ac blows warm after recharge

bigbird944 · 07-13-2006, 03:17 PM

hey all,

did a 134a conversion using a kit. it was done properly there was no r12 left. no leaks the pressure yesterday was same as today. I put in the pag oil that conditions the o rings n everything for the conversion and put some freon in after that, but it still isnt blowing any cooler. im not familiar with ac so any help is apreciated. What should i check? what should i be looking at here?

Thanks in advance.

rb101 · 07-13-2006, 03:36 PM

is the clutch on the compressor locking up?

bigbird944 · 07-13-2006, 03:44 PM

how can i tell?

JonA · 07-13-2006, 03:55 PM

Did the conversion kit come with a pressure gauge? When the compressor kicks in you should see the low side pull down to 30-45 psi.

Razorback1980 · Razorback1980's Garage

If you have access to some gauges, the optimum that I shoot for is 212 on high and 30 on low. I seldom get to 212, it usually stays around 220 to 230 and stay around the 30 on the low side. If that's not cold enough, you can always add just a little more.

I have a question though...did you check this?

http://www.kronowit.com/porsches/944-heater-fix.html

When you look at the front of the compressor, you will be looking directly at the clutch. When the car is running, the part in the middle should be spinning as well as the pulley the belt goes around. If it is not and only the outside pulley is rotating, then the clutch isn't engaged and you won't get cool air because the compressor isn't pumping. Turn the a/c off and look at the front of the compressor, then turn it on and see if you can see the difference.

bigbird944 · 07-13-2006, 08:44 PM

i checked with a gauge, read 40 psi about seemed good enough so i left it, however im not sure about the clutch kicking in so il check that in the morning.

the heater fix link razorback isn't the problem i dont think, unless u sent me the wrong link im not sure but with that part when i put the freshair on (to the left) fresh air comes in and when i put it to warm (to the right) warm air comes out. so everythings peachy there.

Any pics of the compressor n things like that? i'm familiar with that at all. Sorry!

Thanks a lot for the help im feeln better already.

bigbird944 · 07-14-2006, 12:36 PM

pressure remains constant even today so no leaks, however im not sure about the clutch engaging, im not sure what to look at but when i looked at the belts all i see rotating are the betls nothin else really...

bigbird944 · 07-14-2006, 12:38 PM

where can i start troubleshooting?

Razorback1980 · Razorback1980's Garage

Okay, I'm back now...sorry it was a busy day. I'll post some pictures up here real quick to explain some things. I'll get back to you in few...

morbid · 02:37 PM

Don't know how you tested for leaks, but here's how I did with my '83 944 few years ago...

First I flushed the system with the proper solvent. Changed all o-rings in the lines. Changed oil in the compressor (I use Ester Oil in conversions from R-12 to R-134A). I also put a new receiver drier (one with R12-R134A compatible desiccants). With system closed and sealed, I put on the manometers to the low side and high side fittings. Made 15 minutes of vacuum to the system with an A/C vacuum pump (opening only the low side valve in the manometer). After vacuum, closed the low manometer valve, and wait for more than 3 minutes (with low side valve shut) to see if vacuum breaks, looking to the low (blue) gage if the needle begins to moves from -30mmHg to "0" psi. If not, the system shows no apparent leaks. Using an oil injector, I added in Oz more of ester oil witch will move with the refrigerant through the system. Then began to charge the system with R134A. With system pressurized, now you can check for leaks, if there's not a leak, the system can be full of refrigerant.

bigbird944 · 07-14-2006, 05:21 PM

Thanks a lot razorback il b lookin forward to those.

Morbid that sounds like a professional job, very well done, my ac is not leaking tho im sure of it.

Razorback1980 · Razorback1980's Garage

Not real complicated really. The outer pulley the belt rides on runs constantly and is on bearings on the case of the compressor. The clutch is an electromagnet that when it's powered by the wires, the magnet sticks to the pulley that is spinning by the belt and starts turning at the same time as the pulley. The bolt in the center of the clutch is the shaft for the compressor and the clutch is bolted to the shaft so when the clutch turns, so does the shaft and it starts pumping the refrigerant around the system. So to determine if the compressor is turning just look at the clutch or the bolt in the center and if they are turning, then the compressor is working. I am guessing that yours is because you have the right readings on the low pressure line indicating it is pumping the refrigerant around the system. So, let's assume that your clutch is engaging. You will also hear the clutch engage and disengage when you turn the a/c on and off in the car....the engine will also temporary slow down as the extra load brings the rpms down just a little and then they will rebound.

The reason I pointed you to the heater fix is that the heater and a/c blow air through the same box under the dash. If your a/c is working perfectly and cooling to the right temperature, if those clips are broken or not adjusted properly, then it's going to blow some hot air through the a/c box and heat up all that cool air the a/c system just cooled down. If you know how to pipe around the heater core, then that would tell you whether the hot water was raising the a/c temps or not. You can also test the linkages according to the web site information and make sure they are adjusted correctly.

OK, so tell me if the compressor is turning or not and we'll go from there.

Razorback1980 · Razorback1980's Garage

Not real complicated really. The outer pulley the belt rides on runs constantly and is on bearings on the case of the compressor. The clutch is an electromagnet that when it's powered by the wires, the magnet sticks to the pulley that is spinning by the belt and starts turning at the same time as the pulley. The bolt in the center of the clutch is the shaft for the compressor and the clutch is bolted to the shaft so when the clutch turns, so does the shaft and it starts pumping the refrigerant around the system. So to determine if the compressor is turning just look at the clutch or the bolt in the center and if they are turning, then the compressor is working. I am guessing that yours is because you have the right readings on the low pressure line indicating it is pumping the refrigerant around the system. So, let's assume that your clutch is engaging. You will also hear the clutch engage and disengage when you turn the a/c on and off in the car....the engine will also temporary slow down as the extra load brings the rpms down just a little and then they will rebound.

The reason I pointed you to the heater fix is that the heater and a/c blow air through the same box under the dash. If your a/c is working perfectly and cooling to the right temperature, if those clips are broken or not adjusted properly, then it's going to blow some hot air through the a/c box and heat up all that cool air the a/c system just cooled down. If you know how to pipe around the heater core, then that would tell you whether the hot water was raising the a/c temps or not. You can also test the linkages according to the web site information and make sure they are adjusted correctly.

OK, so tell me if the compressor is turning or not and we'll go from there.

morbid · 08:47 PM

Well I'm a refrigeration and A/C technician here in Puerto Rico. I didn't speak about the compressor if is running or not, cause the compressor should run (if everything is OK) with more than 60psi of refrigerant pressure in the high side. But razor is right, you should check if compressor clutch is sticking and running when you turn the a/c on. If pressure in the high side is present (more than 60psi) but clutch isn't sticking, the problem can be a faulty thermostat and/or power switch damaged. Note: It can also be some faulty or loose connection of the compressor clutch wire, relay or fuse.

Razorback1980 · Razorback1980's Garage

BigBird944, Where did you get your kit from? I am told that you probably shouldn't use PAG oil because it doesn't mix with the oil from the R12 system. You can use PAG oil but you have to take the compressor loose and drain the oil that's in it and flush the rest of the system and reassemble to use the PAG. Or at least that's what I've been told. I always just use the Ester or Caster Oil (I think that's what it was) in my conversions. But that won't keep it from getting cold...just might not lubricate as well. The kit should have told you all that and I'm just trying to find out if it did or not.

JonA · 07-15-2006, 06:34 AM

Simple test to determine if the compressor is running: Watch the low side gauge while somebody turns the a/c on. You should see a dramatic lowering of pressure on the gauge, from maybe around 75 psi to about 30. Don't worry about what the clutch looks like, unless you pull the pressure down it ain't working.......

Jon

Razorback1980 · Razorback1980's Garage

Yes, that works too. Good tip Jon...if you don't have anyone to help you then put the gauge on it and read the gauge, then start the car and check again. As Jon pointed out the reading should be higher with the car off and then go down after you start it.

bigbird944 · 07-15-2006, 09:42 AM

I did the gauge test with car off and then on and reading stayed the same, thus meaning the clutch is not engaging. I also looked at it yesterday before the gauge test and it wasnt turning. I was told that the wire might be the culprit, at least i hope so, it would seem like an easy simple fix, lol i hope.

Correction on the oil, it was the ester oil, its a new one i picked up that helps condition the o rings and is compatible with both r12 and r134a refrigerants.

Where is the wire that powers the electromagnet? would i have to remove the belly pan to access it?

Razorback1980 · Razorback1980's Garage

Yes, remove the belly pan and it should be located right next to the clutch. It's the only wire going to the compressor so you can't mistake it. The problem is that is goes through a lot of components until it reaches the compressor. The best way to find what is going wrong is just start tracing it backward. Do you have 12V at the compressor? Probably not but if you do, the problem is the compressor clutch. Next thing to check is to look for 12V at the pressure switches in the system. If you have 12V on one side but not the other (with the wires plugged in of course), then the switch is bad. If that isn't it, we'll have to find someone that has a early model car to tell us if and where any relays for the a/c system are. All this is assuming all fuses are good of course...check that first.

bigbird944 · 07-16-2006, 02:55 PM

I was looking from up top today and noticed a black wire that seems to connect to the top of the compressor, is that the wire im looking for? cuz its cut and electrical taped to a red wire that used to run up into my fuse panel under my dash. I'm not sure whats up with that wire does anyone else have this? I'd apreciate some quick responses cuz im heading over to poland tomorrow.

Thanks in advance.