Alright, summer heat sucks and I'm putting the a/c back into my 240sx, but I've got a few questions...
1) I swapped in a 1995 motor into the 90 chassis. A/C is completely empty, so I know I need/should/is reccomended to change the drier and expansion valve and O-rings because the system was opened. I know where I should be looking for the expansion valve, but I'm not seeing it. Where is it located?
"took out the glove box of the 90 Q in search of the a/c expansion valve.Does anyone know where it is..... and can you get to it and replace it?" *from a 90 Q thread.
2) When I retrofit and convert the system I should only use about 85% (32oz) of r134 and small can of Ester oil?
"i read in most aftermarket recharging/retrofitting kits that u should use only 85% of the stated r12 spec to refill the system (if you're not going to change any components) that way, you won't blow the seals"All I did was have all the parts flushed, ordered new expansion valve, receiver/drier, and rubber seals, and threw it all back together and charged with ~32 ounces of R134a and a small can of Ester oil. Works great" *another a/c thread
The rest I can manage I believe, I've done a lot of reading at the library in various manuals and internet sources. I've got a pretty good feel of what needs to be done, I just need to find that expansion valve in its definite location and be 100% sure of everything before I go ahead with the procedure.
Thanks in advance for the help, and if theres anything else of importance you think I should know, please share!!
'90 240sx expansion valve location, and a ?
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benemorius
- Posts: 1937
- Joined: Tue Jun 08, 2004 5:39 pm
- Car: s13, s13, eg, e36
Re: (navysnail)
I plan to do a writeup on the 240 a/c system before too long, but since that is still in the future here is the bit you need:
Quote »'90 240 expansion valve replacement:
-remove glovebox - open it and remove two 10mm bolts at the top (top as in where the latch hook is) and one 10mm bolt at the bottom right and one 8mm bolt at the bottom left
-identify the evaporator box (It's the big black box taking up the entire left half of the hole made by the glovebox removal. At it's bottom center you will see the condensation tube exiting through the firewall/floorpan)
-remove two 10mm bolts at the top
-remove one 10mm bolt and one 10mm nut at the bottom (on either side of the condensation tube)
-remove 10mm bolt on the left side (just barely hidden by the dash - not hard to reach)
-remove one 10mm bolt on the right
-detach two wiring harnesses from evaporator box and just leave them hanging
-STOP - you think the box is now free to drop but it isn't...
-pop the hood and go out and look right by where the throttlebody would be if you hadn't swapped to the dohc (it's right on the opposite side of the firewall to the evaporator box)
-locate the two pipes side by side
-disconnect each pipe using two wrenches so as not to bend or twist anything
-now go back inside and try to pull the evaporator box back and slightly down (I may have forgotten about some bolts or you may have some that I did not)
-once the box is free, examine it and notice how it is divided into two halves
-proceed to remove all the screws that hold the two halves together
-there are also two metal clips that must be removed
-once the two halves are free, separate them - take care not to bend or otherwise damage the fins on the evaporator core inside the box
-the expansion valve is the bulge wrapped in black insulating tape - carefully unrap the tape around the valve as it is easy to bend fins while doing this
-now find the capillary tube which is also wrapped in tape and unwap it (it has a tiny brass tube running from it to the expansion valve)
-you can now disconnect and remove the expansion valve - be sure to use two wrenches when applicable so as not to bend or twist pipes - and again do not damage any fins
-Reinstallation should be pretty straightforward. The only noteworth things I can think of are:
-be sure to replace any o-rings with new green ones coated in new refrigeration oil
-as you reinstall the evaporator box, be sure the condensation tube goes back into it's hole through the firewall/floorpan or you will wind up with water dripping down onto your passenger's feet
-once again - make sure you use two wrenches when applicable so as not to bend or twist any pipes
-any time the system has been open to the environment for more than a few minutes, you MUST REPLACE THE RECEIVER/DRYER as it can only hold so much moisture before it becomes useless. Now, moisture is less deadly in a 134a system as it does not combine to produce acid as it does with r12, but it does still cause other problems. Even a leak is considered too much exposure if all the refrigerant has escaped and nothing is left to keep the air and moisture from coming back inside through that leak.[/quote]%85 r12 capacity is generally accepted, I suppose. However, the proper way to do it since we don't have a manufacturer telling us exactly what the r134a capacity is would be to start with an amount that you are 100% sure will be too little. Then, stick a thermometer in the center vent with the blower fan on high and periodically add small amounts of refrigerant while watching the temperature. It should gradually fall and then stop and begin to go back up. When you see it going back up, remove some refrigerant until it goes back down to where it's lowest point was.
You also need to make sure you vacuum evacuate the system before charging it with refrigerant. This is almost definately the number one mistake in DIY a/c jobs. You should be able to find plenty of info on the net concerning this. Hopefully you already have a decent air compressor. If this is the case, run down to harbor freight and pick up a $15 venturi design vacuum pump. This step is not optional. If you don't do it you may as well forget the whole thing. As a last resort, you can at least take it to a shop and have them do the evacuation.
Manifold gauges are riding the fence between necessary and not. You should be able to find some for only $50, and I recommend you do. However, technically you can probably get the a/c working without them. Again though, please do yourself the favor and get some. You'll at least have the comfort of doing it the right way.
I can't think of anything else, but I must say that while it is true that a/c can be DIY, there are many important things to know about it that you simply wouldn't know unless you were told. Unless you are truly familiar with a/c systems, I recommend you post your final planned procedure here before actually carrying it out. Many things can leave your a/c system nonfunctional; some things can leave it in peaces; some things can even leave you in peaces.
EDIT: wewt! I haven't been here in weeks and I think I just made up for all that time in a single post.
EDITED so it actually makes sense: "you MUST REPLACE IT" became "you MUST REPLACE THE RECEIVER/DRYER"
Modified by benemorius at 9:19 PM 7/25/2005
Quote »'90 240 expansion valve replacement:
-remove glovebox - open it and remove two 10mm bolts at the top (top as in where the latch hook is) and one 10mm bolt at the bottom right and one 8mm bolt at the bottom left
-identify the evaporator box (It's the big black box taking up the entire left half of the hole made by the glovebox removal. At it's bottom center you will see the condensation tube exiting through the firewall/floorpan)
-remove two 10mm bolts at the top
-remove one 10mm bolt and one 10mm nut at the bottom (on either side of the condensation tube)
-remove 10mm bolt on the left side (just barely hidden by the dash - not hard to reach)
-remove one 10mm bolt on the right
-detach two wiring harnesses from evaporator box and just leave them hanging
-STOP - you think the box is now free to drop but it isn't...
-pop the hood and go out and look right by where the throttlebody would be if you hadn't swapped to the dohc (it's right on the opposite side of the firewall to the evaporator box)
-locate the two pipes side by side
-disconnect each pipe using two wrenches so as not to bend or twist anything
-now go back inside and try to pull the evaporator box back and slightly down (I may have forgotten about some bolts or you may have some that I did not)
-once the box is free, examine it and notice how it is divided into two halves
-proceed to remove all the screws that hold the two halves together
-there are also two metal clips that must be removed
-once the two halves are free, separate them - take care not to bend or otherwise damage the fins on the evaporator core inside the box
-the expansion valve is the bulge wrapped in black insulating tape - carefully unrap the tape around the valve as it is easy to bend fins while doing this
-now find the capillary tube which is also wrapped in tape and unwap it (it has a tiny brass tube running from it to the expansion valve)
-you can now disconnect and remove the expansion valve - be sure to use two wrenches when applicable so as not to bend or twist pipes - and again do not damage any fins
-Reinstallation should be pretty straightforward. The only noteworth things I can think of are:
-be sure to replace any o-rings with new green ones coated in new refrigeration oil
-as you reinstall the evaporator box, be sure the condensation tube goes back into it's hole through the firewall/floorpan or you will wind up with water dripping down onto your passenger's feet
-once again - make sure you use two wrenches when applicable so as not to bend or twist any pipes
-any time the system has been open to the environment for more than a few minutes, you MUST REPLACE THE RECEIVER/DRYER as it can only hold so much moisture before it becomes useless. Now, moisture is less deadly in a 134a system as it does not combine to produce acid as it does with r12, but it does still cause other problems. Even a leak is considered too much exposure if all the refrigerant has escaped and nothing is left to keep the air and moisture from coming back inside through that leak.[/quote]%85 r12 capacity is generally accepted, I suppose. However, the proper way to do it since we don't have a manufacturer telling us exactly what the r134a capacity is would be to start with an amount that you are 100% sure will be too little. Then, stick a thermometer in the center vent with the blower fan on high and periodically add small amounts of refrigerant while watching the temperature. It should gradually fall and then stop and begin to go back up. When you see it going back up, remove some refrigerant until it goes back down to where it's lowest point was.
You also need to make sure you vacuum evacuate the system before charging it with refrigerant. This is almost definately the number one mistake in DIY a/c jobs. You should be able to find plenty of info on the net concerning this. Hopefully you already have a decent air compressor. If this is the case, run down to harbor freight and pick up a $15 venturi design vacuum pump. This step is not optional. If you don't do it you may as well forget the whole thing. As a last resort, you can at least take it to a shop and have them do the evacuation.
Manifold gauges are riding the fence between necessary and not. You should be able to find some for only $50, and I recommend you do. However, technically you can probably get the a/c working without them. Again though, please do yourself the favor and get some. You'll at least have the comfort of doing it the right way.
I can't think of anything else, but I must say that while it is true that a/c can be DIY, there are many important things to know about it that you simply wouldn't know unless you were told. Unless you are truly familiar with a/c systems, I recommend you post your final planned procedure here before actually carrying it out. Many things can leave your a/c system nonfunctional; some things can leave it in peaces; some things can even leave you in peaces.
EDIT: wewt! I haven't been here in weeks and I think I just made up for all that time in a single post.
EDITED so it actually makes sense: "you MUST REPLACE IT" became "you MUST REPLACE THE RECEIVER/DRYER"
Modified by benemorius at 9:19 PM 7/25/2005