Year: 1988
Make: Suzuki
Model: Samurai
Engine Size: 1.3L
Refrigerant Type: 134a
Ambient Temp: 80
Pressure Low: 16-18
Pressure High: 160-165
Country of Origin: United States
I finally finished up the installation and am trying to figure out what's going on...not sure and am in need of assistance. I evacuated and charged the system with two 12 oz. cans of refrigerant about a week or so ago. The instructions called for 24 oz. Today, I checked for signs of leakage, none found. I hooked up the gauges and saw about 77 psi on the low side and 70 on the high. Ambient temperature was right around 79-80 deg F.
With the engine warming up (slightly high idle), low side was 16-18 and high side at 160-165. As the engine reached full operating temperature and the idle at about 800-900 rpm (and I assume all the components of the A/C were subject to the engine's heat), the low side was anywhere from 10-30 and the high from 165-190, with a normal low idle (a little under 1000 rpm).
When I charged up the system, I used the 2.2 x ambient temp to estimate the max. high side pressure I wanted to see. I added refrigerant until I was seeing about 185 or so based on the formula. However, the a/c does not get very cold and I suspect it may need more refrigerant.
Is it reasonable to assume that the 160-165 on the high side I saw today (before everything got fully up to operating temps) is really indicative of the state of charge of the system?
What should I do?
Thanks, Scot
Edited: Tue November 13, 2007 at 2:11 AM by ScotY
Keeping air out of your system with store bought cans is difficult for the DIYer, it sounds as though you have some AC experience, did you vacuum the system while the first unpunctured can was hooked up to your manifold gauge set so it could be serviced directly into the vacuum. Then on the second can, you have to allow some pressure in the system to bleed out throught the service hose prior to puncturing the second can, purging the air back out of the service hose.
A max of 2.7 ambient is the upper range of good pressure also for that spec. Without proper equipment I would get close (20oz) and monitor vent temps while adding freon to a max of 2.7 ambient, while not allowing air in the service hose to enter the system. The addition of more freon may need to be a very slow process, some vehicles need a drive around the block to get freon distributed around the system evenly.
If it was not performing well then I would feel around the system with my hand to see how hot or warm the pipes were getting, be carefull here. Pressure readings are very critical in diagnosis, you know this already.
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Give all the dirty details
and dont forget the LO & HI pressures
Year, Make & Model would be nice too
I followed the instructions that I found on this forum for evacuation and charging. I punctured the can, then bled the air out of the yellow hose before opening the valves on the manifold, adding the refrigerant to the vacuum. I can see how on the first and second cans how some air could enter the system, whatever air was within the manifold itself, there is no way to avoid that, I think?
Can you explain about feeling the pipes to see how warm they are? They all feel about the correct temp, the hot ones feel warm to very warm and the return line is cool.
How do you determine the ambient temp? I know that sounds like a dumb question but I have read about people putting a thermometer in the front of the car by the grill. With the engine cold, the ambient temp is about 80. With the engine hot, either running or not, that thermometer is going to read at least 85+.
Thanks, Scot
Pull the refrigerant - evacuate and recharge with 24 ounces of refrigerant per our instructions. With all the left over mounting brackets I would make sure you do not have any air leaks around the evaporator assembly. Make sure you do not have any hot water in the heater core.
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The first can let air in, next time puncture the can, crack the valve a little and use a blunt object to push gently on the center probe in the LO pressure quick disconnect to allow freon to bleed through all the hoses and the valve. On the second can do the opposite, with the manifold still hooked to the car, let the pressure in the car bleed out to the can connection through a cracked open valve, then completely tighten the can to the hose creating a leak free fit, then puncture the can.
On many Nissan Serena vans, I have had to take an hour to get all the freon in those things while using cans and be happy with the vent temps.
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Give all the dirty details
and dont forget the LO & HI pressures
Year, Make & Model would be nice too
I used the evacuation and charging instructions found here:
http://www.autoacforum.com/messageview.cfm?catid=20&threadid=7931
I understand what you are saying about letting air in. On the low side hose from the service port to the manifold valve would be vacuum, right? If I bled the yellow hose, the only air let in would be what was contained from the low side valve to the fitting where the yellow hose attaches to the manifold. I remember thinking the way I was doing it didn't seem ideal, but I assumed the procedure was spelled out so it was good enough.
Would just that little bit of air cause problems?
What is the best way to get the refrigerant out so I can vacuum and try again?
How do you get ALL the refrigerant out of the can? Do you just let the car run until it's totally empty? I gave up after a while and just put in whatever would go within about 10 minutes or so.
Is there any possibility that my system is undercharged? I used two 12 oz. cans (the instructions called for 24 oz. total) but I know for a fact that I did not get in the entire contents of both of those cans.
2.2 times ambient is the lower end of the good spectrum and 10 ~ 30 PSI LO side is still ok, even a bit LO down near 10 PSI. Without proper equipment, its all an experiment, I service by vent temps, pressures and hand feel around the system components on R12 systems, I do not have a machine for R12 and drop ins are legal as well as the primary service gas in Japan.
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Give all the dirty details
and dont forget the LO & HI pressures
Year, Make & Model would be nice too
Need to remember folks this an is aftermarket system. OEM pressure readings are not going to work in this case. You may very well see a 15 PSI on the low side in a lower ambient. How much refrigerant was lost during charging?
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I have been running the system and watching the gauges, trying to get a feel for what is going on. I put in a little more refrigerant today, don't know exactly how much as I have no way to measure it. It seems that the hotter the engine compartment gets, the higher the high side gets, on average. For example, when the engine compartment is relatively cool, the high side fluctuates between 150-170 or so. After the engine is up to temp, the readings are about 160-190. When the engine compartment gets real hot (idling stationary for 20 minutes or longer), the high side fluctuates between about 170-210. Now I think maybe I have a little too much in there.
I don't know how much was originally lost from the two cans. Whatever was in the hoses plus a little at the end of each can was lost. I suppose I could start all over from scratch but I have no way to recover the refrigerant.
What are the vent temperatures are you getting. Also are these temps with a completely enclosed samurai or with the rag top?
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How is the cooling now? You don't want to over fill, but you did lose a couple ounces in the hoses and switching cans. Make sure your fan(s) are operating properly, and the inlet and outlet are both cold around the same temp. I don't use cans but just resist the urge to add to much. I think you're right in the ballpark now and if your cooling is good, and both lines (after expansion device, and suction line right up to the compressor ) are both cold, I'd leave it alone...Unless you want to have a shop evac/recharge with the exact amount??
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Chick
Email: Chick
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Freedoms just another word for nothing left to lose
The inlet and outlet of the evap should be the same temp, if it's warmer coming out, you may be a few ounces low..Vent temps will drop with the doors closed, fan on lower speed, max air, and make sure the aftermarket fan is blowing in the right direction when it's on..If you also have an engine fan with fan clutch, might want to change the clutch? Or did you get one in the kit?? .Hope this helps..
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Chick
Email: Chick
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Freedoms just another word for nothing left to lose
Finally got some new data today! Made no changes to anything since the last time. Did not replace the fan clutch because they're really expensive at $130!!!
It was cooler today at 76F ambient temps. I measured the low side at 77 and the high at 70 before turning the a/c on. Warmed up the engine until the idle dropped to just under 1000 rpm. Then turned the compressor on, the engine was idling at about 800 rpm according to the dash tach and at 760 rpm according to an optical tach measuring the engine cooling fan. Not sure which one is the correct number. The fan clutch appears to be working fine, at least at an idle. The clutch gets stiffer as the engine gets hot and the rpm is similar.
Turning on the a/c with the blower on high, one door open, recirc air on, heater disabled, run for a few minutes and took this reading:
Low 22
High 160
After 5 minutes:
Low 20-28
High 165-180
Vent temp 52F
Blower to low, door closed, 5 minutes later:
Low 10-20
High 160-165
Vent temp 46-48F
Then the clutch turned off...
It turned back on when the settings were:
Low 40
High 120
So, it looks like I have about 30 degrees of cooling at most. I guess this is about right? I tried to take temp readings on the condenser, it was tough and I doubt the accuracy of them, but for the most part inlet was roughly 125F and outlet at about 10 degrees lower. I forgot what Chick had asked about so didn't check the evaporator inlet and outlet fittings for their temperatures.
Edited: Thu November 29, 2007 at 8:09 PM by ScotY
You have to do that...only way to know if fully charged...
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Chick
Email: Chick
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Freedoms just another word for nothing left to lose
Get temps at 1500 RPM and doors closed.
I still think the evap is pulling air around the intake and not through the core itself. Or you have a hot water issue with the heater core. Pressures are not out of line at that ambient. Anyone trying to assist needs to know this is an after market system with a expansion valve and true PF condenser. Did you attach the copper tube in the expansion valve to the large copper line on the evaporator? Also was it wrapped with the black tar/tape that was provided?
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Hi Tim,
The copper tube/bulb is clipped onto the evaporator outlet tube, then wrapped with some of that black tar stuff. Will check temps at 1500 rpm and get right back to you...
Do it by feel, infrared thermometers aren't accurate with the heat all around..To the touch they should feel the same temp..The suction line should be cold all the back to the compressor also..
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Chick
Email: Chick
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Freedoms just another word for nothing left to lose
If they are both cold, and the suction line is cold up to the compressor, you can rule out the charge, it's full..No you will have to find where the warm air is blending in...As Tim stated..
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Chick
Email: Chick
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Freedoms just another word for nothing left to lose
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