I want to "modernize" my A/C system - 99 Z28
07-05-2017, 08:25 AM
#1
I want to "modernize" my A/C system - 99 Z28 I have a slow leak somewhere in the system that is costing me approximately 2 cans every year. Even at full charge however I have to run the blower at the highest setting during anything above 85 degrees to keep the car anywhere near comfortable. This is the only car I have this problem with, in short.. the A/C system in this car just isn't really that strong.
I'm sure with the right time and money, fabrication can be done to upgrade the weaker links of our A/C system but the thing is, I don't know what those weak links are. Could we benefit from using a more modern A/C Compressor? (Maybe one out of a 5th or 6th Gen or a truck motor even if fabrication was necessary to get it to work?)
Any other parts you can think of? I don't think the condenser is really an issue, not sure on the accumulator but I'm leaning toward no.
I'm sure with the right time and money, fabrication can be done to upgrade the weaker links of our A/C system but the thing is, I don't know what those weak links are. Could we benefit from using a more modern A/C Compressor? (Maybe one out of a 5th or 6th Gen or a truck motor even if fabrication was necessary to get it to work?)
Any other parts you can think of? I don't think the condenser is really an issue, not sure on the accumulator but I'm leaning toward no.
07-05-2017, 09:09 AM
#2
07-05-2017, 01:53 PM
#4
TECH Addict
Always replace the dryer if you crack the system open.. Moisture in very small amounts really dorks up the efficiency of AC.. And if its never been swapped then its likely time.. 
07-05-2017, 04:42 PM
#5
the 98-02 f-body has the V7 type/style of compressor. the 93-97 f-body had the H6 compressor. biggest problem of the H6 compressor was they were prone to leaking from the oring between the two case halves, many will argue it was a design problem.
but either one of those compressors and most any car AC compressor can pump quite a bit of refrigerant. It is dependent on rpm, and "at highway speeds" it's often said the compressors can pump enough to accommodate more than 3 tons of cooling. A compressor from a 2017 vehicle is not going to offer anything a functioning compressor from 1995 can't already do.
The condenser is very important, and will limit the cooling performance of the system if it's not big enough to expel the heat. Same goes for the evaporator in the dash, and the blower moving enough air across your evaporator. You want 300-500 cfm of air for every 1 ton of cooling (rule of thumb for residential central air). So any problem you may have is not with the design or capability of your compressor, at most your compressor is worn and needs to be replaced.
as far as i know the 4gen f-body have a parallel-flow style condenser from the factory, unless you somehow have a serpentine style condenser there's nothing else you can do other than increase the size of condenser, increase airflow through it, and/or decrease air temp flowing through it. and don't overlook dirt and corrosion on the fins of it which can reduce it's ability to expel heat. There is AC condenser/evaporator fin cleaner (CRC foaming coil cleaner for example). not sure how well it would work on a car with condenser mounted in front of radiator, ideally you want complete access to get at both sides of the condenser coils/fins. Same for the evaporator, which unfortunately is mounted inside the dash and not accessible. If you drive in dusty conditions and often had the heat or AC on then you are likely taking a performance hit because your evaporator coils are dirty.
other common problem on cars is the hvac head unit in dash is either not controlling the blend doors inside the dash or the doors are broken/stuck and your not getting 100% air over the evaporator to be cooled... you have either a mix of uncooled outside air or heated air from the heater core.
but either one of those compressors and most any car AC compressor can pump quite a bit of refrigerant. It is dependent on rpm, and "at highway speeds" it's often said the compressors can pump enough to accommodate more than 3 tons of cooling. A compressor from a 2017 vehicle is not going to offer anything a functioning compressor from 1995 can't already do.
The condenser is very important, and will limit the cooling performance of the system if it's not big enough to expel the heat. Same goes for the evaporator in the dash, and the blower moving enough air across your evaporator. You want 300-500 cfm of air for every 1 ton of cooling (rule of thumb for residential central air). So any problem you may have is not with the design or capability of your compressor, at most your compressor is worn and needs to be replaced.
as far as i know the 4gen f-body have a parallel-flow style condenser from the factory, unless you somehow have a serpentine style condenser there's nothing else you can do other than increase the size of condenser, increase airflow through it, and/or decrease air temp flowing through it. and don't overlook dirt and corrosion on the fins of it which can reduce it's ability to expel heat. There is AC condenser/evaporator fin cleaner (CRC foaming coil cleaner for example). not sure how well it would work on a car with condenser mounted in front of radiator, ideally you want complete access to get at both sides of the condenser coils/fins. Same for the evaporator, which unfortunately is mounted inside the dash and not accessible. If you drive in dusty conditions and often had the heat or AC on then you are likely taking a performance hit because your evaporator coils are dirty.
other common problem on cars is the hvac head unit in dash is either not controlling the blend doors inside the dash or the doors are broken/stuck and your not getting 100% air over the evaporator to be cooled... you have either a mix of uncooled outside air or heated air from the heater core.
07-12-2017, 04:08 PM
#6
the 98-02 f-body has the V7 type/style of compressor. the 93-97 f-body had the H6 compressor. biggest problem of the H6 compressor was they were prone to leaking from the oring between the two case halves, many will argue it was a design problem.
but either one of those compressors and most any car AC compressor can pump quite a bit of refrigerant. It is dependent on rpm, and "at highway speeds" it's often said the compressors can pump enough to accommodate more than 3 tons of cooling. A compressor from a 2017 vehicle is not going to offer anything a functioning compressor from 1995 can't already do.
The condenser is very important, and will limit the cooling performance of the system if it's not big enough to expel the heat. Same goes for the evaporator in the dash, and the blower moving enough air across your evaporator. You want 300-500 cfm of air for every 1 ton of cooling (rule of thumb for residential central air). So any problem you may have is not with the design or capability of your compressor, at most your compressor is worn and needs to be replaced.
as far as i know the 4gen f-body have a parallel-flow style condenser from the factory, unless you somehow have a serpentine style condenser there's nothing else you can do other than increase the size of condenser, increase airflow through it, and/or decrease air temp flowing through it. and don't overlook dirt and corrosion on the fins of it which can reduce it's ability to expel heat. There is AC condenser/evaporator fin cleaner (CRC foaming coil cleaner for example). not sure how well it would work on a car with condenser mounted in front of radiator, ideally you want complete access to get at both sides of the condenser coils/fins. Same for the evaporator, which unfortunately is mounted inside the dash and not accessible. If you drive in dusty conditions and often had the heat or AC on then you are likely taking a performance hit because your evaporator coils are dirty.
other common problem on cars is the hvac head unit in dash is either not controlling the blend doors inside the dash or the doors are broken/stuck and your not getting 100% air over the evaporator to be cooled... you have either a mix of uncooled outside air or heated air from the heater core.
but either one of those compressors and most any car AC compressor can pump quite a bit of refrigerant. It is dependent on rpm, and "at highway speeds" it's often said the compressors can pump enough to accommodate more than 3 tons of cooling. A compressor from a 2017 vehicle is not going to offer anything a functioning compressor from 1995 can't already do.
The condenser is very important, and will limit the cooling performance of the system if it's not big enough to expel the heat. Same goes for the evaporator in the dash, and the blower moving enough air across your evaporator. You want 300-500 cfm of air for every 1 ton of cooling (rule of thumb for residential central air). So any problem you may have is not with the design or capability of your compressor, at most your compressor is worn and needs to be replaced.
as far as i know the 4gen f-body have a parallel-flow style condenser from the factory, unless you somehow have a serpentine style condenser there's nothing else you can do other than increase the size of condenser, increase airflow through it, and/or decrease air temp flowing through it. and don't overlook dirt and corrosion on the fins of it which can reduce it's ability to expel heat. There is AC condenser/evaporator fin cleaner (CRC foaming coil cleaner for example). not sure how well it would work on a car with condenser mounted in front of radiator, ideally you want complete access to get at both sides of the condenser coils/fins. Same for the evaporator, which unfortunately is mounted inside the dash and not accessible. If you drive in dusty conditions and often had the heat or AC on then you are likely taking a performance hit because your evaporator coils are dirty.
other common problem on cars is the hvac head unit in dash is either not controlling the blend doors inside the dash or the doors are broken/stuck and your not getting 100% air over the evaporator to be cooled... you have either a mix of uncooled outside air or heated air from the heater core.
I tried to recharge my system yesterday - AC on MAX engine running and could not get filled past 35 PSI regardless of how many cans I threw at it. Another thing is.. it's not getting very cold at all. As in I am having to run it on MAX all the time highway or street just to keep things bearable (not even cold, but just tolerable) Also... running it at MAX only on the Highway keeps causing my temperature gauge to climb to redline. THIS DOES NOT HAPPEN ON THE STREET OR AT IDLE, stays at 210. It takes about 15 minutes of highway driving but the gauge will redline and I have to turn off the AC or risk overheating. With the AC off completely it doesn't go above 210. I have run into this issue off and on ever since I owned the car and at first thought it was a faulty temperature sensor (car doesn't behave any differently at redline)
I replaced the temperature sensor twice and it SEEMS like right after I replace it the issue goes away. It has to be 85 degrees outside or hotter for this issue to occur as well otherwise I can run the AC indefinitely and it won't overheat. I have a PLX device in my car and can read real-time OBD scans and the temperature is climbing as high as 250* per the OBD readings. I am however only using the cheapest Advanced Auto parts temp sensor so I don't know how reliable they are.
I have a transmission cooler mounted 2-3" in front of my condensor. I don't know if this is causing the issue or not.
What is your opinion?
Edit: Adding to this, when I get an opportunity, Im going to take it to a self-car wash, disassemble the intake shrowd and blast the radiator and condensor and hopefully that will reslove my issue.
Last edited by Need4Camaro; 07-12-2017 at 05:10 PM.
07-13-2017, 09:27 AM
#7
running AC causes engine coolant gauge to redline (THIS DOES NOT HAPPEN ON THE STREET OR AT IDLE........
the AC evaporator coil in your dash cools the air blown into cabin; that heat from the air is carried by the refrigerant back to compressor then pumped around and must be expelled by the condenser- the AC radiator in front of your engine coolant radiator, which you say also has a transmission cooler in front of it. Not knowing your car and if engine bay has been modified or what work has been done on car, it's not uncommon to f up the airflow that is supposed to happen through the radiator(s) and then around the engine and exit out from under the car. when not moving, the radiator fans can move that heated air and it will for the most part escape out from under the car and nothing will overheat. When at highway speeds, you can have significant pressure differentials between the outside, underside, and front of the car. Lower your car, add a bunch of **** or even remove **** from engine bay can disrupt and cause an airflow problem where air just hits the radiator and doesn't flow through and out from under car. If you remove the front plastic air dam/director thing from underneath the radiator that can definitely cause your highway only overheat problem.
regarding charging your ac and not getting past 35psi, that gives me the impression you might not know what you are doing- you are using only a store bought can with a gauge on it? you are looking only at low side pressure, which when compressor is running will never (should never) go above ~55psi. You need to look at the high side pressure, which is probably over 300 psi now because of the system being overcharged from could not get filled past 35 PSI regardless of how many cans I threw at it. you need at least an "ac manifold gauge set" to look at both high side & low side pressures, and check out some youtube about do it yourself auto ac. my recommendation would be to not use the AC because you will destroy your compressor and a $100-200 fix will now cost you over $1000, find a local AC place and ask them if they can do a quick evac and refill.
the AC evaporator coil in your dash cools the air blown into cabin; that heat from the air is carried by the refrigerant back to compressor then pumped around and must be expelled by the condenser- the AC radiator in front of your engine coolant radiator, which you say also has a transmission cooler in front of it. Not knowing your car and if engine bay has been modified or what work has been done on car, it's not uncommon to f up the airflow that is supposed to happen through the radiator(s) and then around the engine and exit out from under the car. when not moving, the radiator fans can move that heated air and it will for the most part escape out from under the car and nothing will overheat. When at highway speeds, you can have significant pressure differentials between the outside, underside, and front of the car. Lower your car, add a bunch of **** or even remove **** from engine bay can disrupt and cause an airflow problem where air just hits the radiator and doesn't flow through and out from under car. If you remove the front plastic air dam/director thing from underneath the radiator that can definitely cause your highway only overheat problem.
regarding charging your ac and not getting past 35psi, that gives me the impression you might not know what you are doing- you are using only a store bought can with a gauge on it? you are looking only at low side pressure, which when compressor is running will never (should never) go above ~55psi. You need to look at the high side pressure, which is probably over 300 psi now because of the system being overcharged from could not get filled past 35 PSI regardless of how many cans I threw at it. you need at least an "ac manifold gauge set" to look at both high side & low side pressures, and check out some youtube about do it yourself auto ac. my recommendation would be to not use the AC because you will destroy your compressor and a $100-200 fix will now cost you over $1000, find a local AC place and ask them if they can do a quick evac and refill.
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07-13-2017, 04:37 PM
#8
running AC causes engine coolant gauge to redline (THIS DOES NOT HAPPEN ON THE STREET OR AT IDLE........
the AC evaporator coil in your dash cools the air blown into cabin; that heat from the air is carried by the refrigerant back to compressor then pumped around and must be expelled by the condenser- the AC radiator in front of your engine coolant radiator, which you say also has a transmission cooler in front of it. Not knowing your car and if engine bay has been modified or what work has been done on car, it's not uncommon to f up the airflow that is supposed to happen through the radiator(s) and then around the engine and exit out from under the car. when not moving, the radiator fans can move that heated air and it will for the most part escape out from under the car and nothing will overheat. When at highway speeds, you can have significant pressure differentials between the outside, underside, and front of the car. Lower your car, add a bunch of **** or even remove **** from engine bay can disrupt and cause an airflow problem where air just hits the radiator and doesn't flow through and out from under car. If you remove the front plastic air dam/director thing from underneath the radiator that can definitely cause your highway only overheat problem.
regarding charging your ac and not getting past 35psi, that gives me the impression you might not know what you are doing- you are using only a store bought can with a gauge on it? you are looking only at low side pressure, which when compressor is running will never (should never) go above ~55psi. You need to look at the high side pressure, which is probably over 300 psi now because of the system being overcharged from could not get filled past 35 PSI regardless of how many cans I threw at it. you need at least an "ac manifold gauge set" to look at both high side & low side pressures, and check out some youtube about do it yourself auto ac. my recommendation would be to not use the AC because you will destroy your compressor and a $100-200 fix will now cost you over $1000, find a local AC place and ask them if they can do a quick evac and refill.
the AC evaporator coil in your dash cools the air blown into cabin; that heat from the air is carried by the refrigerant back to compressor then pumped around and must be expelled by the condenser- the AC radiator in front of your engine coolant radiator, which you say also has a transmission cooler in front of it. Not knowing your car and if engine bay has been modified or what work has been done on car, it's not uncommon to f up the airflow that is supposed to happen through the radiator(s) and then around the engine and exit out from under the car. when not moving, the radiator fans can move that heated air and it will for the most part escape out from under the car and nothing will overheat. When at highway speeds, you can have significant pressure differentials between the outside, underside, and front of the car. Lower your car, add a bunch of **** or even remove **** from engine bay can disrupt and cause an airflow problem where air just hits the radiator and doesn't flow through and out from under car. If you remove the front plastic air dam/director thing from underneath the radiator that can definitely cause your highway only overheat problem.
regarding charging your ac and not getting past 35psi, that gives me the impression you might not know what you are doing- you are using only a store bought can with a gauge on it? you are looking only at low side pressure, which when compressor is running will never (should never) go above ~55psi. You need to look at the high side pressure, which is probably over 300 psi now because of the system being overcharged from could not get filled past 35 PSI regardless of how many cans I threw at it. you need at least an "ac manifold gauge set" to look at both high side & low side pressures, and check out some youtube about do it yourself auto ac. my recommendation would be to not use the AC because you will destroy your compressor and a $100-200 fix will now cost you over $1000, find a local AC place and ask them if they can do a quick evac and refill.
Verdict is, I'll just let an A/C shop tell me how many thousands of dollars I'm going to spend to fix it some time later this year as long as its no longer in danger of overheating at this time, if its going to overheat though then I'm just going to park it after I get home again and address it when I have my motor rebuilt.
07-14-2017, 09:51 PM
#9
dude just don't run the AC until u have a shop that can do AC properly, it's most likely overcharged and the more u run it now the quicker it will wear out the compressor. All that needs to be done is have a shop evac the system, ask them to pull the orifice tube and check for sludge or metal on its screen. If there is then u will need extra work done depending on severity. But if it's clean then it's a simple evac, and recharge of the correct amount of r134a. I guarantee you right now the overcharging of your ac is the majority of your problem and u specifically need to fix this first. The ac system is supposed to have 1.5 lbs or 24 ounces of r134a, and being over or under charged by more than an ounce will cause problems. Sometimes u can find a place to do what I said for less than $100, a place advertising free ac checkup/tune-up.
07-16-2017, 11:40 AM
#10
dude just don't run the AC until u have a shop that can do AC properly, it's most likely overcharged and the more u run it now the quicker it will wear out the compressor. All that needs to be done is have a shop evac the system, ask them to pull the orifice tube and check for sludge or metal on its screen. If there is then u will need extra work done depending on severity. But if it's clean then it's a simple evac, and recharge of the correct amount of r134a. I guarantee you right now the overcharging of your ac is the majority of your problem and u specifically need to fix this first. The ac system is supposed to have 1.5 lbs or 24 ounces of r134a, and being over or under charged by more than an ounce will cause problems. Sometimes u can find a place to do what I said for less than $100, a place advertising free ac checkup/tune-up.
Ok. I'll check into it.
07-19-2017, 06:38 PM
#12
Odd thing is, even at 250, the car still drove perfectly normal.
07-19-2017, 07:02 PM
#13
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I promise its still partially clogged. Ive cleaned them, and lots of oil coolers and radiators on 4wheelers, and you cant clean them properly without taking them out. Perfect example below, this was a cooler i sprayed the **** out of with water on the front, then ended up removing it and flipped it over. WTF?? Front side looked perfectly clean.
07-19-2017, 11:08 PM
#14
I promise its still partially clogged. Ive cleaned them, and lots of oil coolers and radiators on 4wheelers, and you cant clean them properly without taking them out. Perfect example below, this was a cooler i sprayed the **** out of with water on the front, then ended up removing it and flipped it over. WTF?? Front side looked perfectly clean.
yeah, that will definately cause overheating issues.
I'll probably just replace the condenser, it has over 200k miles on it anyway.