opinions sought on AC leak repair

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  #1  
Old 06-02-03, 04:21 PM
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opinions sought on AC leak repair

Just wondering if any of you folks have any opinions regarding
fixing AC leaks.

I have an 88 528e with 88K miles with an R12-based system.
Unfortunately since it's a "low-mileage" car, I'm sure the
seals have probably dried out prematurely compared to
my older "high-mileage" 84 Toyota which is still pumping out
ice cold air.

The AC was fine until about 3 yrs ago when I had to
recharge it with just less than 1 pound of freon
to get it cold again. Now, it looks like I have to put in
another can of stuff.

It's obvious I have a very, very slow leak somewhere,
and obviously nobody legally sells anything R12-based
over-the-counter. :-(

Unfortunately, AC repair isn't something I can do on my
own, so to avoid being taken for a ride , I'm wondering
what's the first thing a shop will want to do whether I
need it or not. Repair/replace gaskets/o-rings? I assume
that won't be cheap.

Some dumb questions:
- I assume I'll have to evacuate and recharge the system
since it'll be full of air sooner or later. If I take the car into
a shop, is asking for them to use leak sealant and simply
evacuate/recharge a valid request?
- since I seem to lose about 1 lb of freon every 3yrs, what's the
easiest way to locate and detect the leak? I seem to remember
hearing something about using a propane torch, but I'm not sure
I want to holding a torch inside the engine block while the
engine's running. If I can identify what/where the problem is, I
can a least refute anything from the shop that I don't believe.
- I don't plan on replacing the system with an R34-equivalent.
I think I'd rather drive with the windows open or get a
new car :-(

any insight or opinions would be great

thanks
aaron
 
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  #2  
Old 06-02-03, 06:27 PM
darrell McCoy
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A reputable dealer will use an electronic sniffer/beeper. Seen them work and do a good job. Leak is more than likely a compressor seal from what you describe. This is the expensive part. But then it could be a hose connection. Pinhole in evap or cond. I would take it in, let them find the leak and then get an estimate on the repairs. R-12 has become quite expensive. However, without proper guages it is not wise to attempt to fill the system yourself. I have never seen a "stop leak" that works on an A/C system. As you know A/C systems are not for a do it yourselfer. No doubt the leak will get worse as time goes by.
Basically a matter of your own choice as to whether repair it or nurse it along until it finally quits completely.
 
  #3  
Old 06-02-03, 06:41 PM
Jayhawk
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I agree. A/C leaks are sometimetimes so miniscule that a dye is the only answer. Have the shop evac and recharge the system adding a dye. After a couple weeks take it back and they will look for the leak using a special light designed for the dye.
 
  #4  
Old 06-02-03, 08:32 PM
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A typical shop will leak test, evacuate and charge your system. Even though you have a very small leak, they will leak test it and tell you that they found NO leak. Then they will proceed to charge it, etc. Afterwards, your leak will continue to leak, even faster than before (as time passes on). By the way, you just spend a fortune doing the above.

Many shops will not change o-rings where the leaks usually occur. To get around this, they will tell you they will leak test, knowing in advance that they will not find a leak. I'm not sure why they don't want to change o-rings, but I will guess it is profit margin related stuff.

You must find a reputable shop that you trust to replace the o-rings. As someone above mentioned, the compressor exhaust o-ring is a common failure point. This is where the pressure is extremely high in the system, and the o-ring often just gets blown into pieces and blown down into the system, causing still more work for the repair job.

Now for the big news. Many shops will NOT repair an r-12 system. They will tell you over the phone that they will only convert it to 134. This is partly due to the high cost of fallout if the car still leaks after the pricy repair. No shop wants to have even one of those customers. It's just bad for the customer and the shop no matter how you look at it.

If you are serious about repairing it instead of converting it, start asking your freinds which shop 'can' and 'will' do the work you want done. Save up several paychecks to pay for the r-12 and labor. After replacing the o-rings, the system will be (should definately be) fllushed out with special solvents made for that purpose.

In the end, you will need:
1. Recovery of existing r12 in system, (you won't get to reuse it even though the law allows for it; it's just not a common practice) .
2. Flushing of system components, (i.e. evaporator, condenser).
3. New o-rings installed.
4. New orifice tube (or equivelent).
5. Perhaps a new accumlator (or filter drier depending on style of ac you have). It is strongly recommended.
6. Pull a vacuum. (and check for vacuum leak)
7. Charge the system with correct amount of r12 and oil.

Then it should stay cool for years to come. Keep in mind that if you wreck your car, you just lost a ton of money on the a/c system. And depending on your car, a few car repairs may require you to evaculate the system to be able to effect repairs to other parts of the engine. What is r12 now adays, $50 for a 12oz can? And you need how many cans?

Good luck, whatever your path.
 
  #5  
Old 06-03-03, 05:53 AM
Joe_F
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Bring it to a few shops and get some estimates. Ask for what the problems are in writing. Then compare.

As noted, it could be just about anything from a lunched compressor to a 50 cent O-ring. And unfortunately, when they see BMW, you're going to pay .

At minimum: New o-rings gaskets, electronic leak check and recharge to whatever refrigerant is going to be used.
 
  #6  
Old 06-03-03, 02:26 PM
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Ugggh--- hey, thanks for all the thoughts on this everyone... I have a pretty good idea of what to expect now.

Sounds like I'm stick and somewhat at the whim of the shop. I hate it! So I'll go get some quotes and start talking to some shops to see what they say.

This whole thing is beginning to be a bummer :-(

aaron
 
  #7  
Old 06-03-03, 04:38 PM
Joe_F
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BMW always stood for "Broke My Wallet" .

Lackluster vehicles, I never liked 'em .
 
  #8  
Old 06-03-03, 07:25 PM
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"Break My Wallet" indeed...

$40 for a stupid 2 foot section of rubber fuel hose I had
to replace last year... It had a special right angle
bend on one end. I guess that's worth the $38 premium :-(
Plus, it has a pretty BMW logo stamped all over it.

I should have gotten a longer piece from the
local parts store, wrap it around some
stuff to accomplish the same, and get it done for $2.

sigh...

on the contrary, I've spent less time and money on fixing
the BMW compared to my 84 Toyota whose parts are far
cheaper. So I guess it evens out...

another sigh...

aaron
 
  #9  
Old 06-04-03, 02:29 PM
Joe_F
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Unless the parts store had the correct high pressure hose, you would have also caused a safety and fire hazard. You did the right thing.

Everything from the valve cap to the engine on a BMW comes with a premium without the premium quality, so that's why I avoid 'em . Most models are also butt ugly in my opinion. I am duly unimpressed to find most BMWs up until recently had crank sunroofs. LOL. Cheap!

Foreign cars of most vintages soak you when they get old. Parts get more expensive to make/source, they fit less, have to be stocked in fewer locations and the sources for them dry up. This is where domestic cars rule .
 
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