Changed my whole AC system over memorial weekend, and recharged the system but need help pls

[100Seriesforlife]

Hi! Glad to be part of the community.

I recently had the AC compressor I installed when I bought the car fail. Looking back, I think it happened because I was inexperienced at the time and only replaced the compressor without addressing the rest of the AC system.

This time, I wanted to do it correctly, so I replaced the AC compressor, condenser, and both the front and rear expansion valves. I also thoroughly flushed the AC lines and made sure any debris or old fluid was removed. I replaced the PAG oil for the entire system as mentioned before on this forum (i think around 9 fl oz total).

After vacuuming the system, it held vacuum properly, so I vacuumed more and proceeded with charging it. I added the refrigerant amount listed on the under-hood sticker, but my pressure readings are slightly higher than what the FSM specifies. The AC cools properly, though.

I know the FSM provides different diagnostic scenarios, but mine doesn’t seem to match any of them — both the low and high side pressures are a little higher than spec, yet cooling performance is good and there are no bubbles visible in the sight glass. For reference, the ambient temperature here is around 70°F and humid. I attached a photo of my gauge readings along with the FSM chart for comparison.

Has anyone experienced something similar? Am I okay to continue using the AC as-is even with the slightly elevated low- and high-side pressures?

Thanks!

 

[vipergrhd]

Did you put all the oil in the compressor, or did you distribute among the other components? Is 9 oz the spec. for the entire system? My guess is the oil is causing a slight back up in your system I could be wrong, but it is possible with that much oil in the system. What temperature is coming out of the vents? Just for chits the bubble gauge thing is useless for R134 refrigerant they use it for R12 back then.

 

[100Seriesforlife]

Don't have a thermometer at the moment unfortunately, need to get one and check but its very cold air coming out of the vents.

The ac compressor came pre-charged with 6 fl-oz and i added approximately 3ish fl-oz to the ac lines. I think 9 ish is the full system capacity as older threads said on here.

 

[styran]

did you charge by weight? thats how all modern cars inducing this one are charged.
the sticker under the hood has the exact weight you need for the system to properly operate.
did you do a proper evacuation with a micron gauge so you can tell when you have reached sufficient vacuum? or guess with your HF manifold gauge?
have you confirmed the oil capacity with the FSM?
id guess you are over charged. especially if you never weigh anything in. that is guessing

 

[100Seriesforlife]

did you charge by weight? thats how all modern cars inducing this one are charged.
the sticker under the hood has the exact weight you need for the system to properly operate.
did you do a proper evacuation with a micron gauge so you can tell when you have reached sufficient vacuum? or guess with your HF manifold gauge?
have you confirmed the oil capacity with the FSM?
id guess you are over charged. especially if you never weigh anything in. that is guessing

I did put exactly the amount of refrigerant in weight as specified in the sticker.

I did vacuum for a long time before I recharged ( total of 6ish hours) but i didn’t use microm gauge cause i don’t have one.

The fsm doesn’t give you the whole pag oil capacity but tells you how much to put when you change each part. I used the thread attached below to come up with “9” as the capacity but i might be wrong

S

Thread 'AC system PAG oil capacity'

Aug 24, 2021

I am trying to clarify the pag 46 oil capacity for the total ac system. This is for a 2000 model year lc100 with both front and rear evaporators and a central coolbox. The workshop manual states that 1.4 fl.oz (40 cc) should be added when any of the evaporators are replaced. If the condenser with receiver/dryer is replaced then it needs 1.7 fl.oz (50 cc) to be added to the system. This is a total of 5.9 fl.oz (170 cc) without counting the compressor.

The rule for replacing the compressor is to drain the oil from the old one and measure the amount. The new compressor should also be drained...

• SimpleTruth
• Replies: 3
• Forum: 100-Series Cruisers

 

[vipergrhd]

What is the sticker saying in regard to oil capacity? Did you use 12 oz. can to charge the system? If you are blowing anywhere 45* and below @ 70* ambient that is good. I really think you put too much oil, I usually empty the compressor and measure the oil and put back about 2-3 oz and spread out the rest or add later if you have an injector.

Don't have a thermometer at the moment unfortunately, need to get one and check but its very cold air coming out of the vents.

The ac compressor came pre-charged with 6 fl-oz and i added approximately 3ish fl-oz to the ac lines. I think 9 ish is the full system capacity as older threads said on here.

 

[styran]

I did put exactly the amount of refrigerant in weight as specified in the sticker.

I did vacuum for a long time before I recharged ( total of 6ish hours) but i didn’t use microm gauge cause i don’t have one.

The fsm doesn’t give you the whole pag oil capacity but tells you how much to put when you change each part. I used the thread attached below to come up with “9” as the capacity but i might be wrong

S

Thread 'AC system PAG oil capacity'

Aug 24, 2021

I am trying to clarify the pag 46 oil capacity for the total ac system. This is for a 2000 model year lc100 with both front and rear evaporators and a central coolbox. The workshop manual states that 1.4 fl.oz (40 cc) should be added when any of the evaporators are replaced. If the condenser with receiver/dryer is replaced then it needs 1.7 fl.oz (50 cc) to be added to the system. This is a total of 5.9 fl.oz (170 cc) without counting the compressor.

The rule for replacing the compressor is to drain the oil from the old one and measure the amount. The new compressor should also be drained...

• SimpleTruth
• Replies: 3
• Forum: 100-Series Cruisers

well you did the right thing. go enjoy your AC!
highly recommend you pick up a micron gauge. it'll you if you can stop vacuuming or need to vacuum more.
limiting the system and oil's exposure to moisture is key to success

 

[100Seriesforlife]

What is the sticker saying in regard to oil capacity? Did you use 12 oz. can to charge the system? If you are blowing anywhere 45* and below @ 70* ambient that is good. I really think you put too much oil, I usually empty the compressor and measure the oil and put back about 2-3 oz and spread out the rest or add later if you have an injector.

I used 3 of the 12oz cans, the sticker is as below. I might have put a little bit too much oil as well but hopefully that wouldn’t be an issue. It’s blowing better than 45 i think.

 

[100Seriesforlife]

well you did the right thing. go enjoy your AC!
highly recommend you pick up a micron gauge. it'll you if you can stop vacuuming or need to vacuum more.
limiting the system and oil's exposure to moisture is key to success

I really hope so, this AC work was no joke but definitely doable. I will get a micron gauge if i come across one forsure!

 

[jsloden]

As long as you put the proper amount of freon in by weight and you put the correct amount of oil in and you don't have any leaks you should be good to go. As long as it's blowing cold it should be good. The oil will eventually make it's way around the system. I know you've already replaced the components but hopefully you used good quality parts. I would recommend either nissens or denso for the ac compressor.

 

[vipergrhd]

I used 3 of the 12oz cans, the sticker is as below. I might have put a little bit too much oil as well but hopefully that wouldn’t be an issue. It’s blowing better than 45 i think.

View attachment 4147867

I really hope so, this AC work was no joke but definitely doable. I will get a micron gauge if i come across one forsure!

Ok, three cans is 36 ounces. Max is at 2.42 lbs which is equal to 38.72 ounces meaning you are under the max requirement. Chances are you are over charged with oil I could not find the actual amount in my spec. list at the moment. Maybe Styran could donate a Micron gauge?

 

[adventurezoutside]

id guess too much oil, always weigh your refrigerent

 

[100Seriesforlife]

Ok, three cans is 36 ounces. Max is at 2.42 lbs which is equal to 38.72 ounces meaning you are under the max requirement. Chances are you are over charged with oil I could not find the actual amount in my spec. list at the moment. Maybe Styran could donate a Micron gauge?

How bad to run it as is? Cause not sure how to remove the excess oil tbh other than doing everything all over again. I was reading that i need extra 2 fl-oz or more to be bad but not sure how accurate that is.

 

[styran]

How bad to run it as is? Cause not sure how to remove the excess oil tbh other than doing everything all over again. I was reading that i need extra 2 fl-oz or more to be bad but not sure how accurate that is.

too much oil reduces cooling performance. too little oil damages compressor. youre gonna have to reflush to remove oil. if you charged within the weight range on the sticker, and it cools good now go enjoy your ac.

 

[100Seriesforlife]

Sounds good!

Thank you so much everyone, I truly appreciate your input!!

 

[vipergrhd]

How bad to run it as is? Cause not sure how to remove the excess oil tbh other than doing everything all over again. I was reading that i need extra 2 fl-oz or more to be bad but not sure how accurate that is.

If your current readings stay the same, we are not in summer just yet and your high side is already up there, rule of thumb is 100 psi plus ambient is ideal also having too much oil is not good for your compressor it was not designed to push liquid. For now it will be ok but I highly suggest take it to a shop that will Evac and recharge the system maybe two times or more depending how much oil is extracted. Explain to the shop what you did and you want to remove the excess oil and recharge the system to proper weight I would have it at Max just for chits. Hope this helps in some way.

 

[styran]

If your current readings stay the same, we are not in summer just yet and your high side is already up there, rule of thumb is 100 psi plus ambient is ideal also having too much oil is not good for your compressor it was not designed to push liquid. For now it will be ok but I highly suggest take it to a shop that will Evac and recharge the system maybe two times or more depending how much oil is extracted. Explain to the shop what you did and you want to remove the excess oil and recharge the system to proper weight I would have it at Max just for chits. Hope this helps in some way.

you cannot tell how much charge is in there by pressure. every car is different when it comes to pressures.
i've had vehicles showing "normal" pressure and end up being at 20% capacity.

lots of things can cause high side pressure.
biggest one is lack of airflow, especially when stationary, very common on fan clutch models.

we charge by weight not pressure. if he charged the right weight hes done.
if you think you are under/overcharged just by looking at pressure alone you are wasting your time unless you see outrageously high values

only way to know is pull the charge out or follow the FSM procedure with the sight glass to the T. correct RPM, etc.


as for the oil, you have to severely over the capacity for the oil to ever damage the compressor.
if it cools fine leave it be.