Really weird air conditioning problem

I have an 86 dually with a 2005 6.0 in it. The truck had the 454 with that giant stock compressor filled with r134 and the sticker said pag oil and the AC worked pretty good. Now I'm using a brand new 2005 style compressor and everything else is the same. I pulled out the orifice tube and cleaned it while I was at it and put a new acumilator/drier on.

I vacuumed it for an hour and put 2, 12 ounce cans in it. The new compresor said it was prep filled with oil.

The compressor ran for about 1 minute once the pressure switch closed and then the compressor almost locked up and the clutch was slipping. I got pretty mad and gave up for the day.

Yesterday I checked it out again. I put the gauge on it when the truck was off just sitting for a few days and it read about 40 psi on the acumilator. I started it up and turned on the AC. The pressure started climbing so I let some out and the compressor stayed running. The dried started to get cold. Then the pressure pegged the gauge well over 100 psi and the compressor locked up again and the clutch started slipping.

I let a lot out to get back around 30 psi and the compressor was running. Everything got hot, drier, high side line, low side line. I started slowly putting more in, the pressure was slowly increasing but nothing got cold. Again all of a sudden, around 40 psi the compressor locked up and the pressure pegged the gauge.

I'm stumped, and frustrated because we booked a camping trip in 2 weeks and the wife will be pissed if the truck isn't ready. The dog can't take the heat

Are you sure the compressor had enough oil in it? I usually I drain & measure any oil when shipped, then add if needed the recommended amount.

Can you get a gauge set for both high and low side pressures? 100 psi assume low side? If that's the case something is restricting flow. Likely orifice tube. Not a good idea to clean it. They are inexpensive. Is it correct for 134a?

Agree with previous poster on oil. Some compressors are shipped without any oil, others correct amount and still others need to be drained and oil quantity adjusted. Also need to add oil for the new drier.

Another thought, are you sure the high and low side lines are on the correct compressor ports?

Rickf said:

Are you sure the compressor had enough oil in it? I usually I drain & measure any oil when shipped, then add if needed the recommended amount.

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No, I don't know much about AC stuff. There was a tag on the compressor that said it was pre filled don't add oil so I figured that was good

fast 99 said:

Can you get a gauge set for both high and low side pressures? 100 psi assume low side? If that's the case something is restricting flow. Likely orifice tube. Not a good idea to clean it. They are inexpensive. Is it correct for 134a?

Agree with previous poster on oil. Some compressors are shipped without any oil, others correct amount and still others need to be drained and oil quantity adjusted. Also need to add oil for the new drier.

Another thought, are you sure the high and low side lines are on the correct compressor ports?

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I have the hobo freight gauge set. I was just using one of the cheap fill hose gauge things yesterday though. Yeah I was just using the low side port on the drier. I got a new orifice tube but it must have been the wrong one so I just cleaned the old one. Yup 134a.
I have an 02 Silverado and I copied off that one

louu said:

I'm stumped, and frustrated because we booked a camping trip in 2 weeks and the wife will be pissed if the truck isn't ready. The dog can't take the heat

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She can't be that bad looking?

Tell us about your engine fan / condenser fan.

Most AC compressors have about 2.5 to 3.0 ozs in them. the system will take about 5 to 7 ozs so thinking that you didnt have enough oil in it!!

Rickf said:

Are you sure the compressor had enough oil in it? I usually I drain & measure any oil when shipped, then add if needed the recommended amount.

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CorvairGeek said:

Tell us about your engine fan / condenser fan.

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LINE MAKER 89 said:

Most AC compressors have about 2.5 to 3.0 ozs in them. the system will take about 5 to 7 ozs so thinking that you didnt have enough oil in it!!

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It has the stock condenser from the big block setup, it all worked with the massive compressor before I did the swap. I have 3 fans on it, the stock little one on the front of everything and 2 spal fans on the back of the radiator in a nice aluminum shroud.

So I put a new compressor on again and checked the oriface tube. It was clogged up with junk, it only ran for 10 minutes or so. I wish I would have just replaced everything when it was all apart. It kinda works now but isn't ice cold. This winter I'm going to tear everything out and replace everything. I doubt I can flush the system in place and get it clean enough.

I'm guessing the clogged tube is what caused the compressor to lock up. The new compressor was shrink wrapped and had bolt on caps over the openings and said it's filled with the proper amount of oil, don't add oil

When I upgraded my system from R12, I replaced everything under the hood, then flushed out the evaporator. I can get 40* out of the drivers side vent, it is a single cab, your results may differ.

@louu What brand compressors? If the first one failed, shrapnel will stick in the condenser and evaporator. Whole system needs to be flushed. If I read this right, you took out the orifice tube twice, and both times it was clogged up.

SquareRoot said:

She can't be that bad looking?

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Yo Mike, that's just wrong, but funny!

Rickf said:

When I upgraded my system from R12, I replaced everything under the hood, then flushed out the evaporator. I can get 40* out of the drivers side vent, it is a single cab, your results may differ.

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I'm jealous, 40 is amazing! Mine never got that cold with the old big block setup. It was comfortable but not that cold.

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Turbo4whl said:

@louu What brand compressors? If the first one failed, shrapnel will stick in the condenser and evaporator. Whole system needs to be flushed. If I read this right, you took out the orifice tube twice, and both times it was clogged up.


Yo Mike, that's just wrong, but funny!

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Odd brands from the jungle website, the first one was UAC and the one on there now is RYC.

The first time when I was. Setting it up I wouldn't say it was clogged just a little dingy from being in there who knows how long.

The second time when I took it out after the compressor locked up it was definitely clogged. I blew out the evap and condenser with air but was nervous to use flush stuff because I don't know if it will all come out with everything installed in the truck still.