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E34 (1989 - 1995)

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  #1  
Old 11-29-2014, 04:34 PM
tristero tristero is offline
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basic AC troubleshooting?

I haven't invested in any specialty tools for AC yet. I'm wondering if I could just invest in one of those $30 recharge cans and get that to work.

What I'm seeing is that the pully turns fine, so the compressor is not seized. When I turn the pully by the shaft-nut, I heard kind of a faint sloshing. I couldn't tell if that sound was coming from the compressor, or from the condenser. Is this coolant or AC lubricant?

However, when I turn on the A/C inside the cabin, the compressor does not seem to run at all.

I have no idea how long the system has been non functional. At least since I bought the car back in February.

Is it likely that my compressor is FUBAR, or does the system just need a recharge?
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  #2  
Old 11-29-2014, 04:43 PM
Alpina535I Alpina535I is online now
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Just get a recharge kit and plug into low side with car on and a/c on full blast. Gauge will tell you when your in the green to stop filling. The m50 is like 3.47 pounds of freon I filled mine with 3.17 for my m30. Also add a can of oil before filling with freon since its been a while since the system has been charged most likely.

Alpina
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  #3  
Old 11-29-2014, 05:23 PM
paul1733 paul1733 is offline
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We don't have any DIY recharge kits here nor do we use freon gas because of CFC's we use R134A gas. Just some info from the other side of the world.

if you have to recharge your system you have a leak, get it pressure tested because the gas should last a hell of a long time, a fridge is a good example.
When I got mine regased 4 years ago they added a dye to detect leaks still cold today.
Also you should run your a/c at least once a month to keep the seals lubricated.
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  #4  
Old 11-29-2014, 06:02 PM
MeNoo MeNoo is online now
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Quote:
Originally Posted by paul1733 View Post
We don't have any DIY recharge kits here nor do we use freon gas because of CFC's we use R134A gas. Just some info from the other side of the world.

if you have to recharge your system you have a leak, get it pressure tested because the gas should last a hell of a long time, a fridge is a good example.
When I got mine regased 4 years ago they added a dye to detect leaks still cold today.
Also you should run your a/c at least once a month to keep the seals lubricated.
I beleive that R134 is a type of freon... Also, after x amount of years it is common to get a minor drop in pressure, a major drop would signify a leak.
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  #5  
Old 11-29-2014, 06:22 PM
tristero tristero is offline
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Quote:
Originally Posted by Alpina535I View Post
Just get a recharge kit and plug into low side with car on and a/c on full blast. Gauge will tell you when your in the green to stop filling. The m50 is like 3.47 pounds of freon I filled mine with 3.17 for my m30. Also add a can of oil before filling with freon since its been a while since the system has been charged most likely.

Alpina

Alpina535i; thank you - - how do I add oil? (I assume you mean the special oil for air conditioners - I see a howto video online, that adds the oil, but the compressor is out of the car in the video. Is it possible to add oil to the compressor while it's still in the car?
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  #6  
Old 11-29-2014, 06:29 PM
Alpina535I Alpina535I is online now
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Yes they come in 4 ounce cans inject same way you would freon. I would get the system vacuumed first if you don't know how long it's been since last full. Also Paul is half correct just because there is no freon in the car does not mean a leak. My car had no freon in the system and I filled and has not lost any for over 9 months. Not saying he is fully wrong but it's not for all cases.

Alpina
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  #7  
Old 11-29-2014, 06:31 PM
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Those DIY recharge cans contain PAG oil, just use them.
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  #8  
Old 11-30-2014, 02:44 AM
paul1733 paul1733 is offline
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Quote:
Originally Posted by MeNoo View Post
I beleive that R134 is a type of freon... Also, after x amount of years it is common to get a minor drop in pressure, a major drop would signify a leak.
Freon is a brand name of Dupont that contains CFC's which our country phased out years ago also known as R12. R134A does not have CFC's. There both refrigerants just one is better for the environment. If the air isn't coming out cold there's no refrigerant so you have a leak in the system.

I'll just add to that so everyone is happy, thanks Alpina not sarcastically thats for sure. If there is gas the problem could also be electronic, whether compressor connection/malfunction, a/c button connection/malfunction or climate control switch connection/malfunction. Apologies, there BMW's alot of things are complex but a/c is a very simple system.

Last edited by paul1733; 11-30-2014 at 06:10 AM.
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  #9  
Old 11-30-2014, 09:13 AM
Mr._Graybeard Mr._Graybeard is offline
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A compressor with a low charge of refrigerant will cycle on and off. It will run for about one second before the pressure sensor shuts it down. After about five seconds, the compressor will spin again for a second, then shut down. Over and over. Are you sure it's not spinning at all, Tristero?
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  #10  
Old 11-30-2014, 03:50 PM
MeNoo MeNoo is online now
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Quote:
Originally Posted by paul1733 View Post
Freon is a brand name of Dupont that contains CFC's which our country phased out years ago also known as R12. R134A does not have CFC's. There both refrigerants just one is better for the environment. If the air isn't coming out cold there's no refrigerant so you have a leak in the system.
My bad about the freon. I always manage to make myself look like an idiot on BF. Adding to culprits for the OP, I have seen the compressor clutch not engage properly (Both on a Toyota and a Subaru) . The fix was to get it off the car and hit it against a table. It worked both times and the owners of the cars were happy to have cold AC in 100+ degree weather.
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  #11  
Old 11-30-2014, 04:32 PM
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Quote:
Originally Posted by Mr._Graybeard View Post
A compressor with a low charge of refrigerant will cycle on and off. It will run for about one second before the pressure sensor shuts it down. After about five seconds, the compressor will spin again for a second, then shut down. Over and over. Are you sure it's not spinning at all, Tristero?
That does not always indicate a low charge, but a good hint.
To test the compressor jump the low pressure switch, located behind the passenger headlight(us version) just below the hood shock mount, hard to find sometimes so i can get an image if you need it. Just turn the ac on a nd lump the tow pins for a second and see if the compressor comes ones on, if so then it is low/has no 134 in the system. So go to a hop if there are not DIY kits available and get it tested from there on.
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  #12  
Old 11-30-2014, 11:36 PM
tristero tristero is offline
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I don't think the compressor was starting and stopping - I don't think it came on at all. When I get the motor back together after my oil pan gasket refresh, I will try jumping the low pressure switch, and I'll try a recharge can.
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  #13  
Old 12-01-2014, 03:22 AM
paul1733 paul1733 is offline
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Quote:
Originally Posted by MeNoo View Post
My bad about the freon. I always manage to make myself look like an idiot on BF. .
I'm not phased pal, your trying to become blue collar scum like myself.
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  #14  
Old 12-01-2014, 08:31 AM
Mr._Graybeard Mr._Graybeard is offline
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It's possible to overfill AC systems with refrigerant, although I doubt you'll have that problem. But I'd try to diagnose the problem further before I just started pumping gas into it.

You may want to look for refrigerant with ultraviolet tracer dye so you can detect any leakage with a black light. Then, if the gas leaks out you can find the source.

One thing you didn't mention -- does the AC button light up when you press it? I suspect you've checked to ensure that it does, but it doesn't hurt to ask.

If you want to do some useful research on AC, check out aircondition.com. It's got a great FAQ section and a forum where some automotive AC pros hang out.

Last edited by Mr._Graybeard; 12-01-2014 at 08:48 AM. Reason: Fact check
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  #15  
Old 12-01-2014, 09:30 AM
tristero tristero is offline
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Yeah the button lights up.

There are three temperature control knobs on this car. The two blue-to-red dials on either side of the fan control (and the one on the left "clicks" at full high and low temps; the one on the right has no "clicks" - wondering if that's normal or if the knob is broken). The third control is a roller wheel in between the two vents in the middle of the dash, (above the radio) -- if I spin it all the way up, the markings are red, and hot air blows, if I spin it all the way down, the markings are blue and cool (not AC) air blows. This third control seems to be independent of the other two knobs. Pretty weird.
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  #16  
Old 12-01-2014, 11:07 AM
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Use something with a soft blunt tip, like retracted pen (non-metal) tip. Just quick press the low-side A/C valve (Hint: bigger line). If it vents pressure, you will want to begin electrical testing, as was suggested to jumper the pressure switch to attempt compressor cycling. If it vents pressure and compressor will not come on at all, you most likely have a bad compressor and/or compressor clutch. If vents, and compressor cycles, get DIY "Refrigerant."
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Last edited by TheEinstein; 12-01-2014 at 11:08 AM. Reason: Rewording..
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  #17  
Old 12-01-2014, 11:11 AM
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That is normal operation for the climate control knobs. My understanding of the clicks for drivers side, is that you are basically selecting constant open or close for the heater valves depending on climate cooling or heating.
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1995 E34 540ia
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VIN# ...GF32404
Hellrot Red

Fuelly

My Basic Repair History (Edited 4/7/2014)

Ongoing comparison between two E34 540ia's

OBC4 Hidden Functions : Link 1, Link 2
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  #18  
Old 12-01-2014, 03:12 PM
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E34ZombieHunter E34ZombieHunter is offline
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Quote:
Originally Posted by TheEinstein View Post
That is normal operation for the climate control knobs. My understanding of the clicks for drivers side, is that you are basically selecting constant open or close for the heater valves depending on climate cooling or heating.
The clicks are "over-ride", they do what you said, but do not allow the passenger to select a temperature when in the click.
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Gotta love an E34!!
If you want to get junkyard parts remember one thing, if it was wrecked you know it was running/driving. You may not know how well, but it was.

READ THE STICKIES AT THE TOP OF THE PAGE!!

STOMP TEST

READ ME IM THE BIBLE

FAN CLUTCH

LOCKS

ANGEL EYES

Audio

E28 v. E30 v. E34
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  #19  
Old 12-01-2014, 03:27 PM
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Originally Posted by E34ZombieHunter View Post
The clicks are "over-ride", they do what you said, but do not allow the passenger to select a temperature when in the click.
Thank-you for the clarification.
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1995 E34 540ia
155,000 Miles
VIN# ...GF32404
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My Basic Repair History (Edited 4/7/2014)

Ongoing comparison between two E34 540ia's

OBC4 Hidden Functions : Link 1, Link 2
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  #20  
Old 12-03-2014, 09:34 AM
tristero tristero is offline
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Still working on re-assembly. The oil pan removal was kind of a stretch-job for my skill level. I feel like I just went from "tristero the grey" to "tristero the white". Anyway; neither of the AC line valves has any pressure. System is empty. I'm going to assume on a system this old, there's a leak. Compressor turns and "sloshes", so there's oil in there somewhere. I will probably be able to get the engine back together by Friday, and I'll dump a can of r134+tracer+oil+stop-leak in there, and see what happens. It may be that the PO just let it all leak out and got sick of re-filling it because it's a bad leak. He was very meticulous in keeping this car in good repair, but I don't think he was a DIY-er. He wasn't shy about paying a lot to maintain it, because he had re-done all the suspension bushings and replaced the radiator several times over the years. The only things he left me with were the bad AC, oil leak(s), and a busted fog light.

Again, thanks for the help everyone.
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Old 12-03-2014, 09:37 AM
MeNoo MeNoo is online now
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Quote:
Originally Posted by tristero View Post
It may be that the PO just let it all leak out and got sick of re-filling it because it's a bad leak. He was very meticulous in keeping this car in good repair, but I don't think he was a DIY-er. He wasn't shy about paying a lot to maintain it, because he had re-done all the suspension bushings and replaced the radiator several times over the years. The only things he left me with were the bad AC, oil leak(s), and a busted fog light.

Again, thanks for the help everyone.
PO was first owner?
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  #22  
Old 12-03-2014, 01:00 PM
tristero tristero is offline
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PO was the second owner, I think. He kept records, from 2001 to present. Previous owner did not. A check of his records didn't show any AC work.
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  #23  
Old 12-03-2014, 04:24 PM
MeNoo MeNoo is online now
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Quote:
Originally Posted by tristero View Post
PO was the second owner, I think. He kept records, from 2001 to present. Previous owner did not. A check of his records didn't show any AC work.
Still, he sounds like a half decent PO. It almost seems like we're adopting children, and have to know what their birth parents treated them like.
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