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It came with oil I didn’t need to add any
Compressors never have enough oil for the whole system. Mine came with 3 ounces. The system needs 7.
 

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Discussion Starter · #42 ·
At this point, you really can't. If you had the machine, you would recover the refrigerant, pull a vac and recharge again. Since you don't really have that, you need to switch to using pressures.

I don't think you need to add much more, but do agree with Dwain that you need a little bit more. However it's possible that's because you didn't have the proper level of oil in the system.

WOuld need to see high side pressures here to really tell you next steps. Remember, you want to take your readings over 1500 RPM with fan to max and the doors open (to avoid any recirculating air). The goal is to cool purely 90 degree (or whatever outside temp is) across the evap and no recirculated air.

I don't have an SN95 service manual in front of me but I beleive low pressure cutoff is around 20psi. When you hook up the manifold guages with high/low pressure guages, pay attention to the low side when it drops and note where the pressure cuts off. When it cuts out, note the high side pressure. If it's very high 300+PSI or more, that would suggest either a blocked orifice, or poor airflow across the condensor. If you spray water and it drops, you need more airflow.

If the low side cuts off at 20psi or so and your high side is sub 200psi on a hot day, you just need more refrigerant. In fact, on a hot humid day, that compressor shouldn't really cycle much at all. Should hold pretty well around 40-45psi and your high side should be 250-275ish.

You should be able to maintain 40-45 degrees vent temp at idle with doors open.

But I also do think you have an airflow issue through that condenser.


Good luck, as i will be away from internet for a few days
When it was 82° outside the high side pressure was about 230 psi as the compressor was kicking on and off. This was with the windows up at night so not exactly what you’d like to see in terms of the test. Will hook up some gauges to see
 

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Depending on how much was in the evaporator and condenser you may be ok. You should check to make sure how much it came with.
 

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How are you talking the low side pressure reading if you don’t have the manifold gauge set that reads both High & Low.

I don’t understand how you can only get the low side readings right now. Are you just using the cheap little gauge on the refill hose of the cans?

lastly, did you pull a vacuum on the system before re-charhing it and how long did you pull that vacuum?
It’s necessary to pull/ boil air/moisture out
 

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Discussion Starter · #47 ·
How are you talking the low side pressure reading if you don’t have the manifold gauge set that reads both High & Low.

I don’t understand how you can only get the low side readings right now. Are you just using the cheap little gauge on the refill hose of the cans?

lastly, did you pull a vacuum on the system before re-charhing it and how long did you pull that vacuum?
It’s necessary to pull/ boil air/moisture out
Just using a cheapo gauge that goes onto the low side port to a can of Freon. I pulled a vacuum for about 2 hours
 

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Just using a cheapo gauge that goes onto the low side port to a can of Freon. I pulled a vacuum for about 2 hours
For future reference, two hours really isn’t enough time, especially if you’ve opened the system up and replaced parts and have fresh oil. Often times the oil traps air bubbles.

I Know most DIYers don’t have this sort of equipment (and I don’t blame them because it’s spendy), but I use a micron gauge and pull down to 500-1000 micron before charge. On systems that I replace parts like orifice tube and condenser, I find I have to run about 24 hours to get to that level and my pump is a big 7 CFM vacuum pump with fresh oil. Once I do that initial pull, any subsequent pull only takes 15 min or so to get down to 500 micron.

next time, I’d just run it overnight at least. My number below is a bit overkill, but overnight should be adequate unless the system is extremely saturated.
 

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Discussion Starter · #49 ·
For future reference, two hours really isn’t enough time, especially if you’ve opened the system up and replaced parts and have fresh oil. Often times the oil traps air bubbles.

I Know most DIYers don’t have this sort of equipment, but I use a micron gauge and pull down to 500-1000 micron before charge. On systems that I replace parts like orifice tube and condenser, I find I have to run at least 24 hours to get to that level and my pump is a big 7 CFM vacuum pump with fresh oil. Once I do that initial pull, any subsequent pull only takes 15 min or so to get down to 500 micron.

next time, I’d run it overnight
Wow I would’ve never know that. Most guides I’ve seen just say to pull it for about an hour and it should be sufficient. I’m gonna get some gauges on it soon to make sure the pressures are appropriate for the temperature
 

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For future reference, two hours really isn’t enough time, especially if you’ve opened the system up and replaced parts and have fresh oil. Often times the oil traps air bubbles.

I Know most DIYers don’t have this sort of equipment (and I don’t blame them because it’s spendy), but I use a micron gauge and pull down to 500-1000 micron before charge. On systems that I replace parts like orifice tube and condenser, I find I have to run about 24 hours to get to that level and my pump is a big 7 CFM vacuum pump with fresh oil. Once I do that initial pull, any subsequent pull only takes 15 min or so to get down to 500 micron.

next time, I’d just run it overnight at least. My number below is a bit overkill, but overnight should be adequate unless the system is extremely saturated.
Man, those gauges are expensive. I was going to get one since I need to pull mine down after swapping the condenser and drier. I think Ill just run it for 12 hours and call it good. The system has stayed sealed this whole time and I live in a low humidity environment so I would think 12 hours should be sufficient.
 

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I have some gauges on the car. It’s about 95° outside at the moment with 60% humidity. Low side pressure is reading 30 psi, high side sitting at 275 psi
you should be seeing 50-55 on the low side and 275-300 on the high side. I think you should add a little more refrigerant.
 
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Since your high side is on the low side of the range and the low side is low, I would add some refrigerant. If your high side was already at 300 or higher I would suspect airflow being too low to the point its causing an issue.. I believe spraying water on it will always lower the high side some as its going to pull heat of the condenser. @Mustang5L5 seems to be more experienced than me with AC so you can wait for him if you want a 2nd opinion. You arent going to need to add much more. I would think 1 or 2 ounces would probably do it.
 

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Discussion Starter · #56 ·
Since your high side is on the low side of the range and the low side is low, I would add some refrigerant. If your high side was already at 300 or higher I would suspect airflow being too low to the point its causing an issue.. I believe spraying water on it will always lower the high side some as its going to pull heat of the condenser. @Mustang5L5 seems to be more experienced than me with AC so you can wait for him if you want a 2nd opinion. You arent going to need to add much more. I would think 1 or 2 ounces would probably do it.
I got the high side to 300 and left it alone. Vent temps still aren’t where they should be so I’m gonna go ahead and add an auxiliary fan
 

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I got the high side to 300 and left it alone. Vent temps still aren’t where they should be so I’m gonna go ahead and add an auxiliary fan
What was the low side when you brought it up to 300 on the high side?
 

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It was around 33-35 psi
Sounds like you're not getting enough flow through the condenser. Your probably still low on refrigerant. Hopefully the fan helps and doesn't cause issues. If not, thinner radiator and 97 condenser would be the way to go next.
 

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Discussion Starter · #60 ·
Sounds like you're not getting enough flow through the condenser. Your probably still low on refrigerant. Hopefully the fan helps and doesn't cause issues. If not, thinner radiator and 97 condenser would be the way to go next.
That’s what I was thinking. The fan I plan on installing is a pretty stout little unit. 2200 cfm 14.5” pusher should get some air moving through the coils nicely. Definitely helped a lot garnering a better understanding of how the ac system works on a more technical level in relation to pressures, ambien temps, coolant temperature, vent temps, etc. thanks for the help guys I’ll report back with an update of how things go when I get the fan on
 
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