lsr,

Your analogy of the r/d being a steak is a very good one.

Also, thanks for pointing out the facts about this particular compressor. I do a good bit of auto a/c work, but on a popular German make, not Ford trucks. Nothing beats specific knowledge of the breed.

 

Thanks Doc.
Scroll compressors are fairly new in automotive applications. Most Ford trucks since the mid-late 2000s and most later Hondas also use them. There are a few other applications too, but I'm not sure where.
One thing that they don't tolerate well is high outlet pressure. I see a lot of them with a hole blown in the compressor body. This usually happens when a cooling fan fails, or shortly after.

 

Last three questions before I dig into this thing on Sunday afternoon. I got a vacuum pump lined up, and just stopped by the dealership and picked up new o-rings for the condensor(2), accumulator(1), and orifice tube(3) hook ups. The compressor has new o-rings(2) on it. Walmart had the 134a (bottom shelf). I am pretty sure I have everything.

The motorcraft compressor has a replacement procedure sheet with it. In there it states that the compressor if fully charged with 7 oz of oil. The system holds 9 oz. If I drain all of the oil out of the compressor and I only get 5 oz out, should I calculate the other 2 oz into how much additional oil to add? Example: 5 oz out, put 4 back into the compressor, 1 oz in the new condensor, 1 oz in the evaporator, and 1 oz in the new accumulator, and figure there is already 2 oz stuck in the compressor. Or do I forget about the 2 oz and add 9 oz after I drain the compressor?

What is the best way to recharge the system. I think you need to run a jumper wire across the plug on the accumulator while the truck is running. Should/ can you fill while the truck isn't running? Should you shake the 134a can, hold it upside down, etc?

ISRX101-- what is a EMD E-8A

Thanks again for all the help, I am now confident it will go well.

 

It sounds like you have everything you need to assemble the system and you're correct on the oil.
However, I would drain the shipping oil, then toss it and add back the total amount of fresh oil w/UV dye from a sealed container.(3-4oz in the compressor, the rest in the accumulator and condenser).
PAG oil is very hygroscopic, it absorbs moisture like a sponge. I don't always trust how the shipping oil may have been handled previously.

Do you have a manifold gauge set and a can tap for your refrigerant cans?
Here's an evacuation/charging procedure:
Automotive AC Information Forum - ACKITS.COM

 

You had stated in an earlier post to drain the oil out and put new in, and I was planning on doing that since you know alot more about this than I do. I was just thinking what could happen, like only being able to drain out 5 oz of the 7 oz and what to do at that point on Sunday when I don't have anyone around to ask. I will try to drain all 7 out by turning the pump, but will it all come out? I don't know anything about the design of the pump. I wanted to ask before I did the wrong thing. I will calculate in the remaining oil into the total oil amount.

I do have a manifold gauge set, with all the correct fittings and hoses for a 134a system. It also has a tap for the 12 oz cans. Picking up the vacuum pump tonight. I printed out the filling instructions.

 

I expect that you can "drain" the compressor oil on these compressors as you do on most others. With the compressor out of the vehicle, turn the forward portion of the clutch, not the pullies, clockwise with the fittings down. Turn it until you get nothing but a few infrequent drips.

 

Oh, I missed this:

ISRX101-- what is a EMD E-8A

It's a Locomotive built by Electro Motive Division of General Motors.
I belong to a group that is restoring a 25 mile rail line in northern Ohio. The E-8 (LSRX-#101) is our primary loco for excursions. This particular one was built in 1950. Click on the link in my signature for pics, she's darn pretty.

As a truck guy you might appreciate this. It has 2 prime movers (motor-generator sets) each powered by a 12 cylinder, 2-stroke diesel engine. The model 567 engines produce 1100 horsepower each. The "567" designation, aside from being the model number, means 567 cubic inches of displacement per cylinder! Yep, 13,608 cubic inches.

 

When you didn't respond about it I thought it may be some top secret military jet, tank, etc. I will have to check out the pics.

I got the new condensor, accumulator, compressor, and orifise tube in the truck. I drained 6 of the 7 oz of oil out of the compressor, I split 8 oz of new oil in the compressor, accumulator, and condensor (calls for 9 oz). I vacuumed down the system and put 4, 12 oz cans of 134a in the system. Everything went really well, not a lot wasted. The only thing that was a little strange was the placement of the orifice tube. It didn't really slip into, or have a stop where it should go. I put it back in at about the same location it was in, as far as I can remember. It sort of felt like it was in right.

The system was cooling really well when I was adding and right after I got done charging the system. The pump was running for long cycles. The maximum pressure on the high side was around 250 psi (temp approx. 75). I was really happy with it and thought this was over with.

So I washed the truck and then took it for about a half hour drive. During that time it wasn't really cooling again. But I didn't have time last night to look at it. This morning I got the gauge set back on the truck. Temp about 65, and the stadic pressure was 77 psi. I started the truck and let it run for about 2 min while I was getting the RPM set to about 1500. I then turned the AC on MAX blower high, and opened the windows. The compressor was cycling 2 seconds on, 5 off. The pressure was going from 125 to 200 high side and 50 to 25 low side.

I think it is a little low on charge, but I wanted to check with you before I do anything and mess it up. There was another post on here with a chart of pressures that I was looking at. Does the truck have to warm up more? When I was charging it the truck was running for a while. I hope the orifice tube isn't in too far or not far enough. Something else wrong?

 

Your pressures sound just about right for 65 degrees. The high side is a bit high, actually. The rule of thumb is 2.5 times ambient temp on the high side.

4x 12oz cans is 48 ounces, minus a couple of ounces lost when changing cans . That should be really close. What does the under hood sticker say for the recommended charge?

 

I would think the charge would be close also. Like I said the whole job went really well, and the only think I would even be slightly concerned about would be the orifice tube. The air was working great in the garage while I was filling it. The pump was running for long periods of time the really putting out the cold, not cool, cold air. The sticker says 2.82 lbs of 134a.

I ran, tried to at least, run the ac on the way home from work. It was only slightly working. When I got home I hooked up the gauge set again to check it. High side 140 to 190, low side 50 to 20-25. Pump on for 1 to 1.5 seconds, off 2 to 3 seconds. Air temp 72-74.

From the chart I think the pressures look pretty good, but I don't really know much about this stuff. But the pump starting and stopping is where I think the problem is and it looks to be shutting off on low pressure. I do loose a certain amout of 134a every time I hook the guage up and take it off because of draining the hoses after the hookup. How much I don't know.

????

 

Your dessicant left the accumulator and was pushed through the compressor into the condenser at high pressure, where it is finally filtered by the orifice tube.

The Condenser is probably clogged too, that is the part that takes the heat away, so be prepared to buy a new one.

 

hhott71, I don't know if you looked to see how we got here, but I just replaced the whole system about 2 weeks ago. So I don't think that is the problem.

Update, since I have not really been getting any more feedback I started doing some more looking around. I don't know if the diesel compressor or pully size is different because the RPMs are lower than a gas engine. But I thought I would check everything out on idle instead of 1500 RPMs. At idle the compressor was kicking in and out on low pressure. I started adding 134a very slowly until the compressor would run on long cycles. I only had to add 1 oz, 2 at the very most. The high side pressure really didn't increase as I added, the only real pressure increases were to the low side. I forget the temp (75 - 80), but now the high side stays at 250 psi and the low side is about 30 -32 psi. I don't think you can go any lower with the charge becuase of the low side pressures being too low. Plus the on off would have to wear out the clutch on the front of the compressor out.

It is working very well now. Hope it stays that way.

 

It sounds to me like the system is over charged. On a 134 system the high side pressure should be 2.5 times ambient at the highest. 2.2 is a better figure depending on air flow across the condensor at the time. 2.5 times 80 would only be 200.

Getting the correct charge in a 134 system can be tricky. I have found that charging by weight gives me the most consistent results. The key is to thoroughly evacuate and then use a charging scale to put the precise refrigerant quantity by weight using a charging scale.

A couple of years ago I bought a charging scale off Ebay for $80. It has turned out to be one of the most valued pieces of a/c equipment that I have.

Hope this helps.

 

Lots of good information here guys! FTE is the best, some real knowledgeable people who are not afraid to help. Love it!

 

I have the same truck and same issue. After reading the TSB from Ford it seems to be a very common problem. Pulled the orifice tube and it was clogged with the gritty green mess. Can the system be flushed and recharged?