a/c Freon pressure specs
 

I was reading about a month ago in this forum about a/c problems and ran across a link that had the bmw pressure specs for the x5 mine is a (2001 4.4) I would like to know what the specs are for the freon (high side and low side or link to them )
In my search I have read also that I should use R134-a if I should need to add some and a maximum of 1lb I would like to have comfirmation on these specs also
Thnx in advance:thumbup:

Wish I could tell you what the pressures are for the High and Low side. But I will confirm that you need to use R-134a. I congratulate you on your recognizing that you need some thing to monitor the pressues on the high and low sides before adding anything. That being said, I believe the system holds a total of one pound. If your system is currently running, and cooling some. Dont add one pound. You will over presurize it. Bad news.

It seems from other posts that recharging the system r134 can be a somewhat a DIYer project. Firstly, is this an accurate assumption? Secondly, if so, does anyone have some instructions on doing so. Is there something you can buy to monitor the amount of pressure in the system and to determine how much r134 is needed.

I am a pretty handy guy, but have never attempted something like this myself, and was wondering if I would be getting over my head pretty quickly.

I have already replaced the FSR, as outlined on this site, and would easily be able to follow similar instruction, if costly tools and materials are not needed for this task.

Thanks

you're looking at about 25-32PSI on the low side with the compressor turning and the AC running on MAX.

:thumbup: Thnx everyone for the input . I intend to do this the next couple of days (first chance I get work has been crazy ). I have residental hvac experience and when doing home hvac there is a table that list the other variables like ambient temp etc. That are useful.... I would love to have a copy of that table if it exist...... Are there are any techs out there that might share this with us . But with the info I have recieved this far I feel confident this will rectify my problem... If I am successful in recieving the table I spoke of I will consider doing a diy on this but I would like to insure I have all pertinant information before posting such ..... Thanks again to everyone on the forum you guys are the best :)

Yes, at minimum you will need a descent manifold pressure set. That being said. If you are in need of adding refrigerant. You will also need to seriously consider the real possibility that you have a leak in the system. Properely repairing a leak is much more involved, and requires many more specialized tools, and knowledge on how to do it. It took alot of reading and hands on for me to fully understand the process, so I urge you to do the same before attempting to service your AC system. Merely adding refrigerant without knowing how yours is opperating could lead to complete failure. Just price a new AC compressor. I almost fainted when I did. So, to answer one of your questions, yes it is DIY, but to do it properely is much more methodical than it looks.

Also If you look under your hood for the green tag, I believe the X5's only take 0.98 lbs to begin with, so adding a pound would essentially double the amount in your system... not good. Once you get the gauges hooked up, the low side should be somewhere between 25 - 35 psi, and the high side somewhere between 200 - 300 psi, varies with environmental conditions as you know. Also, for example, if your aux fan stops working, the high side pressure can shoot up to 450 psi with a quickness. Its amazing what effect it has on the head pressure....

If the pressures are off, like the low side is 45 psi or higher, etc. Then there is likely a problem with an ac component and would need repairs. If its low, even just a hair low, then it probably has a leak somewhere. I'd bring it somewhere with an "automatic" ac machine. It essentially is set to recover, vacuum (which removes any moisture from the system) and fill to the proper charge level. No over or under filling with this setup, which is highly recommended with a vehicle so temperamental to its charge level as one that takes just a smidge under a pound... even an experienced indy with his gauges and a can hanging off of them can't properly judge the correct amount on these

You bring up some very valid issues and I appreciate that. My first thoughts are (and tell me if I am flawed in my thinking) was to try to the best of my ability to self anaylisis my problem .
1. Put in dye and a small amount of freon
2. Check for leaks and see if cooling occurs
3. If leaks found go from there.... if no leaks are found read pressures and try to get a handle on the issue based on that.

Being as it is such a small quanity of freon needed in the system I too am afraid that I want be able to peg .98 with the equipment I have(Im good................ but I'll admit :wow: Im probally not that good)

4. Therfore after doing this intial troubleshooting I was planning on seeking a shop with hvac vacum recovery capabilities. and have them vacum and refill to .98

Sound like a workable plan? :dunno:

" I dont have a problem taking my x to a shop....... Im just one of those guys that wants to know why Im going before I get there..... I dont like surprises and I dont like paying someone to troubleshoot something if I can do it ."

Corima Thank you also for the warning ! If you have any of that left over reading material or links to it I would love to read it.

Now Im getting curious..........Has any one ever done this successfully themselves ?
Or has everyone who has done this just had a bad result ?
Or has everyone just bit the bullet and chosen to take em to the shop ?


Please Everyone dont take these questions above as a doubting of anyones advice .....I value each and everyones comments

I've done it successfully myself. the right hand side of the car was blowing warm and the left hand side of cool but not cold. check the pressure and it was low.

Recharged it and all is well. Doesn't seem to be leaking, however this was the first time it was checked/serviced in about 7 years, i wouldn't call that a leak...

Im glad to hear it went well for you........How did you go about assuring you only had .98 lbs of freon or did you just watch your high side low side pressures till they fell into range?

I just measured the low side pressure until i was in between 25-35. The only time that the 1 pound of charge would be any use is only once the AC system was evacuated and vacuumed , otherwise it would be next to impossible to use the 1 pound as a guideline with a system that has remaining charge.

Thanks alot ......Thats what weve always done on the ole homestead and it works fine I fell alot more comfortable now:thumbup:

I have been watching this post and successfully charged my A/C last night.

It took less than 15 minutes, once I figured out where everything is and triple checked the procedures before proceeding.

I picked up a Charging hose with pressure guage at AutoZone ($20) and a can of r134a ($8).
http://xoutpost.com/gallery/files/1/8...26-08_0744.jpg

After finding the Low Pressure valve (photo below shows its location on my '01 4.4i), I started the engine, AC to max, then attached the hose as outlined and pressure read about 20psi.
http://xoutpost.com/gallery/files/1/8...26-08_0745.jpg

I then turned the knob to begin the flow of r134a into the system and it immediately jumped to about 35-40psi (slightly greater than half of the good range on the dial, which is 25-45psi).

I let it sit for a few minutes, and the needle did not move. I check the AC inside the cabin and it was blowing cold. I removed the hose and replaced the valve cap and am happy to say I drove to work in comfort this morning.

My assumption is that, when connected properly, the hose and can of r134a become an extention of the closed AC system, and the system only takes what it needs to bring the psi up the the required level. From a product usage standpoint, it seems as if it barely took any r134a from the can, but the results were a 180 from what I was experiencing from my vents just minutes earlier. From reading other posts on this topic, it sounds as if the theories are correct that it does not take much of a loss of refrigerant to throw off the system.

I will let you know if my 95 degree+ drive home from work this evening is anything but "cool".

Thank you for the input.......and IM glad to hear of another successful job . However after all the input I've recieved on this forum and a few phone calls I've made I feel obligated to throw this out there for your consideration. I too have the typical handy dandy r134a kit and upon reading the generic instructions on the can I would say you hit your marks perfectly .....but being privy to some info shared with me from weasel56 & and a local bmw tech I must at least mention to you that our bmw's have a smaller threshold than some vechicle s described in the instructions on the can .Basiclly what Im saying is that I fear that the 45psi on the low side may exceed where you need to be. I have been told that it doesnt take but being low just a smidge to make your a/c hot. Therfore it stands to reason it wouldnt take much to put it into overcharged and possibly cause you compressor trouble down the road.
Im not making any allegations or accusations I just dont want you to be in a situation where you say "I wish someone would have told me" I fully intend to do the very same thing you just did the very same way. The only exception being Im gonna use my manifold gauges cause I trust my gauges more than the ones that come with the r134a and Im only going to charge till the low side reads between 25-35 (based on the best info I have recieved up to this point) It is my understanding that to go above 35 could put you in a state of overcharge. However I dont know the ambient temp and other varibles that existed when you did yours......... you could be spot on.
Im just throwing it out there for your consideration because I would feel terrible if a couple of weeks from now I read a post that you mysteriously lost your a/c compressor. Then again it could just be my paranoia creeping in again lol Best of luck

the compressor has a blow off valve if the pressures do get dangerously high, there have been people on this forum that have had this happen, and the valve has opened to vent the excess presure. Their systems were well over charged and all that was needed was to evacuate the system to bring it back into normal operating pressure again.

If you add 1 whole pound of r134a to a system that has not been evacuated and with an exisiting charge it will surely be over charged. Add enough for it to be within 25-35 psi on the low side with the compressor running on MAX, and you'll be fine, with no issue.

If you really are worried, pay for the piece of mind and take it to a professional.

Thank you Swiss.... Im not worried at all.... I feel like Ive gotten really good information and facts so I have no reservations about taking this on. I was just a little concerned (some call it a characther flaw) when unit107 said he had charged his to 45 and I had information in my possesion that told me that might not be advisable. I just wanted unit107 to be informed. Yourself and others all have said that 25-35 is a good working range so thats where I ll be..... and I do appreciate all the input

When I initially read the guage before introducing the r134a into the system, it was reading just shy of 20psi. The guage, unfortunately, is generic, with the "Safe" range indicated as 25-45psi, which I assume is somewhat of an industry standard when it comes to A/C systems.

After introducing the r134a into the system, it immediately jumped to barely over 35psi(the width of the guage dial over the halfway point of the 25-45psi range). With the setup I used to re-fill r134a, there was no way to "force" additional product into the system.

After reading some of your comments here and thinking about it for a while, it is quite possible that several factors came into play (air temp around 85 degrees, accuracy of the guage being slightly off, etc.). I feel fairly confident that the vehicle took what it needed, and that it is reading the appropriate level at this time.

I guess that only last few questions I would have to feel more confident about this adventure are: Are my assumptions correct about the system absorbing the necessary amount of r134a from the can, based on the system I used to refill? And also, if the range is 25-35psi, as perscribed by the manufacturer, what are the negatives of having the system pressurized to exactly 25psi or 35psi, versus being in the middle at 30psi on the nose? If it is that touchy, will I find the compressor sitting in my lap while crusing at 90mph with the A/C at MAX when the pressure is at 36psi(again, if the guage used was 100% accurate)?

I think this discussion has been very valuable(at least to me), as some posts seem to stop short in stating you can do something on the cheap, but don't go into the details on how it should be done properly and what pitfalls others might have encountered while making the fix. Hopefully this will be valuable to anyone looking to take this challenge on.

Im not really sure about the system taking what it needs part........ but I know I feel better now that I know there is a pressure relief or pop valve on the system. I also dont know what the exact results of overcharging the system is , and I hope we dont find out :) Im going to defer these questions to weasel and swiss frank they are far more knowledgeable on this subject than I .
I do agree on the part about some post not being talked through at length and covering all the bases ,but I think we have about covered all the bases on this one if not .......anyone please feel free to comment

o.k heres wheres we are at in the saga . I put the gauges on the x today I pulled the x in the garage last night just started it up. It will blow cold cold air on start up gauges show 36 low side and 250 high side ..welll im thinking thats bout right so I drive it down the road bout 2 miles about a mile into the trip passenger side is hot, middle is hot and drivers side is cool , rear is cold so we pull into the gas station aux fan is running fine . Now the only confusing thing is the control in between the air vents (red dots and blue dots) It does not feel like the wheel goes into position when I try to put it at 3 blue dots but if I hold I can feel the temp get cooler . How is this control operated is it cable, relay or air Im thinking this is my problem but not sure anyone got some info along these lines ? i hate to assume its fsr I have nothing to make me believe it is unless Im missing the symptoms , but Im really not exactly sure what the fsr does , if anyone would like to take a stab at explaining that , it would be appreciated.

Surely this is not a first .....somebodys bound to have seen this before...One additional note there seems to be extremly more condensate draining from the bottom of the x

That adds some more vital info to the equation... Lets get this straight. When you first start it, it blows cold... the longer you drive it, the warmer it blows. Yet it drops ALOT more water condensed out of the air... That all leads to just one situation! Your AC is working FINE, just the air is being re-heated by the heater core before it makes it to you!

I believe the wheel on the vents operates a cable as well as a microswitch when it gets to the full cold position, likely just a microswitch thinking about it...(differrent on different cars) The heater is controlled through electronically operated valves. If the wheel is not fully going to the end position, it may be hanging up on the switch lever... Whatever the cause is, the problem is that the heater is reheating the air after the ac cools it. For a temporary solution just to get cold air until the cause is found/fixed, simply unplugging the heater valves might leave them closed. (unless they default to open, but I doubt it) If you look near the drivers side inner fender, kinda at the inside of the strut you should see the heater hoses... the valve body in them with metal solenoid valves on it, unplug it and try again. If I'm right, you will retain cold air... if not, try gently crimping one of the hoses from it to the firewall closed with pliers to see if they're mechanically stuck open. Which would mean heater valve replacement.

Sounds like great advice, but I think i confused myself, lol.

Just the fact of the extra amount of condensation water dropped by the ac proves that the evaporator is getting as cold as ever... Now it's just a matter of figuring out if the heater problem is a control problem or a mechanical fault. Yet again, I love the BMW diagnostic equipment at the dealer... "status requests" accessed through "control module functions" will tell you the status of all switches and signals in the system, and "component activation" will let you play with the system telling it what to do.

Without that, it just takes knowledge of the system to be able to diagnose it yourself... much of which can be obtained through the WDS link on this site. That is the same wiring schematics system we have at the dealer. You can look up all the switches and controls in the system if you know how to use it.;)

:cool:

Weasel
I have autoengunity would it show that faulty switch.
HEY THANKS
Thats very handy Gridlock Im gonna print that and keep it :) :thumbup:

:welcome:

the switch is just one of the possible problems, it is more likely that the valves are sticking. But it is worth checking to make sure it is not still being told to stay open... which just means checking it with a voltmeter. But from the sound of it, I'm pretty sure thats your problem.

Ok heres the update on my situation I come home thur and as I pull in my driveway the check coolant light comes on ...ok no biggie so I check the coolant resivoir and its needs coolant so I add it problem solved I thought. The next morning I get ready to leave I look under the x and I have a puddle about the size of a baseball I examine it and its antifreeze I need to make a short trip into town 7 miles round trip so I take the x and a gallon of h20 with me. I get to the store come out and I see more antifreeze under the x so I let it cool..... check the coolant level and its low again I add more water and drive home. Im successful in making the short trip with out elevating the temp and getting a coolant alarm. After getting home I call a friend and he brings over a pump we put it on the radiator resevoir and pressurize the system I discover a leak on one of the small hoses on the back of the motor coming from the heater core ....damn near impossible to get to. So the x is now at the shop to get that fixed and they will take a look at the a/c also while there. More news to come as I get it. I passed on all the info to the s/a hopefully that will save some time troubleshooting.

Well hopefully you will get it all fixed in one shot. Maybe it's just coincidence, but the heater hose's life was probably cut short by having constant pressure in it... I still seem to think it's a heater valve problem with the ac, judging it was ac condensation seen previously and not coolant.

And now ......the rest of the story I hate when a thread has no ending being good or bad ..so here is the conclusion to mine. Took the X to the shop and after pressurizing the coolant system the furtherest back hose comin from the heater core back to the engine had a crack in it ,(and let me tell you it was hard to find it envolved two extendable mirrors and a flashlight) that being replaced resolved the coolant leak while he was repairing the hose he found that a plug had come unplugged at the rear of the climate control computer plugging it back in resolved my a/c issue. Thanks Again to Weasel and all the other fine folks at x5world for their help in this matter

Good to see it is all over and done with, and was simple problems at that!