A/C Question... Blowing cool...but not cold. Just vac'd and charged.
07-24-2007, 02:07 PM
#1
A/C Question... Blowing cool...but not cold. Just vac'd and charged. Hey everyone. I have the a/c system from a 99 Z28 in my 87 Trans AM. Everything... The entire set up. So...we might as well treat this as a 99 Z28 question.
When I did my swap, I replaced the drier with a new one. I also replaced the orifice tube and all seals. Everything else has about 33,xxx miles on it.
Just today, I had a vac. pulled on the system, and a leak test done. The machine found no leaks in my system. So it was charged with 1.5lbs of 134A.
With a thermometer in the center vent, Im recording a temp of about 50 degrees. I took it for a ride, and it felt like it got a tiny bit cooler, but definetly not any lower than 48.
Ide really like this system to work better. It has to fight the t-tops and the hatch glass which let a ton of sunlight in.
First, what would cause the temp of the system to not be up to par? For that matter, how far off target is my temperature? Is there anything I can check/do to make it blow colder?
I tried searching, but Im getting database errors, and I even manually went through a bunch of threads, but couldnt find anything. Any help is appreciated!
Justin
When I did my swap, I replaced the drier with a new one. I also replaced the orifice tube and all seals. Everything else has about 33,xxx miles on it.
Just today, I had a vac. pulled on the system, and a leak test done. The machine found no leaks in my system. So it was charged with 1.5lbs of 134A.
With a thermometer in the center vent, Im recording a temp of about 50 degrees. I took it for a ride, and it felt like it got a tiny bit cooler, but definetly not any lower than 48.
Ide really like this system to work better. It has to fight the t-tops and the hatch glass which let a ton of sunlight in.
First, what would cause the temp of the system to not be up to par? For that matter, how far off target is my temperature? Is there anything I can check/do to make it blow colder?
I tried searching, but Im getting database errors, and I even manually went through a bunch of threads, but couldnt find anything. Any help is appreciated!
Justin
07-24-2007, 02:22 PM
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Since its such a small system, how long did you leave the vac pump on? Did you toss a vac gauge on it and let it sit to see how many microns you pulled the system down to?
Thats the setup questions, next is; do you have a set of refrigerant gauges? If so, what are your suction and discharge pressures along with their corresponding saturation temperature? Also, what are the temperatures of the physical pipes that you are taking your readings off of.
You could be low on charge, you could still have some air in the system, your coils could be dirty, any number of things. If you have any of that information I'll do my best to help you out.
Thats the setup questions, next is; do you have a set of refrigerant gauges? If so, what are your suction and discharge pressures along with their corresponding saturation temperature? Also, what are the temperatures of the physical pipes that you are taking your readings off of.
You could be low on charge, you could still have some air in the system, your coils could be dirty, any number of things. If you have any of that information I'll do my best to help you out.
07-24-2007, 02:43 PM
#3
aint gonna like this but mine has NEVER seen a vacuum and using the same drier for 5 motor installs. Today was 86 degrees outside and my vent temp was 40 degrees driving and goes to 50 deg if it sits at a light awhile. My friend always has his done professionally and his wont go below 50 degrees....dunno why. I do mine the redneck way....shopvac to make sure all junk is out..if any...and shoot the juice to her...approx 1 and a 1/4 cans. Make sure the fan motor is clear of debris...easy to take out...mine was cluttered with leaves once like a squirrel nest. while i had the shop vac up in the fan hole, i got a lot of leaves off the evap coil (i think its what its called
07-24-2007, 03:25 PM
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The evap coil is the coil that the air blows through to go into the vehicle, thats the cold coil. The condenser coil is the hot coil.
I do A/C so of course I'm going to ask about the "right" way to do it. The fact that venting refrigerant and being ratted on can net you $50,000 and jail time also keeps me away from that. But hey if it works, it works.
I do A/C so of course I'm going to ask about the "right" way to do it. The fact that venting refrigerant and being ratted on can net you $50,000 and jail time also keeps me away from that. But hey if it works, it works.
07-24-2007, 03:32 PM
#5
did you also check that the correct amount of Oil as added to the compressor and drier ?.. usually 4-8 oz, with 50% in each of the Compressor and Drier (3 and 3 is what I ususally add to a dry system).
I don't have a 4 gen, is 1 1/2 lbs the correct charge ? seem a bit small of a charge to me. but I don't have the spec and I don't have a 4 gen f-body..
I don't have a 4 gen, is 1 1/2 lbs the correct charge ? seem a bit small of a charge to me. but I don't have the spec and I don't have a 4 gen f-body..
07-25-2007, 06:42 AM
#6
Thanks for all the feedback guys.
Alt: I took the car to a shop to have it done...and they rolled out a machine with gauges and the refidgerent loaded onto it... An automatic machine for the most part. They pulled a vac. for about 25 minutes, then it did a leak test for 15 minutes. Im not sure how far it pulled down, because the gauges looked like they were in greek to me compared to the manifolds that Ive used in the past. After the thing leak checked, it did some pressure equalizing, then loaded the system with 134. Just sitting there it got down to about 50 degrees. I took it for a ride, and while it felt like it did get al ittle cooler, it never went below 48. This temp was in the vents, not the pipes.
I dont have a set of gauges handy, but I can get ahold of some to check pressures. As for the temp of the pipes, all I can tell you is that the drier and the evaporator get really cold. Im alittle worried that my headers/engine temp is heating up my HVAC box, and the a/c air is fighting/mixing with it as it comes inside the car. The HVAC box is the only thing thats not 4th gen...so thats the only inconsistency.
I know the evap was clean, I checked it and it looked like new. The condensor is also clear and clean as far as coils go. I would imagine there is no air in the system since it had a vac. put on it, but who knows. My biggest problem was that I charged it with cans just to check my wiring and make sure the compressor would kick on. And that got it down to as cold as it is now... So I was hoping the professional job would really make it work well. 50 degrees is cool...but Ive heard of them getting colder.
bczee: Oil... Thats one area that might be a bit grey. I changed the drier, and I dumped oil from both the evap and the condensor. I also dumped as much as I could from the compressor. I measured of course... I then added in oil... I tried to account for whatever I couldnt get out of the parts, and whatever the new parts would need.
Is there anyway to determine how much oil is in there? And if there was too much, would that cause the system to not cool well enough?
The guy who charged it said the system took about 1.5lbs...and that sounded right to me. Is it possible that adding alittle bit more from a can could help boost it just alittle and get me into that 40-45 range?
Thanks again for the feedback guys! I know some of my info has holes in it...I just got the system charged yesterday. So I havent had a chance to grab the manifold set or really look into it any deeper.
Justin
Alt: I took the car to a shop to have it done...and they rolled out a machine with gauges and the refidgerent loaded onto it... An automatic machine for the most part. They pulled a vac. for about 25 minutes, then it did a leak test for 15 minutes. Im not sure how far it pulled down, because the gauges looked like they were in greek to me compared to the manifolds that Ive used in the past. After the thing leak checked, it did some pressure equalizing, then loaded the system with 134. Just sitting there it got down to about 50 degrees. I took it for a ride, and while it felt like it did get al ittle cooler, it never went below 48. This temp was in the vents, not the pipes.
I dont have a set of gauges handy, but I can get ahold of some to check pressures. As for the temp of the pipes, all I can tell you is that the drier and the evaporator get really cold. Im alittle worried that my headers/engine temp is heating up my HVAC box, and the a/c air is fighting/mixing with it as it comes inside the car. The HVAC box is the only thing thats not 4th gen...so thats the only inconsistency.
I know the evap was clean, I checked it and it looked like new. The condensor is also clear and clean as far as coils go. I would imagine there is no air in the system since it had a vac. put on it, but who knows. My biggest problem was that I charged it with cans just to check my wiring and make sure the compressor would kick on. And that got it down to as cold as it is now... So I was hoping the professional job would really make it work well. 50 degrees is cool...but Ive heard of them getting colder.
bczee: Oil... Thats one area that might be a bit grey. I changed the drier, and I dumped oil from both the evap and the condensor. I also dumped as much as I could from the compressor. I measured of course... I then added in oil... I tried to account for whatever I couldnt get out of the parts, and whatever the new parts would need.
Is there anyway to determine how much oil is in there? And if there was too much, would that cause the system to not cool well enough?
The guy who charged it said the system took about 1.5lbs...and that sounded right to me. Is it possible that adding alittle bit more from a can could help boost it just alittle and get me into that 40-45 range?
Thanks again for the feedback guys! I know some of my info has holes in it...I just got the system charged yesterday. So I havent had a chance to grab the manifold set or really look into it any deeper.
Justin
Last edited by ghettocruiser; 07-25-2007 at 06:49 AM.
07-25-2007, 08:10 AM
#7
That system calls for .68 Kg, so 1.5 lbs is real close.
Check to see if the low side line is cold and sweating all the way to the compressor. Thats the first indicator of how well the system is working. The first place it will start loosing temp (getting warmer) is the bottom of the accumulator, and then it will start getting warmer from the compressor back down the low side line.
If the temp is uniform down the low side line, all the way to the compressor, sweating right at the compressor, I would start looking at other things such as one of the doors not being closed all the way. The heater/mix door, the recirc door, etc. Or the headers heating the box is a possibility too.
Like I said, if the low side is good and cold all the way to the compressor, the refrigeration system is working as good as its gonna get.
If it has too much oil in it, the bottom of the accumulator wont be cold. Thats where most of it gets trapped. But, even if its got too much oil in it, it should work ok, unless its REALLY over filled.
PS, I wouldnt charge it any more. That wont do anything but make it worse.
Check to see if the low side line is cold and sweating all the way to the compressor. Thats the first indicator of how well the system is working. The first place it will start loosing temp (getting warmer) is the bottom of the accumulator, and then it will start getting warmer from the compressor back down the low side line.
If the temp is uniform down the low side line, all the way to the compressor, sweating right at the compressor, I would start looking at other things such as one of the doors not being closed all the way. The heater/mix door, the recirc door, etc. Or the headers heating the box is a possibility too.
Like I said, if the low side is good and cold all the way to the compressor, the refrigeration system is working as good as its gonna get.
If it has too much oil in it, the bottom of the accumulator wont be cold. Thats where most of it gets trapped. But, even if its got too much oil in it, it should work ok, unless its REALLY over filled.
PS, I wouldnt charge it any more. That wont do anything but make it worse.
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07-25-2007, 08:15 AM
#8
Ok... the brainstorming is helping me fellas!
here is another thing I didnt think of. The achetecture of my HVAC box vs. the 4th gen box. And I now think I know why the 3rd gens have a heater control valve. The 3rd gen originally had a valve that is vac. operated, and it shut off coolant flow to the heater core when the heat is off. Im sure you all know what Im talking about.
Well...since the LS1 doesnt have that, I didnt install one. So my heater core is always flowing with coolant. 180 degree coolant... Now...Im wondering if the 3rd HVAC box doesnt exactly cut off the heater core the way the LS1 cars do, and maybe Im pulling heat from the heater core even with the doors closed the way they are supposed to be.
Hmmmmmmm.... Maybe Ill disconnect the heater lines, and just run a loop off the water pump. Just to see if the temp drops before I go checking pressures and all.
The drier and evap get really cold and sweaty pretty fast. I havent followed the lines to see what all is cold and sweaty though. Thats another thing I can do. If I disconnect the heater core, and it gets colder, then I guess Ill have to plumb in a heater control valve somewhere. Or disconnect the heater core for the summer/warmer months.
Justin
here is another thing I didnt think of. The achetecture of my HVAC box vs. the 4th gen box. And I now think I know why the 3rd gens have a heater control valve. The 3rd gen originally had a valve that is vac. operated, and it shut off coolant flow to the heater core when the heat is off. Im sure you all know what Im talking about.
Well...since the LS1 doesnt have that, I didnt install one. So my heater core is always flowing with coolant. 180 degree coolant... Now...Im wondering if the 3rd HVAC box doesnt exactly cut off the heater core the way the LS1 cars do, and maybe Im pulling heat from the heater core even with the doors closed the way they are supposed to be.
Hmmmmmmm.... Maybe Ill disconnect the heater lines, and just run a loop off the water pump. Just to see if the temp drops before I go checking pressures and all.
The drier and evap get really cold and sweaty pretty fast. I havent followed the lines to see what all is cold and sweaty though. Thats another thing I can do. If I disconnect the heater core, and it gets colder, then I guess Ill have to plumb in a heater control valve somewhere. Or disconnect the heater core for the summer/warmer months.
Justin
07-25-2007, 10:49 AM
#9
Do you still have the vacumn line for the system, if so, you can use a heater control valve for the water or many use one of those electrical ones with a switch.
I am feeling the same about my system in my Chevelle, cold but not enough. I know I have to add the water control valve, the 71-71 chevelle had them right on the block, and I could use it on the LS1. I am planning on picking up a 70 chevelle one that is vacumn operated also like my 71, but mounted on the fender well. I know my friends 57, which we installed a Vintage Air setup has electrical contolled valve, you might be ableo to use either one of those setups.
I am feeling the same about my system in my Chevelle, cold but not enough. I know I have to add the water control valve, the 71-71 chevelle had them right on the block, and I could use it on the LS1. I am planning on picking up a 70 chevelle one that is vacumn operated also like my 71, but mounted on the fender well. I know my friends 57, which we installed a Vintage Air setup has electrical contolled valve, you might be ableo to use either one of those setups.
07-25-2007, 11:00 AM
#10
Well, I still have the vac line for the original heater control valve. I tried to remove it, but ended up not messing with it. Kinda glad now.
I could always just use a stock 3rd gen valve... Im pretty sure they had the 5/8" and 3/4" line just like the LS1 set up. Only thing is, Ide have to figure out how to hook the sucker up, and all that.
I would like an electric one, but I couldnt find any after some quick google searching. Any ideas on good control valves for something like this?
Justin
EDIT: Also, and correct me if Im wrong, but the LS1 motor wants to circulate those heater outlets right? So blocking them off isnt an option. So I would need a valve that allowed the coolant to circulate while the valve was closed, and then allowed to go throught he heater core when open.
Thats one thing I was never sure of... if those two ports on the water pump needed to loop to each other, or if you could really just block those off individually.
I could always just use a stock 3rd gen valve... Im pretty sure they had the 5/8" and 3/4" line just like the LS1 set up. Only thing is, Ide have to figure out how to hook the sucker up, and all that.
I would like an electric one, but I couldnt find any after some quick google searching. Any ideas on good control valves for something like this?
Justin
EDIT: Also, and correct me if Im wrong, but the LS1 motor wants to circulate those heater outlets right? So blocking them off isnt an option. So I would need a valve that allowed the coolant to circulate while the valve was closed, and then allowed to go throught he heater core when open.
Thats one thing I was never sure of... if those two ports on the water pump needed to loop to each other, or if you could really just block those off individually.
07-25-2007, 02:33 PM
#11
If you want a electrical one, check with one of the aftermarket markets of AC units. (classic air, vintage air, etc..) you might be able to buy one of there units. It is possible that you can look in the junk yards for one.
I can't answer the block or loop question, but I would like the answer too.. I have seen picture of the two port cap'd with rubber caps and clamps... so.. can we assume that it is ok to cap them.. or as you stated, they need to be circulating the coolant.??
Anyone ?
I can't answer the block or loop question, but I would like the answer too.. I have seen picture of the two port cap'd with rubber caps and clamps... so.. can we assume that it is ok to cap them.. or as you stated, they need to be circulating the coolant.??
Anyone ?
07-25-2007, 02:44 PM
#12
I did some searching... Its one of those topics that get 50% of one answer, and 50% of another answer. Some people overheat until they loop them, some run just fine with them blocked...
I stumbled across an idea that I might give a try. Someone install an "H" into the two lines down by the outlets. That means that coolant can always flow between the two ports. Then, put a vac. control valve in the hose that has pressure going to the heater core.
When the valve is closed, no coolant will pass through the core, and it should stay cooler. I assume SOME ambient heat will make it up there, but not as much as if it has coolant flowing through. With the valve closed, coolant can go though the H and loop over to the other line.
When the valve is opened, coolant can still flow between the H, but it can also circulate through the core.
After thinking about this, I kind of think the heat wont get as warm this way, but honestly, I dont drive the car much in the winter. The t-tops and all the glass on top make it like a greenhouse in the car anyway.
The wheels are turnin in my head... I know from working at autozone that there are some simple on/off vac. operated heater valves. I just gotta figure out if vac. has to open the valve, or pull it closed. Im guessing it has to open it...but I have to double check.
Justin
I stumbled across an idea that I might give a try. Someone install an "H" into the two lines down by the outlets. That means that coolant can always flow between the two ports. Then, put a vac. control valve in the hose that has pressure going to the heater core.
When the valve is closed, no coolant will pass through the core, and it should stay cooler. I assume SOME ambient heat will make it up there, but not as much as if it has coolant flowing through. With the valve closed, coolant can go though the H and loop over to the other line.
When the valve is opened, coolant can still flow between the H, but it can also circulate through the core.
After thinking about this, I kind of think the heat wont get as warm this way, but honestly, I dont drive the car much in the winter. The t-tops and all the glass on top make it like a greenhouse in the car anyway.
The wheels are turnin in my head... I know from working at autozone that there are some simple on/off vac. operated heater valves. I just gotta figure out if vac. has to open the valve, or pull it closed. Im guessing it has to open it...but I have to double check.
Justin
07-25-2007, 03:14 PM
#13
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Well if you are pulling hot engine bay temps through your evap coil and getting 50 degree air to come out, that has the possibility of being a 40 degree split, which is damn good. I am not sure about where the air is being pulled thats being pushed through the evap coil but if it is hotter than ambient air, bringing it down to 50 degrees means its running its *** off.
Typically in the field we don't want to push any colder than 45 degrees into an occupied space for cooling, and 50 isn't that far off. If you don't have a sufficient amount of air flow it can still feel warm in the car even though its pushing cold air, it just isn't pushing enough. Are you pushing a good amount of air into the cabin area or is it more like a soft breeze?
Typically in the field we don't want to push any colder than 45 degrees into an occupied space for cooling, and 50 isn't that far off. If you don't have a sufficient amount of air flow it can still feel warm in the car even though its pushing cold air, it just isn't pushing enough. Are you pushing a good amount of air into the cabin area or is it more like a soft breeze?
07-25-2007, 03:37 PM
#14
Well, the blower motor works... I cant verify that all the doors work and seal. The air that comes out is more than a breeze for sure. The far right vent is the weakest. The middle two blow good and far left blows good.
50 degrees is what Im measuring inside the middle vents with a thermometer made for measuring vent temps. I got it in a package that had a quick test gauge for checking low side pressure.
I guess my idea about it pulling in some hot air from the heater core is basically founded by the difference in the two generations' set ups. The 3rd gen shuts off hot coolant flow to the heater core when the a/c is on and temp is set to cool. The 4th gen heater core always flows coolant, but the HVAC box set up is completely different, and more complicated. SO it might do a better job of sealing/insulating the heater core from the rest of the air flow.
Im not sure how to go about check my doors for function/seal... But Im sure it involves pulling the dash apart and all, and Im not game for that right now. haha. 50 degrees is better than the 120 degrees that it is when it sits in the sun for a few minutes. So I can deal.
Im going to run the car up to operating temp, and take it for a ride with the a/c on. Ill record the temp. Then Ill let the car cool, unhook the heater core, take it for the same ride at operating temp and record the new vent temp. See if there is a difference. If there is, and its only 2 degrees, then im not going to worry about it. If it drops it to like 45 or so...I might look into a valve plan for shutting off flow to the heater core.
Justin
50 degrees is what Im measuring inside the middle vents with a thermometer made for measuring vent temps. I got it in a package that had a quick test gauge for checking low side pressure.
I guess my idea about it pulling in some hot air from the heater core is basically founded by the difference in the two generations' set ups. The 3rd gen shuts off hot coolant flow to the heater core when the a/c is on and temp is set to cool. The 4th gen heater core always flows coolant, but the HVAC box set up is completely different, and more complicated. SO it might do a better job of sealing/insulating the heater core from the rest of the air flow.
Im not sure how to go about check my doors for function/seal... But Im sure it involves pulling the dash apart and all, and Im not game for that right now. haha. 50 degrees is better than the 120 degrees that it is when it sits in the sun for a few minutes. So I can deal.
Im going to run the car up to operating temp, and take it for a ride with the a/c on. Ill record the temp. Then Ill let the car cool, unhook the heater core, take it for the same ride at operating temp and record the new vent temp. See if there is a difference. If there is, and its only 2 degrees, then im not going to worry about it. If it drops it to like 45 or so...I might look into a valve plan for shutting off flow to the heater core.
Justin
07-25-2007, 10:40 PM
#15
If your TA is anything like my 84' Z28.. you should be able to get to the box where the heater core from the inside and pull the cover off, at that point you should be able to view the door and watch it. The GM Manual has well documented testing procedures in it, Do you have one for your year/car ?
07-26-2007, 06:43 AM
#16
I dont have any real GM manuals... just the haynes BS. I didnt know there was something under the dash that was easy to open up and inspect...but I guess its possible. I know the dash has to mostly come out in order to change the heater core. But maybe there is something under there that can be taken off for inspection of the doors...
Im willing to bet that the doors get some sort of seal on them. Maybe foam seals or something. If thats the case, Im sure they will be in sub-par shape.
I gotta see what happens when I cut coolant flow to the heater core too. I found a valve that is for an 87 firebird...but its only two hook ups and a vac port. The other one listed is the one that came on my car with 3 hook ups. Im thinking the 2 hook up one is nice and simple and should work fine.
Justin
Im willing to bet that the doors get some sort of seal on them. Maybe foam seals or something. If thats the case, Im sure they will be in sub-par shape.
I gotta see what happens when I cut coolant flow to the heater core too. I found a valve that is for an 87 firebird...but its only two hook ups and a vac port. The other one listed is the one that came on my car with 3 hook ups. Im thinking the 2 hook up one is nice and simple and should work fine.
Justin
07-26-2007, 07:57 AM
#18
Originally Posted by cablebandit
check that evap coil if you can get to it...mine was covered with leaves.
Here is my evap access in case you're curious...this is before the swap was complete.
Justin
07-26-2007, 11:41 AM
#20
???? Well... in 87 it would DEFINETLY be R12. But you gotta read the very sentence of the very first post. Everything is from a 99 Z28... The entire system. From the compressor down to the bracket that holds the drier in place. So its all 134. No conversion here.
The only thing that ISNT 99 camaro..is the actual HVAC box itself. Which only carries the cold/warm air into the vents. Doesnt have anything to do with R12 or 134.
If Im not picking up heat from the heater core, or from the engine bay, then the system should perform EXACTLY as it did when it was in the 99 camaro. Ive been told a couple times that 50 degrees actually isnt too bad, but I still feel that it could be colder. I might try to mess with it today alittle.
Justin
The only thing that ISNT 99 camaro..is the actual HVAC box itself. Which only carries the cold/warm air into the vents. Doesnt have anything to do with R12 or 134.
If Im not picking up heat from the heater core, or from the engine bay, then the system should perform EXACTLY as it did when it was in the 99 camaro. Ive been told a couple times that 50 degrees actually isnt too bad, but I still feel that it could be colder. I might try to mess with it today alittle.
Justin