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Compressor Engages and then turns off


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Beamer.619
Novice

Dec 29, 2020, 11:37 PM

Post #1 of 21 (1253 views)
  post locked   Compressor Engages and then turns off  

I've been trying to get the AC working properly on my BMW 750iL 1992 for a while now the first time I tried to getting it running a few months ago when I filled the car with refrigerant I noticed it had a leak so I found the leak which was because of a ac line So I installed the replacement ac line and a new drier then pulled a vacuum for 2 hours then started to fill the system with refrigerant and I saw the compressor engage for about 5 seconds then turned off so I took the relay out and bypassed it with a wire so the compressor was running right when I started the car so I started filling the system with the rest of the bottle of refrigerant and took most the bottle then the belt started slipping on the compressor and made a loud screeching noise and then the compressor clutch shut off so I turned off the car. I then pulled the wire out and put the relay back in the car and tried the running the compressor it tried turning on but the belt kept slipping for about 3 seconds and then it gave up and just wouldn't engage. What could my issue be so far I haven't see anymore leaks from where it was leaking from.

Here's a video of the clutch trying to engage when i turn on the ac.
https://youtu.be/WIgMsGF1fQo


(This post was edited by Beamer.619 on Dec 30, 2020, 12:17 AM)


Tom Greenleaf
Ultimate Carjunky / Moderator
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Dec 30, 2020, 12:29 AM

Post #2 of 21 (1228 views)
  post locked   Re: Compressor Engages and then turns off  

I didn't find this exact model listed in some OLD paper charts for it. 1st question is for 1992 see BMW was using mostly 134a is rare as most were R-12 so need to know if it was OE for which and what you are using now would help.


Screeching when compressor forced? #1 it has way too much refrigerant is choking on it as a liquid not returning a gas in seconds may have destroyed it or not can't tell this video you posted here as a link > https://vimeo.com/...495685483/58fc4a7b1d < didn't show not sure I need it.
Steps when you find a leak is now guess how much oil you lost AND how long it was low if you can tell. Lube of either refrigerant is carried by a proper charge or real close in this a high capacity system oil doesn't move well or at all if charge is low should have defaulted to not engaging ever BTW all are too late that I know of cause damage trying to run while low if not sudden loss leaking out in no time.
How much oil came out of parts you replaced also? Cut parts open if not easy to know measure it. Driers drill a hole in those to measure oil that was there.
Put that much back then add the guess of 2 OZ of oil suggested 1/2 upstream, 1/2 downstream so you don't just choke on oil either.
I'm going to be at a loss this year of any BMW is missing info on what refrigerant even never mind how much.
That will be key and if converted/retrofitted need to know how done could have been YEARS ago now if new OE was R-12 the system capacity has to be ascertained hope if that was done it was clearly marked.
For now it's choking on some liquid most likely way too much of either refrigerant or compressor seized up and you didn't know it or see it turn from hub of compressor should spin new oil in first I think this was low way too long and is demonstrating "Catastrophic Compressor failure" so isn't going to be near cheap or easy now so common in anything and OMG in a BMW.
Other: Not my cars if sold here and can't find it or info is now up to you to find what it was or happened since model year 1992 all fine just need a good history or this will be all hell to get going.
Other 2: Go real easy on jumping things in all but some well known very plain CCOT systems by all odds this is an TXV set up and or also has a sight glass - tough info on this exact model year for me - sorry,


Tom



Beamer.619
Novice

Dec 30, 2020, 1:12 AM

Post #3 of 21 (1219 views)
  post locked   Re: Compressor Engages and then turns off  

My bad I left out alot of info the car was retrofitted from r-12 to R134-a in 2000 and the car had been sitting for about 15 years until within the last year I got it running again. When I took the system apart I drained the compressor and barely any oil came out I don't even think there was a oz of oil. After it was drained I filled the compressor with 5.7 oz of ester oil since the retrofit tag says that's what they used. The tag says they used 4 oz of ester oil I put in a extra 1.7 oz for the condenser since I flushed it out and for the new drier hoping when the compressor ran the oil would circulate through the system. I also replaced all the orings I had access to. And I updated the link now you should be able to watch the video now on youtube. Also here's a picture of the retrofit tag https://imgur.com/e5BGFDS I think they meant to write 4.24 under oz for the amount of refrigerant they used correct me if im wrong. If they meant 4.24 oz I definitely did overfill the system because I put in almost the whole bottle and the bottle holds 12oz so there's probably around 10 oz in the system. What should I do next?


(This post was edited by Beamer.619 on Dec 30, 2020, 1:22 AM)


Tom Greenleaf
Ultimate Carjunky / Moderator
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Dec 30, 2020, 2:04 AM

Post #4 of 21 (1210 views)
  post locked   Re: Compressor Engages and then turns off  

OK, Please bear with me web is cutting out where I am doesn't help of course. It's 3:30AM Boston time even?? The "retrofit" tag is what to go by for amounts, if not clear need to know OE amounts to find the right charge new. 134a would be or I would start at ~65% of OE charge for R-12, spend over an hour finding the % and know how much it took. Archive that info.
Problem with sitting so dang long is compressor couldn't take that!
What do you wish to do because your ounces don't add up I think this hold pounds certainly not 4-5 ounces. It may not list in ounces might be another measure USA is metric partial - can't help it A/C doesn't work well if not using ounces and Fahrenheit to know how to deal with converted vehicle IMO and did countless and like Ester oil also.
Time sitting oil drains to bottom of everything so initial start up if you can't spin one must know you are doing so by hand, belt off or on if you can reach center of compressor as if engaged NOT just the pulley/clutch you forced on a frozen compressor - my guess with no oil in there for so long it froze up - it's ruined never mind the leak you found and can on a dead vehicle that doesn't run!
How much do you want to invest this is both old and BMW - cool if you love it not if you like cheap repairs.
If the retro included a new condenser need to know that now if so it also is wrecked. One wrong thing takes out parts downstream with debris after 15 years would probably take it apart before trying to make it work or kill it for good.
Hoses for 134a really have to be "barrier" hose not NOS stock for R-12 would work just seep thru like a party balloon doesn't hold air very long if you follow me?
It's hard in the best of situations this just harder for access to get at things than some others.
Refresh this: I think you should start over where I am 134a is dirt cheap IDK if you can recover it or if anyone would knowing this much about it??
I would have taken compressor off and spun oil thru it on workbench as if it was new till Ester oil cam out exit port. It was dry by 15 years actually a year is a lot.
Other: It's off season where I am (metro Boston inland a bit) is 21F right now my shop (remote check) is 44F I couldn't get products to work at those temps few can by chance around me that I know of.
Question: Do you know how to spin compressor knowing you are spinning the shaft inside by hand not where the belt goes? You need to do that also suggest belt off you said clutch is probably crusty would burn off if not excessive is really separate to it being a compressor.
If it can't spin smoothly by hand that's already taken out downstream parts with debris! New in 1 minute are no good now.
Condenser? What type was retrofitted in? OE would be flushable the proper one for post model year 1993s are not.
My area for retrofits asked customers how badly they wanted BTUs at 80% of what it was new! It's hot for a month most thrilled to just get humidity down inside cabin and less volumes of cool air vs OE designs. We were caught in a jam, costs insane vs how long you wanted it to work as best it could. Informed customer decides that always stressing "informed" this is costly stuff and any mistake can set you back worse off than when you started in no time hope it didn't but real worried.
I'll be off-line now but want to know how far you wish to go with this yourself or send it out and shocked at what this could cost!
That's the question for now is are you determined to make this work as best as possible I now see why it's failing simply 15 years is way too long the approach was wishful didn't work at all still unsure of what it will take is tough to know this needs some serious time to know what it will probably not for the web but a pro in person to even make the call for you as to what it needs. You then decide if you want to try or pay these are costly cars either go for it at any cost or do without A/C is the choice of many for where I am not the whole world,
Tom



Beamer.619
Novice

Dec 30, 2020, 3:36 AM

Post #5 of 21 (1208 views)
  post locked   Re: Compressor Engages and then turns off  

The condenser I'm assuming is the OE because its the older style condenser with the thick lines going through the fins. And yes I can spin the center of the compressor with my hand its not stuck I did this after I put the new oil in and I watched the shaft rotate with the manifold off of the compressor should there be a slight drag when rotating the part or should it freely spin with no resistance? And I don't plan on spending hundreds on a new compressor on this car its very old itself I was just trying to see if I could get it running with what it already had and a new drier. There's a tag on the compressor with specs on the back of it I see it says 200cc of oil which converts to 6.7 oz is this max amount of oil the compressor can hold? Here's a photo of the tag https://imgur.com/mbGE1Ft


(This post was edited by Beamer.619 on Dec 30, 2020, 3:40 AM)


Tom Greenleaf
Ultimate Carjunky / Moderator
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Dec 30, 2020, 4:59 AM

Post #6 of 21 (1194 views)
  post locked   Re: Compressor Engages and then turns off  

OK: Struggling dammit my chart avoided model year '92 so '91 shows "total system oil charge" for "front only" A/C set up was 6.75 ounces. Then a charge of 68 ounces of R-12 is 4.25 pounds. You said using 12ounce cans your guess is only 10 got into a vacuum which squealed the belt.
Quote you here ">I think they meant to write 4.24 under oz for the amount of refrigerant they used correct me if im wrong. If they meant 4.24 oz I definitely did overfill the system because I put in almost the whole bottle and the bottle holds 12oz so there's probably around 10 oz in the system. <"
That's enough to have "static pressure" if ambient air is about 80F (perfect for A/C work) with charts and pressures would kick on a compressor but no load on it while running yet but it choked?
I can't read its mind so compressor spins (great) with that in hand feel some compression is what you said still great. It's going wrong squealing the belt though so where's the problem? IDK but default is compressor itself under speed of engine has either choked on oil(?) or just wrecked inside(?) back both from being low and sitting 15 years.
The guess for oil is what's still in it NOT just the compressor. That's what it can hold for a system if it ended up there.
The history of leak I think will remain lost to both you and me.
Other things flushed or air blown thru parts is where old oil still may be many none in compressor I think you said that. Fine then it last quit with is either hiding in (now known) tube and fin condenser, or in evaporator in dashboard?
This and some other cars will convert pressures to temps to switches and shut them down. Since it's NOT too much refrigerant it's too much oil usually lots more than you added or compressor is just messed up under engine speed.


That last comment by me is what I think the problem is and you don't wish to spend a fortune I wasn't talking USD $100s was going so say USD $1,000s! That most people wouldn't spend without a love affair for this exact car that sat for 15 years is the game.
Are you able to forget A/C or mandatory for you?
Sorry for such long reads here - both of us, there's so much to know about A/C in vehicles it takes years to get it and still can't know everything that can go wrong.
YouTube type things are great if and when you already know totally what a problem is 100% and hope what you find isn't crap info.
I'll quit and let another here read some of this - OMG there's tons already but with what I see this compressor and drier if with desiccant has to go again by the book or the risks are doing every last thing over again is why A/C as a trade is so costly - not 100s - 1,000s as said and BMW doesn't care about YOUR money as cars go it's one of many that don't,


Good luck and I'll hope but this needs some in person diagnostics if you wish to do more already said that BTW you've done real well so far this stuff isn't easy like things make it look,


Tom



Hammer Time
Ultimate Carjunky / Moderator
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Dec 30, 2020, 5:00 AM

Post #7 of 21 (1192 views)
  post locked   Re: Compressor Engages and then turns off  

It sounds like you are charging this with way too much refrigerant and oil.

Depending on the production date of the car original R12 charge was 4.24 lb up to 11/92 which means a retrofit of R134A would only be 3.3 lb.

If it was built after 11/92 the R12 charge drops to 3.4 lbs which would be 2.7 of R134A

It sounds like you also put way too my oil in the system as there was residual oil left throughout the system left behind. I would have added no more than 4 ounces total.

There was also no need to jump out any relays. It is normal for the compressor to cycle until it takes in enough refrigerant to stay running.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Beamer.619
Novice

Jan 1, 2021, 4:48 PM

Post #8 of 21 (1151 views)
  post locked   Re: Compressor Engages and then turns off  

Could this issue be because of my expansion valve I'm starting to think it is because even when I forced the compressor while there was refrigerant on no cool was coming out of the vents I think the expansion valve is maybe stuck closed not letting the compressor generator the draw of refrigerant from the lowside that would also make sense that the compressor will turn on for a few seconds and then turn back off. What do you guys think of this theory.


Tom Greenleaf
Ultimate Carjunky / Moderator
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Jan 2, 2021, 1:44 AM

Post #9 of 21 (1146 views)
  post locked   Re: Compressor Engages and then turns off  

Back to post #3 Quote ">I put in almost the whole bottle and the bottle holds 12oz<" ???????????
What are you doing messing with those vs other and better for BMW insane repair costs is part of "Exotic Euro" cars like it?
You can't be over charged with only that can. Yet it's choking or screwed up another way I/we can't see, hear or observe just what are lost sometime (go ahead and blame me) can't fix everything over web info.
You've forced it to engage compressor by jumping electrical things. That alone in a Euro car of this caliber could break you and would me.
You are apparently and well understood trying to save a buck and costing yourself a fortune. Not much A/C is just hit and run fix and most any failure is backwards meaning wrecks more than you thought.


Said I'm sure and the sing-off oh Hammer Time some things need in person, professional inspection a BMW of age now best bet IMO is a dealer and you won't like the cost is why used they are so hard,


Tom



Hammer Time
Ultimate Carjunky / Moderator
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Jan 2, 2021, 5:46 AM

Post #10 of 21 (1140 views)
  post locked   Re: Compressor Engages and then turns off  

Refrigeration diagnosis is not a DIY task. It requires a great deal of observation and knowledge to determine exactly what is happening in the system.

I assure you. The expansion valve IS NOT your problem. Get it to a competent shop that specializes in AC repairs.

As Tom pointed out, all you are going to accomplish here is possible severe damage.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



(This post was edited by Hammer Time on Jan 2, 2021, 5:47 AM)


Beamer.619
Novice

Jan 5, 2021, 3:18 PM

Post #11 of 21 (1103 views)
  post locked   Re: Compressor Engages and then turns off  

I got a new compressor, expansion valve, and drier the car was retrofitted in 2000 from r-12 with mineral oil to r-134a with ester oil. I'm doing a full system flush and replacing everything except for the condenser and evaporator my question is should I use ester oil since that's what they used when they retrofitted it or should I use pag oil.


Tom Greenleaf
Ultimate Carjunky / Moderator
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Jan 5, 2021, 3:56 PM

Post #12 of 21 (1098 views)
  post locked   Re: Compressor Engages and then turns off  

Just that question on Ester oil? I say yes. Why is it's supposed to agree with any (if any) remaining mineral oil NOT tested by me PAG oils and mineral oils don't mix together,


T



(This post was edited by Tom Greenleaf on Jan 5, 2021, 3:57 PM)


Hammer Time
Ultimate Carjunky / Moderator
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Jan 5, 2021, 4:55 PM

Post #13 of 21 (1089 views)
  post locked   Re: Compressor Engages and then turns off  

I've seen a number of shops use PAG oil with good results. I would get as much of the mineral oil out as possible first.

Ester oil has a lot of down sides.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
Ultimate Carjunky / Moderator
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Jan 5, 2021, 5:17 PM

Post #14 of 21 (1083 views)
  post locked   Re: Compressor Engages and then turns off  

All others new with 134a use PAG 100 upon look up. There's a reason they choose that so if you get the mineral out well use that. I've also heard of "downsides" to Ester but know A/C isn't worked nasty hard where I am. That info then came from Phoenix, AZ is as populated for super hot city as it gets that I know of? Also dry PAG is said to go acidic with an open system happens around me lots from plain damage thru a long off season so I just worry but can't prove that either in person,
T


Beamer.619
Novice

Jan 5, 2021, 5:57 PM

Post #15 of 21 (1079 views)
  post locked   Re: Compressor Engages and then turns off  

Thanks for the much needed information guys since I'm doing a complete system flush it looks like pag oil 46 is my best option ill report back after the system is back together and recharged still waiting on the parts.


Hammer Time
Ultimate Carjunky / Moderator
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Jan 5, 2021, 6:30 PM

Post #16 of 21 (1072 views)
  post locked   Re: Compressor Engages and then turns off  

Given the symptoms you started with, I would give a lot of consideration to the condenser and discharge hose. The other parts are going to do nothing for the original symptoms of the compressor locking up.

If you don't find the original problem you will likely take out the new compressor.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



(This post was edited by Hammer Time on Jan 5, 2021, 6:32 PM)


Beamer.619
Novice

Jan 11, 2021, 2:10 AM

Post #17 of 21 (926 views)
  post locked   Re: Compressor Engages and then turns off  

Just got the refurbished ac compressor in today and the clutch shaft is very hard to spin is this normally or is that bad signs for the compressor?


Hammer Time
Ultimate Carjunky / Moderator
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Jan 11, 2021, 3:07 AM

Post #18 of 21 (924 views)
  post locked   Re: Compressor Engages and then turns off  

If you are using a refurbished compressor you are better off with no compressor at all. You are already replacing a compressor which according to your description, has not failed yet. Using a reman compressor is a step backwards. They don't hold up very well at all and I would never use one.

As for your question, that would be normal if you haven't removed the caps yet and would still be very tight even if you have.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
Ultimate Carjunky / Moderator
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Jan 11, 2021, 9:52 AM

Post #19 of 21 (916 views)
  post locked   Re: Compressor Engages and then turns off  

Refurbished is a no go IMO also. You can't spin it now or didn't follow instructions with just repainted junk so lost. New friend, there's enough that goes wrong to set you back worse off then before you started,


T


Beamer.619
Novice

Jan 17, 2021, 12:15 AM

Post #20 of 21 (882 views)
  post locked   Re: Compressor Engages and then turns off  

Got the compressor running with cold air everything seems fine.


Tom Greenleaf
Ultimate Carjunky / Moderator
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Jan 17, 2021, 1:38 AM

Post #21 of 21 (876 views)
  post locked   Re: Compressor Engages and then turns off  

Good for you. This is + was a tough bird of a vehicle, the model year(s) and more so be happy and I hope it last for you.
Closed as done/solved just ask any moderator to reopen this if you wish,


Tom







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