[blueblaze94]

I have a 1994 chevy blazer fullsize v8 , I have replaced condenser, accumulator, compressor, and orfice tube, I pull a vacuum no leaks, I can get one to one and a half cans in and when compressor is on the high side pressure just gets high over 400 psi I just shut it off, I am very frustrated and about to just take the ar-15 to the truck and get it over with! Need help please any information . Thanks

[smoothy]

Two questions... was the system flushed, and how many ounces of refridgerent are "one and a half cans". What does the manual say your system takes.

Cans come in different sizes, and without a refridgerant scale you should really charge to pressure based on the chart of the ambient temprature.

Sounds like either you have an orfice that's getting plugged or its overcharged.

Not a HVAC guy by trade, but I know my way around a system. And have a 609 license.

[blueblaze94]

One can is 12 oz. my brother has the same truck and it takes 3 and a half cans to fill it to the proper level. The system was not flushed. I know the lines are not blocked and I changed the ofice tube once . Due to the old compressor checked ofice tube and it was kind of nasty but not clogged . The high side should have been around 225- 350 psi. and thanks for the response. How often does a evaporator get clogged it looks brand new.

[smoothy]

If the orfice was cruddy... then everything else is cruddy as well. Why was the compressor replaced? Leaking seals or did it self destruct internally?

You REALLY should have flushed everything particularly after a compressor failure. How long did you pull a vacuum and how much of one.

Also how much oil did you put in... and what was the total amount your system would take after a flush.

The only way an evaporator would get clogged is if a compressor failure sent debris though the lines. The Crud comment you made has me thinking you have a lot of debris in the system potientually and it doesn't take much to wreck a system.

[blueblaze94]

I replaced the compressor cause it was still under warranty and it wouldn't kick on even with the low pressure switch jumped , but wwhen I took it off I could turn it fine and it looked OK on the inside. For the new compressor it had 1.5oz of oil already in it when I purchased it , I added 1.7oz of oil to it liquid oil through the suction side of the compressor , I asked everyone ac guy , autozone people they all said that that would be fine to add that in there so a total of 3.2 oz of oil. I pulled -30psi vacuum and let it sit over night and still -30psi when I checked it next morning. Still all it would ever hold even when I first got it was and to this day all I can get in it is 1.5 cans of freon.

[smoothy]

Ok, basically it sounds like you have gottten sound advice. ( I don't have acess to specs for that vehicle for actual ammounts based on what parts were replaced). Sounds like it was a clutch failure if it didn't kick on even when jumped so no fear of "Black Death".

Sounds to me like a blocked orfice tube (or an expansion valve for vehicles equipped with one of those instead). Without a compressor failure there is no way you should have enough debris to block the evaporator.

[blueblaze94]

Any other reasons it would do that? I will change the orfice tube . Can you think of anything else tha tmay clog it up and make it have high pressure

[smoothy]

You are compressing the refridgerant up against a blockage, I'm surprised at 400 psi it didn't automatically vent. On a system that had no other failure that's the most likely point... there is effectively no other restriction in the system normally, and the restiction is how you drop the pressure to get the cooling effect of evaporation while being abble to compress that same redigerant back up to a high pressure.

HOW enough to block the evaporator would get there is something I can't guess.

Why was the Condenser replaced, I assume it wasn't leaking or was it? The Accumulator (also known as receiver dryer) would be replaced any time the system is opened.

[blueblaze94]

Condenser was replaced cause the orfice tube was stuck , and I was trying to get it out and it broke off half way so I just replaced the condenser . What would be the out come if you didn't replace the accumulator every time the system is open? Vaccumming it shoulf get the moisture out correct? I have another condenser on the way . But I would hate to put it on if it is just going to do the same thing again. If I pull the evaporator off and flush it . How do I go aboutdoing that? And will I need to replace the accumulator again when I pull the condenser and evaporator off? Thanks

[smoothy]

THe accumulator has a dessicant in it... to suck up what little moisture remains after a proper vacuuming. Consider it a one time use item. It WILL bite you in the butt down the road.

Vacuuming might get the moisture out of most of the system but not the accumulator dryer. Yeah, that will need replaces EVERY time you open the system to the air. Considering the cost of everything else... skrimping there can cost you the entire system down the road. And yeah, its capacity is low enough it won't do its job twice. And you don't pull its caps of until the moment its getting attached and the vacuum pump is put on shortly afterwards. It's the LAST thing you put in the system before vacuuming.

[blueblaze94]

So it is under warranty still , will they take it back ? And give me a new one,

[smoothy]

so it is under warranty still , will they take it back ? and give me a new one,

Not the accumulator... consider it the cost of doing the work. Trust me, had to do that myself when a new expansion valve stuck closed on a car I was rebuilding the A/C system on. Didn't like having to buy a second receiver dryer but I wanted to do it right.

[blueblaze94]

The accumulator is under warranty , I already took one back . I will try to take this one back too.

[blueblaze94]

Maybe I didn't understand what you said. I need to replace the accumulator anytime that the lines are opened?

[smoothy]

maybe i didnt understand what you said. i need to replace the accumulator anytime that the lines are opened?

Yes... the accumulator also known as the Reciever/drier contains a small amount of dessicant to absorb any TINY amount of moisture that vacuuming the system didn't get. Its capacity isn't great enough to deal with a system that was opened twice. Moisture in the system will create acids that will eat away at all the metallic components from the inside. You get away with it in the short term, but in the long term the damage is very expensive to repair.

That's why failing to replace that part every time the system is opened to the atmosphere is considered being pennywise but pound foolish.

[blueblaze94]

OK , I understand, I will replace it as well. My condenser should be in today . Should I remove the evaporator and flush it?

[smoothy]

If you were to flush anything, I'd flush the entire system. Crud in one place equals crud everyplace. Oil does circulate thus it will carry it through the system.

You can't flush through a compressor, you can't flush through an expansion valve or orfice tube. You can flush through the rest. If you do it, use an approved A/C flush agent. Blow clean compressed air to make sure the system is dry, ideally nitrogen is optimum but few of us have access to that.

Also if you flush you need to replenish the oil that is distributed in those parts including hoses.

I like to do it because #1 you know its clean, #2 you will know EXACTLY how much oil is in the system because you will start from essentually zero. (I'd drain the compressor so I knew exactly how much I was putting in)

Too much oil and you can slug the compressor killing it... too little oil and you will wear out the compressor early.

Yeah you can take shortcuts by allowing a certain amount of oil per component and replace just the theoretical missing amount. Yes you can get away without flushing it as long as the reason you opened the system wasn't for a compressor failure or it wasn't open to the elements for an extended period.

With that said, I say what I say because I'm just the sort that likes to take the extra step for my personal peace of mind. And I like to keep my vehicles for a long time. I don't want to have to do a job a second time in the future.

Use fresh compatible O-rings (the Green ones are basically universally acceptable with different refridgerants) and I would put a compatible UV dye into the system before its charged otherwise it takes a special tool.. Helps making locate any leaks if you have any easier.

Since it appears you are doing this on your own vehicle the time is yours. If you were in a shop, time is money... and shortcuts make more sense.

[blueblaze94]

So when doing the flush I remove everything? Flush one thing at a time blow air into it to make dry! It is a brand new compressor should I flush it? It has ran maybe a total of 2 minutes. But all other componets I will flush . Where do I get the appropriate flushing stuff? Thanks

[smoothy]

Take the comressor off. Take the orfice tube out. Take the accumulator off. You can flush through what remains. You just can't flush through those three items.


You can drain the compressor. Its awkward to flush anyway. And that is mostly so you will know for certain exactly how much oil is in it when you reassemble the system.

Try your average autoparts store. Advance Auto has it as well as many of the smaller ones. You can get some that's in a can pressurized if you don't own a flush gun. There are a number of brands... but all will say they are AC system flush. They will all be R-134 comaptible as that's what all the newer vehicles use back into the mid 1990's. It should be near the R-134 stuff, or they may have it behind the counter, ask if you can't find it. Its really pretty easy stuff to find when you look for it.