How important is it to replace the Receiver/Dryer when the system has been open for 3 months? Can a vacuum down of the system assure things will be fine if I keep the old one on there?

Also...where is the Oriface Tube located?
How do you replace that?

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If you want it to last do it right, everyone that sells rebuilds pushes replacing both. It has been awhile since I did that job but I think the orifice tube is in of of the connections to the receiver.

 

You should not have a recover dryer or orifice tube if this is on your 98 T/A… you will have a thermal expansion valve instead of an orifice tube and an accumulator rather then a recover dryer, they accomplish the same thing just but a very different part if you smell what im stepping in. But either way it is a good idea to replace the accumulator when opening the ac system for an extended period of time or when replacing a component, in fact most parts manufactures will require the accumulator/ receiver dryer when replacing a part of the system if you want your warranty.


That being said accumulators tend to be a little cheaper then receiver dryers so I would go ahead and change that out… but make sure it is the very last thing you do, and then vac down the system and you should be good to go.

As far as the thermal expansion valve, it is on the inlet side of the evaporator, it is similar to a fixed orifice tube. It separates the high from low side turning a high pressure liquid into a low pressure liquid just like an orifice. But it does control how much is going into the evaporator and can completely stop flow, were a fixed orifice is always allowing flow. The thermal expansion valve has a temperature probe on/near the evaporator and will adjust the amount of refrigerant needed based on its temp (if the evaporator is warmer it will allow referent in, if it is too cold it will not allow any in).

Sorry if thing was a little long but I think ac systems are cool, yes I’m weird like that haha
This really just scratches the surface I am sure someone on here has more experience with this system specifically and could probably go into more detail then me.

 

98 TA will use an orifice tube. It will be located at the high pressure inlet of the evap. Yes, you must replace the accumulator. The dessicant will be damaged because it's been sucking water out of the air for 3 months.

 

Rockauto.com

OK....so if I buy this for $35.00 I'll be set?
http://www.rockauto.com/catalog/moreinfo.php?pk=83075


Also, they only list Oriface Tubes under 1998 Firebird.......can't find Expansion Valve anywhere.

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I’m sorry I was mistaken about the expansion valve I looked it up on all data today an it does have an orifice; I think the earlier ones had an expansion valve.

But that accumulator should work… why did you take it off in the first place

 

Its still on the car. But I removed my 427ci a couple months ago and I had to disconnect the A/C system. Plus, I bought a new compressor A/C line and a new condensor is going in while I'm doing the engine swap.

So the system has been wide open that long. I figured I'd change the accumulator while I'm at it.

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they are $28 for a dryer at napa

 

I just went ahead and bought all new AC Delco stuff for my car.....all engine/intake/TB sensors, a/c condensor, 02 sensors (Denso), and a bunch of other stuff.

Really going with rockauto.com, instead of PepBoys or Advance Auto or other local stores.......you can't beat the price to get all AC Delco stuff over the other aftermarket brands at local auto parts stores. Plus, rockauto.com has an online coupon that anyone can use for 5% off entire order. I bought like $300.00 worth of stuff.....amazing savings.

$35 for the AC Delco accumulator.dryer with hose assembly is really cheap.

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Ok that’s what I kind of figured. make sure you put oil back in the system after replacing the compressor. If you still had the covers that came on the parts that would be better, but you should be fine replacing accumulator and vacuuming it down.

 

Ok....in the past I put two cans of refrig in.....both cans have oil mixed in. Also, After I put one can in, I always put in just a small can of oil. Then I put the other refrig can in.

Always seemed to work perfect for years and years after doing that......

I'm using the same compressor I've had for the past 6 years.

Sound good....????

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Here is what GM says to do with my 93 when replacing components

Compressor assembly replaced
-If less than 30ml (1fluid once) is drained add 60ml (2 fluid ounces
-If more than 30ml (1 fluid ounce) is drained add same amount

Receiver and dehydrator assembly replaced
-add 30ml (1 fluid once) more than what was drained from the old receiver and dehydrator assembly

Evaporator replaced
-add 90ml (3 fluid ounces) oil

Condenser assembly
-add 30ml (1 fluid once) oil

Refrigerant oil loss do to large leak
-If the refrigerant charge is abruptly lost due to a large refrigerant leak, approximately 90ml (3 fluid ounces) of refrigerant oil will be carried out of the system suspended in the refrigerant. Any failure that caused abrupt refrigerant discharge will experience this oil loss. Failures that allow the refrigerant to seep or bleed over time do not experience this oil loss

*Again this is from GM for a 1993 camaro I do not own or claim to own it*

So if you replaced the accumulator and condenser you should replace the oil as needed, it would obviously be a good idea to find what is recommended for your system but it will most likely pretty close I have to book from 93 so those are the specs I have right now plus maybe someone will find them useful one day if they use the search tool.

Since you are going to use the compressor you have now it might be a good idea to drain the oil, measure how much you took out and simply replace it with the same amount of new oil. The book says it is recommended to add the oil directly to the component if possible. If you put the oil in this way you should now need to use the refrigerant with oil in it and just get pure 134-A. unfortunately there is really no way to tell exactly how much oil you have in your system without replacing every part or flush out every component, BUT if you replace the component with the recommended amount of oil and drain/ replace the oil in the compressor you should be pretty darn close to the correct amount.

If you would want to replace the refrigerant with the refrigerant/oil mix you might consider reading how much is in the can and subtracting that amount from the components that need oil put in them and then theoretically you should have the same amount of oil in the system. And of course use PAG oil gm says P/N 12345923 or equivalent. And before I forget don’t but any of that 134-A with stop leak garbage in it, its like putting slime in your tires and then going to get them changed it can be a mess and you just want to stay away from it.
To make a long story short this is the best way to do it, I have seen some pretty crazy things work that text books have under the do not do section haha. A/C systems are simple and complicated at the same time like any other system on a car; I am just trying to give you the most info I can. You sound like you have done this a couple of times and have a good grasp of how to work with A/C but more info never hurts and maybe someone will stumble across some of the ac posts and learn a little something.

If you need help finding specs on your system I might be able to help you find some of it on all data or Mitchell

 

Thanks....I'll add 3 ounces than.....

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no, sorry.

i did not read the whole thread and everyone's responses completely but, it is an orifice tube system with an accumulator. Buy a new accumulator and do not unpackage the accumulator until you are ready to install it and close the system. The accumulator has 2 purposes- make sure any liquid refrigerant on the suction side turns to a gas before entering the compressor (otherwise the compressor will 'hydrolock' on liquid and break) and it also has a dessicant in it to absorb moisture in the system which is very important.
The other thing which i don't know, and i don't think you went into detail about, is how much oil was lost from the system. If you overfill with oil you will have poor performance. There are recommendations for how much to re-add when putting in a new part such as an accumulator, or new lines or condenser and so on. What i would do is get a flush kit and flush the old oil out of the condenser and evaporator and all hoses, old oil is not good in anything. remove the compressor and drain that of its old oil and refill it with the correct amount of fresh oil for just the compressor. Pull the orifice tube out and inspect, if it's clean then reinstall. If it black and sludgy then definitely flush the entire system well (but not compressor) to remove old oil which was contaminated with moisture. If there are metal flakes on the orifice tube screen then you had compressor problems and you should also replace the condenser and really flush the evaporator well and consider a new compressor. Then add the correct amount of oil into the accumulator for the entire system minus what is already in the compressor unless you have an oil injection kit when charging with refrigerant. Then you [preferably purge and pressure check the system with nitrogren] then the pull a deep vacuum then charge with r134a the correct amount. that is how it is done correctly. the last big question is what equipment you have to pull a vacuum and what vacuum gauge do you have? you basically need a good accurate micron vacuum gauge to know you are getting all the moisture out of the system and that will also tell you if your vacuum pump is good enough. Charging the system with cans of refrigerant that has oil in them is basically guaranteeing work to an ac shop at a later date because you don't know nor are accurately controlling how much oil goes into the system which is important. if you were just working or replacing one component such as the accumulator and everything else was in good working order, then for an accumulator it's 2 ounces plus whatever oil was drained out of the old one, it's assumed the old accumulator has 2 ounces soaked into it which does not drain out and a new dry accumulator will require 2 ounces plus whatever was drained out the original one. Same applies for all other components in the system with the goal of having 9 ounces of oil in the system. And GM/delpi compressors use PAG 150 oil. If you replace the compressor then use whatever viscosity PAG oil that compressor manufacturer calls for.