A/C system - how to remove the cooling unit, evaporator, expansion valve (3 Viewers)

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While a small amount of oil might escape the compressor over time and high demand usage, I can find no benefit from any significant amount of oil in the other parts of the system. Compressor oil capacity for a 1994 Landcruiser 134a system is dictated by the compressor manufacturer. For component replacement as follows:
Receiver 10cc
Condensor 40cc
Evaporator 40 cc
Compressor 120 cc
These amounts are not cumulative. Sounds like your new compressor came with the proper amount of oil. Overfilling it can seize the compressor...
 
You will be adding PAG46/ND-8 oil to the following components...in the following amounts.

Begin by completely draining the compressor of the shipping oil. Do this thoroughly.

Add 1.5 ounces directly into your new condenser. Add 1.5 ounces directly into your new evaporator. Add .5 ounce directly into your new drier. Assemble parts. Add 4.2 to 4.5 ounces directly into your new compressor, turn slowly by hand to distribute. Install the manifold off of your old compressor onto the top of the new compressor. Use a NEW seal.

'Total' oil capacity will now be about 8 fl. ounces or just under (for the entire system).
OK, I am confused by this. The FSM says to add the oil to the compressor if I am replacing the parts mentioned, which now has 125 ML (4.2 ounces) in it. You are saying I should add the oil directly into the components. I already reinstalled the evaporator without adding any oil to it, but I can pull it back out and add some if that is the proper method.

Why does the FSM tell you to just add the oil to the compressor if what you are saying is the proper method?

Also, I reused the shipping oil and just added a little ND-8 that I bought for this project to that. Is the shipping oil the wrong stuff? Why would they put the wrong oil in the new compressor?
 
I would use NEW oil ND8. Do not overfill the compressor. I say again, DO NOT OVERFILL THE COMPRESSOR- in the voice of Pete from OBWAT...
 
Does anyone happen to have a photo of how the tension pulley for the compressor is supposed to look? I removed that about two years ago and I bought a new bolt that threads into the pulley, but it seems like I am missing something that would make it so that the bolt can be adjusted.

This is what I have. Should there also be a nut on there so that it would hold against the bracket?

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OK, I am confused by this. The FSM says to add the oil to the compressor if I am replacing the parts mentioned, which now has 125 ML (4.2 ounces) in it. You are saying I should add the oil directly into the components. I already reinstalled the evaporator without adding any oil to it, but I can pull it back out and add some if that is the proper method.

No...don't remove the evaporator at this juncture. If the evaporator is the only component you have installed then you have two choices.

1. Remove the high side line (the lower, smaller line) at the firewall where it connects to the Evaporator and add the oil there (use a syringe).

2. Don't worry about it and once you have charged the first can of refrigerant into vacuum at the high side (engine off) you can rotate the compressor BY HAND (belt off) 15-20 revolutions to move some of the oil and liquid refrigerant though the system.


Why does the FSM tell you to just add the oil to the compressor if what you are saying is the proper method?

I have no idea what your FSM says (if for a 94 model) but I can tell you that 'current' best practice when replacing components is to add the oil directly to the component(s). This insures that oil 'return' will happen as quickly as possible. Otherwise...upon start up (full charge of oil in the compressor) you have essentially slugged the compressor.

The lubricating oil is meant to be semi-suspended (miscible) in the refrigerant and carried throughout the system (in a ratio) by the refrigerant. It isn't supposed to 'pool' (significantly) anywhere, although as the liquid refrigerant turns to a gaseous state when entering the evaporator some oil does 'drop out'. Also, at certain temperatures (Critical Solubility Temperature) the oil will begin to drop out. Starting up a new system with ALL the oil in the compressor is hard on the compressor at initial start up and only prolongs the solubility process. In short...there is a better way!


Also, I reused the shipping oil and just added a little ND-8 that I bought for this project to that.

ND-8 is simply Denso's version of PAG oil. Any PAG-46 is the same thing so don't bother chasing down ND-8.

Is the shipping oil the wrong stuff? Why would they put the wrong oil in the new compressor?

The shipping oil is 'supposed' to be the type of refrigerant lubricating oil appropriate for your system. But who knows its origin, quality or condition? All PAG oils are highly hygroscopic (attract water/moisture), so it is common practice among A/C professionals to dispense with the oil shipped in a new compressor and refill with fresh oil of known condition. But...I leave that up to you.

^^^^^^ Expand for replies
 
Does anyone happen to have a photo of how the tension pulley for the compressor is supposed to look? I removed that about two years ago and I bought a new bolt that threads into the pulley, but it seems like I am missing something that would make it so that the bolt can be adjusted.

This is what I have. Should there also be a nut on there so that it would hold against the bracket?

Assuming you have the rest of the bracket...then yes...the locking nut is only thing missing from your set up.
 
^^^^^^ Expand for replies


OK, I think I will just leave the evaporator installed and then remove some of the oil out of the compressor and put it in the other components and then do as you said as far as spinning the compressor by hand or add some with a syringe to the evaporator.

I will also just add a locking nut to the tension pulley assembly and go from there.

Thanks again for the responses! This is all new territory for me and the FSM vs. what you guys are saying had me scratching my head.
 
Does anyone have a photo of the water temp switch connection into the witing harness. It think I must have lost a pigtail. Perhaps a little birdie stole it...
 
These amounts are not cumulative. Sounds like your new compressor came with the proper amount of oil. Overfilling it can seize the compressor...

Yes and Yes.

The OP states he poured out about 4.2 ounces of oil from the new compressor. The reason for that amount is because the manufacturer 'assumes' that the compressor is only component being replaced AND that the system is/was fully and properly charged with 7.6 to 8.0 ounces of oil to begin with.

So...the 4.2 to 4.5 in the compressor when added to the .5 for the drier, 1.5 for condenser and 1.5 for the evaporator is cumulatively 7.7 to 8.0 ounces.

The amount of oil in the new/re-manufactured compressor varies from being the correct amount for the compressor only...to the full amount for the entire system.

That is why it is important to drain the compressor to see how much is in there. Further....I recommend folks consider any oil in the compressor to be regarded as 'shipping' oil (since we can not verify what it is) and to replace it with fresh oil in an appropriate amount.

And yes, overfilling a new compressor (not first hand turning it before initial start up) is a patently bad idea.
 
OK, I think I will just leave the evaporator installed and then remove some of the oil out of the compressor and put it in the other components and then do as you said as far as spinning the compressor by hand or add some with a syringe to the evaporator.

I will also just add a locking nut to the tension pulley assembly and go from there.

Thanks again for the responses! This is all new territory for me and the FSM vs. what you guys are saying had me scratching my head.

Understand completely. Sounds like you have it on the run now. Let us know if have any other questions. You don't want to do A/C work more than once.
 
Yes and Yes.

The OP states he poured out about 4.2 ounces of oil from the new compressor. The reason for that amount is because the manufacturer 'assumes' that the compressor is only component being replaced AND that the system is/was fully and properly charged with 7.6 to 8.0 ounces of oil to begin with.

So...the 4.2 to 4.5 in the compressor when added to the .5 for the drier, 1.5 for condenser and 1.5 for the evaporator is cumulatively 7.7 to 8.0 ounces.

The amount of oil in the new/re-manufactured compressor varies from being the correct amount for the compressor only...to the full amount for the entire system.

That is why it is important to drain the compressor to see how much is in there. Further....I recommend folks consider any oil in the compressor to be regarded as 'shipping' oil (since we can not verify what it is) and to replace it with fresh oil in an appropriate amount.

And yes, overfilling a new compressor (not first hand turning it before initial start up) is a patently bad idea.


OK, so now I am back to having a little confusion. This is a Denso compressor and it has the same stamping, etc as the original. It currently has a mix of the "shipping oil" plus another 25 ML of Denso oil that I added to it assuming that they put the correct oil in it from the factory for a total of 125 ML(4.2 ounces). That is the only oil in the system as of now. I flushed the lines with the AC flushing product I listed earlier and ran a bunch of air through the lines at that time to blow out any old crud.

So what I think you are saying now is that I should add the additional amounts into the other components. I am going to run out of oil if I throw the oil that is currently in the compressor out, but I should have enough to add the amounts listed for the other components. I guess I could err on the side of caution and dump the oil that is currently in the compressor, but I am not sure I will be able to source more oil locally which would delay this project and I really don't want to do that unless I have to.

Thoughts?
 
OK, so now I am back to having a little confusion. This is a Denso compressor and it has the same stamping, etc as the original. It currently has a mix of the "shipping oil" plus another 25 ML of Denso oil that I added to it assuming that they put the correct oil in it from the factory for a total of 125 ML(4.2 ounces). That is the only oil in the system as of now. I flushed the lines with the AC flushing product I listed earlier and ran a bunch of air through the lines at that time to blow out any old crud.

So what I think you are saying now is that I should add the additional amounts into the other components. I am going to run out of oil if I throw the oil that is currently in the compressor out, but I should have enough to add the amounts listed for the other components. I guess I could err on the side of caution and dump the oil that is currently in the compressor, but I am not sure I will be able to source more oil locally which would delay this project and I really don't want to do that unless I have to.

Thoughts?

What we are shooting for is 7.6 to 8.0 ounces of oil for the entire system. So...if I am understanding you correctly, you added about .8 ounce to the amount of oil that you poured out of the compressor and NOW you have (total) 4.2 ounces in the compressor? IF so....then you have exactly the right amount for the compressor.

But you still lack 3.8 ounces for the rest of the system. So by adding .5 to the drier, 1.5 to the condenser and 1.5 to the evaporator (that would be an additional 3.5 ounces) it would bring your system total to 7.7 ounces. Perfect!

As previously discussed...you can do this one of two ways:

1. (The preferred method) is to add the oil to each individual component. You already have all the oil necessary in your compressor. So just add the additional amounts above to the components... and you are done.
OR.......
2. Add an additional 3.5 ounces of oil to your compressor and hand turn the compressor 15-20 full revolutions so you don't slug the compressor upon initial start up. But I much prefer method #1 for a variety of reasons.

^^^ Note to the above: If you elect to add all of the oil to the compressor then plan on charging the first can of refrigerant into vacuum as a liquid through the high side (engine off). Then hand turn the compressor.

In the future...dispense with any oil that came with the compressor. Only for the reason that we don't know its origin or condition. Not saying it isn't correct or shouldn't be serviceable....just saying we don't know.
 
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What we are shooting for is 7.6 to 8.0 ounces of oil for the entire system. So...if I am understanding you correctly, you added about .8 ounce to the amount of oil that you poured out of the compressor and NOW you have (total) 4.2 ounces in the compressor? IF so....then you have exactly the right amount for the compressor.

But you still lack 3.8 ounces for the rest of the system. So by adding .5 to the drier, 1.5 to the condenser and 1.5 to the evaporator (that would be an additional 3.5 ounces) it would bring your system total to 7.7 ounces. Perfect!

As previously discussed...you can do this one of two ways:

1. (The preferred method) is to add the oil to each individual component. You already have all the oil necessary in your compressor. So just add the additional amounts above to the components... and you are done.
OR.......
2. Add an additional 3.5 ounces of oil to your compressor and hand turn the compressor 15-20 full revolutions so you don't slug the compressor upon initial start up. But I much prefer method #1 for a variety of reasons.

In the future...dispense with any oil that came with the compressor. Only for the reason that we don't know its origin or condition. Not saying it isn't correct or shouldn't be serviceable....just saying we don't know.


OK, thanks for the clarification. What you said is the situation I am in. I will just add oil to the other components and keep moving. I will take the risk that the oil that came in the compressor is the right stuff since the directions don't call for disposing it.

Thanks again!
 
OK, thanks for the clarification. What you said is the situation I am in. I will just add oil to the other components and keep moving. I will take the risk that the oil that came in the compressor is the right stuff since the directions don't call for disposing it.

Thanks again!

Da Nada. Go kick it's A$$.
 
I'm going to tackle this sort of job at some point with my 80 but in addition I also need to replace the air box assembly in the middle as mine has some issues with dampers/flaps not operating correctly. I have not tried to do a 'whole dash removal' as I think that's required to do more than just get at the blower fan and the AC evap unit.
 
I'm going to tackle this sort of job at some point with my 80 but in addition I also need to replace the air box assembly in the middle as mine has some issues with dampers/flaps not operating correctly. I have not tried to do a 'whole dash removal' as I think that's required to do more than just get at the blower fan and the AC evap unit.

Correct. Beyond removing the evaporator or blower motor....it gets pretty involved.

IF you need to get to a heater core or the Dampers/flaps/blend doors then you can expect to get knee deep into the dash.
 

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