Working on a 2001, and the compressor is OEM and uses 8oz of PAG 150.

The evaporator and condenser are already installed, and it does not seem feasible for me to get any oil in there. Maybe I can pour some down the low-side hose going into the condenser, but I don't know if that is no big deal or a terrible idea.

Would it be fine to just dump 2 oz in the accumulator, 6 oz in the compressor, and call it a day?

I have seen videos where they just dump the oil in the compressor, but they also weren't replacing every component. Meanwhile, I have a guide that suggests distributing the 8 oz across components (Condenser: 1 oz, Evap: 3 oz, Accum: 2 oz, Comp: 2 oz).

Also, for oil balancing, how do I drain the HT6? There is a bolt on the back, off-center on the high-side, opposite the pressure sensor. If I had to guess, this would be the drain plug. Do I need to uncover the ports while draining? When refilling, should I fill through the drain plug or the ports?

Thanks!

Answered a few, maybe all, of my own questions watching this .

H series does not have a crankcase (it's an axial compressor), and as such, seems to not have a plug, so oil is added and drained through the inlet port only and only half the system charge is added here, the other half going into the accumulator (for those of us with an orifice tube).

Something else I came across while researching today is that you want to hand turn the clutch after installation but before starting the engine in order to distribute the oil.

The guide of values I received for distributing oil throughout was probably for replacing individual components.

Any additional tips or helpful contributions are greatly appreciated.

 

You don't discuss exactly what your repair consisted of and for the benefit of others searching these threads I'll give you the entire spiel. The direct answer to your question is in bold:

The oil is distributed throughout the system in normal operation and the amount typically found in the various components is shown in the table that you have. This is a general guide since oil just ends up in locations other that the compressor as refrigerant circulates and is not needed anywhere except the compressor. Your system may not look like that chart. When replacing components, you lose the oil that is in that component. When flushing the system after a catastrophic compressor failure you lose all of the oil in the system. When refrigerant is recovered by a professional a small amount is removed and can be measured. It is critical for the level of total system oil to be correct and especially true that the compressor must contain its minimum amount to prevent failure. You also can have too much oil in the compressor, especially at start up so this must be considered. More on that later.

There are different types of oil and oil viscosity and it is important to use the proper one for the new or existing compressor, regardless of what oil the OEM compressor used (if replacing the compressor). The oil must match the compressor not the vehicle. Different compressor models have different tolerances and hence different oil viscosities. If you have a new compressor and it comes precharged with oil then that eliminates the whole debate over the proper oil for that compressor but not the determination of the proper amount of oil needed in the entire system.

When a component is replaced you determine the amount of oil that you are losing by draining and measuring it. This is especially true for the compressor or accumulator/receiver. In the case of parts that are difficult to drain like the condenser just use the oil quantity chart. In the case of a total system flush, use the system oil quantity spec.

If the compressor failed, also replace the orifice tube if so equipped and new orings for anything that got opened up. Always replace the accumulator when the system gets opened because of the descicant and get the system closed back up and evacuated as soon as possible.

If the compressor comes precharged with oil, drain and keep this oil in a clean container and pour back in the amount that you have lost from component removal by measurement or the oil distribution chart. If the system is flushed then the amount of oil equals the system oil level which as you pointed out is 8 oz for this vehicle. As to where to pour the oil when you need to put the entire 8 oz in the system, I have seen every version of this documented. All in the compressor through the correct amount in every component. I consider the later to be overkill. The oil ends up where it ends up but the important thing is the correct range in the compressor. The bare minimum amount that must be in the compressor no matter how much was removed from where is 2 oz. You can pour it all in the compressor or split it up as you have suggested with the correct amount in the accumulator (this is what I suggest). Either way, turn the compressor by hand 20 times after everything is assembled to start some of the oil on its way throughout the system if needed so that there is not too much in the compressor at start up. Remember that this oil is hygroscopic (absorbs moisture) so get everything closed up quickly, don't get half done and finish tomorrow.

Example: You drain the new compressor and it had 8 oz of oil in it. When you drained the old compressor and accumulator there was 5 ounces of total oil recovered. You then pour 5 oz of the new oil back into the new compressor and discard 3 oz of oil. If the new compressor is not precharged then you pour 5 oz of new oil into the new compressor from a bottle of the proper oil for that compressor. If the whole system is replaced or flushed then in the case of our trucks, pour 8 oz of oil into the system.

Do not just bolt up a new compressor with its oil precharge in it and let it rip. This will only work if the entire system was replaced or flushed and the precharge just happens to be 8 oz of oil. Too much oil will lead to reduced cooling capacity and if the excess is high enough, compressor failure. Less than 2 oz of oil in the compressor can lead to compressor failure.

Charge with dry nitrogen to 150 psi and check for leaks, then pull a proper vacuum for the proper time (minimum 30 minutes) then blank off the pump and check that this vacuum will hold for 20 min. Best is 500 microns, held for 20 min. If you only have a manifold gauge set then 28-30 in hg for 20 min. If you rise to 1500 microns then you still have moisture in the system, continue to vacuum. If you rise to atmospheric (0 on a manifold gauge set) then you have a leak, fix and repeat.

Charge the system to the name plate refrigerant weight under the hood or in your manual. Check pressures and vent temps.

What could be easier? LOL.


George

 

The compressor is the only part that can be damaged by lack of oil, so you're safe, IMO, putting it all in the compressor, as long as you rotate the compressor as George described to distribute it.

 

....how did you know? it started raining mid-job and was getting dark, so I had to call it, but the system is connected from accumulator through evap to condenser with acc-comp and cond-comp connections capped and plugged. is that still okay or do i need to take some remediating measures?

 

That's hard to say, its a matter of the descicant in the accumulator getting loaded with moisture and moisture starting to turn the oil into acid. If you have a micron gauge you can determine if you can get the system dry enough by seeing if you can hold 500 microns for 20 minutes after evac (might take longer than the default 30 min of vacuum as the moisture comes out storage). In the absence of a micron gauge, its a judgement call. Since you capped off the system and the oil is not in there yet you might be OK but I don't know that for sure. The risk is moisture+oil=acid=compressor failure=trashed system and significant R/R. The accumulator can handle a certain amount of moisture and keep the system safe but I don't know the limits in terms of days/hours open/capped/no vacuum. I remember a member here being critical of my detailed instructions and bragging about not vacuuming the system and not being careful with moisture stating that the system ran great. He was being cautious after I started ranting about venting refrigerant into the atmosphere being illegal but I presume that he "swept" the system with 134a as a hack to avoid a shop and their gear. He was "man" enough (sorry Christine) to come back a year or 2 later letting us know that he had a compressor failure. If they just seize cleanly its not too bad. If they puke up a bunch of metal and acid then its a mess to clean up because you also get a green goo thats hard to get rid of. Sounds like you tried to be careful by capping everything off so its a matter of risk management vs cost and time. I wouldn't want to repeat the process anytime soon so Id probably spend the $20 on a fresh accumulator (in fact that was my choice in similar circumstances 10 years ago, my very first AC job and I wanted it to go well). If your going to go for it, increase the vacuum time to at least an hour or until you can hold 500 microns for 20 min. I know that people generally prefer black and white but I live mostly in the gray areas (retired engineer and technical business problem solver).

George

 

nope, i had already added 2oz of oil to the accum because i thought the rest would probably go into the compressor only to be interrupted.

just drained the compressor and i managed to get almost 7 oz which makes me wonder if it already came with the full 8oz. The sticker on the compressor said "contains pag oil, follow oil balancing procedures", but it's an amber color, whereas the pag 150 oil from the bottle was blue. is this just shipping oil? if not, can i mix these 2 oils? the label on the compressor says RL488, which I found out was technically like PAG 125 or something (George I believe you actually helped in that thread as well lol), even though the guide from that thread noted that HT6 needs pag 150.

 

When I did a full AC replace, the only place I believe I put the oil was in the compressor.

I have a write up on what I did in my build thread that you might look at.

 

Oh oh, now your caught in the oil/compressor worm hole. As far as I know, when a compressor is shipped with an oil charge that’s the oil that the compressor is intended to be used with. I do not believe that there is a throwaway shipping oil placed in these units. As far as the quantity I assume that they ship with roughly the amount for the entire system so that you have that much if you need it but I have not replaced enough compressors to know if that’s always the case or not. As far as RL488 is concerned I see charts that show it as a PAG150 equivalent and also a PAG125 equivalent. The more common reference appears to be PAG150. As far as the color goes RL488 is listed as being blue. I have no idea if it’s OK to mix blue RL488 with amber colored peg 150 or not. As far as the viscosity goes this subject is way more complicated than it needs to be. Besides the fact that different manufacturers call for different oil viscosity, GM has issued multiple technical bulletins to change from 46 versus 150 s “universal” with differences between the style of the compressor which is further confusing. That’s why I always thought it was a good thing if the compressor came sealed with the oil charge from the factory because I figure that’s the best possible match. If a separate bottle is included then you don’t know if the distributor sent you the correct oil and if no oil is included then you spend a few days in this blender reading all these Forum posts and trying to get it figured out.

Try to stick with what came in the compressor if possible.


George

 

I think I remember hearing that it is good practice to pour out any oil that was shipped in a compressor and then return the exact amount you need. Ideally the amount with which it was shipped and how much is needed is the same but it is good to check these things.

 

so where does that leave me with regards to the 2 oz of oil that's already in the accumulator? should i trash the accumulator bc it is likely compromised?

christine, i have also seen posts saying that the shipping oil should be ditched. although four seasons usually notes what the case is when they ship out a compressor, that was not the case with Buy Auto Parts.

george, i think that, given the closeness in viscosity, if i mixed them, they would be relatively fine, so i'll probably dump and replace with the blue pag, but since there is probably some leftover oil in the compressor, there will be a little mixing.

going back to the accumulator, i think i would have risked it based on your initial write-up, but with some oil already in the accumulator, could it have really gotten that bad that quickly despite capping the system? in my mind, when you cap a bottle of oil that has been exposed to ambient environment, you are similarly trapping moisture. is that also an issue that people run into or is that situation not as bad?

really appreciating the help and discussion in this thread, learning a lot!