compressor the factory one or was it changed when the change over was done?

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92 Ford F150XLT

Puffer on Thu July 28, 2011 8:44 PM User is offlineView users profile

I forgot about the ES-12a. Are you or anyone else out there familiar with this refrigerant?

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92 Ford F150XLT

bohica2xo on Thu July 28, 2011 9:10 PM User is offline

Forget about ES12, it is basically propane & snake oil.

You have an OEM system with an FS10 compressor. Take a look at the picture below, and tell us what the condensor looks like:



Your pressures look high. Several things can cause this. Flushing the system is a good place to start, but first let's identify the condensor.

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.

Puffer on Fri July 29, 2011 2:50 PM User is offlineView users profile

It looks like I have a tube and fin condenser.

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92 Ford F150XLT

bohica2xo on Sat July 30, 2011 7:32 PM User is offline

Ok, you have the tube & fin unit. Those do not convert well, but they can be flushed.

The current replacement for that model year is a Serpentine. It is a better unit, but it can't be flushed easily. If you move foreward to the 1994 model year, the condensor is a 6mm design, more like a parallel flow unit. Ford swapped the F150 to 134a in the middle of the 1993 model year.

The best answer would be to fit the 1994 condensor.

The absolute minimum repair at this point would be to flush the evaporator and condensor back to bare metal. Flush the compressor with fresh oil. Blow the excess oil from the hoses. Replace the orifice tube with a standard blue ford tube. Replace the accumulator.

Replace the fan clutch with a heavy duty unit, and make sure the fan shroud is in place. Make sure no air bypasses the condensor on the way to the radiator.

Adjust the cycling switch down to 21 psi. Add the correct oil charge, and evacuate.

Charge 90% of the r12 charge, and monitor the pressures. Don't be surprised if the high side runs 3x ambient temperature.

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.

newton5 on Sun July 31, 2011 12:56 AM User is offlineView users profile

Bohica,
Have you seen piccolo style or PF condensers available aftermarket for Ford Trucks of this vintage?

I ask because of a discussion on another forum specific to Ford trucks. The poster assumed he had a PF condenser in his early 90s, converted R12, truck that was a new aftermarket part for his truck.
I suspect maybe it was a piccolo style condenser, but I don't know for sure.

His assumption was based on the very diagram that you posted here. His new condenser construction matched the PF illustration, unlike his original condenser which was a serpentine style.

A quick internet search turned up pics of some aftermarket condensers for 8x-93 Ford trucks that had "cross flow" construction as opposed to one continuous path like OEM serpentine units. None claimed to be "better than original" or anything like that. They just showed up as replacement parts.

I'm not sure what to make of that. Any thoughts?



newton5 on Sun July 31, 2011 1:02 AM User is offlineView users profile

Oops. Double post.





Edited: Sun July 31, 2011 at 11:36 AM by newton5

bohica2xo on Sun July 31, 2011 2:36 AM User is offline

Newton:

From our very own sponsor...

1994 Condensor

1993 Condensor

I realize the core is a couple inches wider on the 94, but I believe there is room in the radiator support on the 92. Even the serpentine is somewhat better than the tube & fin. If your guy on the other forum put the 94 condensor in, ask him if he trimmed anything to get 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.

Puffer on Sun July 31, 2011 7:54 AM User is offlineView users profile

OK Bohica, I think I can handle the minimum. Once I get to replacing the oil how do I find out how much oil the system is suppose to hold?

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92 Ford F150XLT

Puffer on Sun July 31, 2011 8:39 AM User is offlineView users profile

I forget to add. What type of oil do I use? The manufacturer of my compressor said to use ester100. What's the diff between ester100 and pag100. Also my mechanic friend told me to use pag46????
2. Why do I need to replace the fan clutch?
3. You said change the switch to 21psi. I read that I should turn it 1/8 of a turn CCW but if the compressor runs all the time like it does, how will I know when I'm at 21psi.?

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92 Ford F150XLT

newton5 on Sun July 31, 2011 11:52 AM User is offlineView users profile

Quote
Originally posted by: bohica2xo
Newton:



From our very own sponsor...



1994 Condensor



1993 Condensor



I realize the core is a couple inches wider on the 94, but I believe there is room in the radiator support on the 92. Even the serpentine is somewhat better than the tube & fin. If your guy on the other forum put the 94 condensor in, ask him if he trimmed anything to get it in.



B.

No modification was mentioned and the lines also mated correctly.
I'm thinking that maybe some aftermarket mfgrs. are using the 6mm core for both pre and post 94 units. It would save them from having to stock 2 different cores for very similar applications. The only real difference is the size of one of the fittings, as far as I can see.

bohica2xo on Sun July 31, 2011 2:51 PM User is offline

Quote
Originally posted by: Puffer
I forget to add. What type of oil do I use? The manufacturer of my compressor said to use ester100. What's the diff between ester100 and pag100. Also my mechanic friend told me to use pag46????

2. Why do I need to replace the fan clutch?

3. You said change the switch to 21psi. I read that I should turn it 1/8 of a turn CCW but if the compressor runs all the time like it does, how will I know when I'm at 21psi.?


I agree with the compressor supplier, ester 100 oil LIKE THIS
Is this a new compressor?


The fan clutch is very important when you have a marginal condensor for a conversion. You need all the airflow you can get to hold pressures down. Fan clutches wear out, and since the vehicle does not overheat people assume they are still ok. Head pressures skyrocket, and A/C systems fail silently. Have you ever replaced the fan clutch on this vehicle?

When the system is actually cooling right, it will cycle. Set the cabin fan to the lowest speed, and increase the engine rpm to 1500. It should cycle off around 21 psi, and back on around 33 or higher. If it needs to be adjusted, pull the plug off & make a partial turn - then put the plug back on & watch the gauge.





-------------------------
"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.

Puffer on Sun July 31, 2011 6:39 PM User is offlineView users profile

I agree with the compressor supplier, ester 100 oil LIKE THIS

Is this a new compressor?





The fan clutch is very important when you have a marginal condenser for a conversion. You need all the airflow you can get to hold pressures down. Fan clutches wear out, and since the vehicle does not overheat people assume they are still ok. Head pressures skyrocket, and A/C systems fail silently. Have you ever replaced the fan clutch on this vehicle?



When the system is actually cooling right, it will cycle. Set the cabin fan to the lowest speed, and increase the engine rpm to 1500. It should cycle off around 21 psi, and back on around 33 or higher. If it needs to be adjusted, pull the plug off & make a partial turn - then put the plug back on & watch the gauge.



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I already have a bottle of pag100. Will that work? Whats the difference?

I know I may sound like an idiot, but I didn't realize the fan even had a clutch. I thought that the fan ran the whole time the engine was running. If I do have to get a new clutch, can you recommend a place to get one at a decent price? What do the usually run?

As far as the compressor goes, I've never replaced it. I don't know if it's the original or if it was put in when the system was changed over to 134a in 2004. It seems to be working fine though. I had it off and everything is clean inside. The clutch doesn't seem to be slipping. I think it may actually be too tight. You can see it trying to grab a little when the compressor clicks off.

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92 Ford F150XLT

bohica2xo on Sun July 31, 2011 7:12 PM User is offline

If the compressor is marked "ester", it was replaced sometime after 1994. stay with ester oil. PAG is not ester, and is very prone to moisture contamination. The BVA ester already has the dye added for UV leak detection, saves buying the dye as an extra.

The fan always turns, but at a reduced speed until needed. The clutch includes a viscous drive that "slips". As the clutch accumulates miles, the working fluid in the clutch thins out - and it moves less air. The second part of the clutch is a bimetallic spring that engages the clutch when things get hot. As the clutch wears out, it fails to reach full speed even when hot. Yours is probably well past worn out. Once you replace it you will know how bad it was the first time you start the engine.

Trucks with factory A/C had a 19 inch fan. Without A/C was an 18 inch fan. They used different clutches. Expect to pay 60 bucks or more for a quality clutch. Avoid the cheap clutches, they can crap out in months. A motorcraft clutch runs about 120 bucks for the 19 inch fan.

Your compressor clutch gap can be adjusted if it is too tight.

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.

Puffer on Mon August 01, 2011 10:44 AM User is offlineView users profile

I've looked all over the web and still can't get a definitive answer on how much oil to recharge the system. The closest I got was 2oz. for each component. I'm pretty sure that the compressor holds 8oz.

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92 Ford F150XLT

Puffer on Mon August 01, 2011 11:19 AM User is offlineView users profile

I just came across a chart that shows refrigerant and oil capacity for a/c systems. I don't know how accurate it is because, 1. It only shows 98'-04' models, and 2. It says 9oz. of oil and 33oz. of 134a when the sticker on my truck says 40oz.

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92 Ford F150XLT

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