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1999 SL500
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49 Posts
Discussion Starter #1
WTH!!!! Sitting in house tonight and heard loud explosion with a long hisssssing sound afterword. Went out to garage and found it full of R134a from the 94 SL.!! It had been parked for a little over an hour when this happened. It looks like the large hose on the drivers side and coming from the back of A/C compressor & going back to the firewall burst. Appears it was rubbing or wearing on the bottom side of where it comes out from under the engine.

I do a lot of my own work but am not real familiar with A/C on these things... does anyone have any advice on how easy or $$$ this is to repair and what parts may be needed or is this something better left to the professionals??? Its been HOT here lately... 106 today and not much outlook for any cooler weather soon.

THANKS for any help!
 

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1987 560SL Gone but not forgotten! & 1999 SL500 For Now
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745 Posts
When I blew a high pressure hose in my old Benz I found a local AC shop that would do the needed repairs. Perhaps obvious to others, but this was the first time I was introduced to 'rebuilding' a hose instead of getting a new one from Mercedes. This tech removed the burst hose, ordered the same guage, etc. hose from a local supplier, cut the hose fittings off the old hose and reinstalled them in the new hose. This worked out to be about 75% less than the new complete part from Mercedes. When I sold the car 6 years later, that hose was still doing it's job. Good luck with yours-
 

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2009 S550, 1973 Avanti II, 2008 Silverado LTZ
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I know the exact spot you're talking about, and it's a terrible design. There should be a stand off of some sort there, but instead they have a hard plastic sheathing around the hose where it's pressed up against the left head. It's obviously going to wear there, and eventually through the plastic and into the hose.
Not their best design!
 

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1999 SL500
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49 Posts
Discussion Starter #5
Thanks for your help. First, I'm going to see if there's someone around here that can do the hose repair as Bob suggested and if not then I'll order one and put it on myself. Again
THANKS for all you guidance..one more thing... will it hurt anything to drive it some..without any refrigerant or oil in the system, if I leave it (A/C ) turned off???
 

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Departed 1998 SL500 (and the Pano is in Bogota)
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You should not have problem driving it as the compressor will not be running.
 

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1987 560SL Gone but not forgotten! & 1999 SL500 For Now
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Thanks for your help. First, I'm going to see if there's someone around here that can do the hose repair as Bob suggested and if not then I'll order one and put it on myself. Again
THANKS for all you guidance..one more thing... will it hurt anything to drive it some..without any refrigerant or oil in the system, if I leave it (A/C ) turned off???
You're not going to hurt anything by driving the car. As to repair strategy,
you've actually got 3 choices, Repair, Rebuild, Replace in the order of least expensive to most-

Repair-Often, hoses of this type can be repaired/patched and work well for years. Have an AC pro evaluate it for you.

Rebuild- Try googling on the term 'auto ac hose rebuilder ...' where the last term is the closest town, city, etc. You should be able to find a rebuilder local to you.

Replace-Open wallet, spend large

If this were my car, I'd first try to confirm why the hose burst in the first place; wear, heat, overfilled, system blocked . Next I'd have the hose evaluated for either repair, rebuild or replacement. Next, I'd look at replacing the receiver/dryer and expansion valve. Last, re-fill the system if you're sure the original burst was not caused by a block in the system. You'll be good to go for a 100K miles and be cool along the way. Good luck
 

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1996 SL500 - Triple Black
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51 Posts
exact same thing

I had the same hose burst at the same location under identical conditions.

I considered putting a splice between the two pieces of hose.....you can get it from Auto Zone for $7. However, I plan on keeping my car so I decided to just replace the hose and a/c dryeralong with the o rings. The cheapest I could find was $300 on line for that hose. I'm going to try and evacuate and charge the system myself. Just bought a vacuum pump, manifold gauges, and R134a. I'm just waiting for time to do it all now. Hopefully I'll remember to come back on here with the final disposition of it. Wish me luck!

Tata,
Tom
 

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1999 SL500
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49 Posts
Discussion Starter #9
I had the same hose burst at the same location under identical conditions.

I considered putting a splice between the two pieces of hose.....you can get it from Auto Zone for $7. However, I plan on keeping my car so I decided to just replace the hose and a/c dryeralong with the o rings. The cheapest I could find was $300 on line for that hose. I'm going to try and evacuate and charge the system myself. Just bought a vacuum pump, manifold gauges, and R134a. I'm just waiting for time to do it all now. Hopefully I'll remember to come back on here with the final disposition of it. Wish me luck!

Tata,
Tom


Thanks, for the help !!! Found a repair shop here in town, it goes in Wednesday and they are going to repair hose/recharge and replace the dryer. Good Luck with your's Tom!!
 

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Greek God of the R129
SL500-500SEL-190E
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I was also worrying about that.
As preventing medicine.
When I worked on the a/c.
I squeezed a piece of radiator hose, between the a/c hose and the engine. ;)

Regards,
aam.
 

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1999 SL500
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Discussion Starter #11
I was also worrying about that.
As preventing medicine.
When I worked on the a/c.
I squeezed a piece of radiator hose, between the a/c hose and the engine. ;)

Regards,
aam.
That's a great idea Albert !! I had no idea how BAD the A/C hose rubs in that area, and I will make sure I do what your suggesting after I get it back from the shop.
THANKS!!!
 

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SL55, 300SE, GL450, Daytona 955i
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Oddly enough I replaced my hose due to the same damage last weekend, the hose blew up 3 years ago, becuase the engine sliced it open...

BTW, this is a common problem, not because the poor design, but it's a side effect of a collapsed engine mount, as the engine sits an inch lower, and minimizes the clearance for the hose between the head alloy and frame...

As mentioned above, I drove the car for 3 years with the new hose in my basement, and never replaced it... until last week, when I decided its too hot to stay without AC, so I fixed it.

in details, for the upper end, near the fuel cooling end, you need 2 wrenches: 27mm and 1 1/4", lower end, you need 27mm and 7/8", and the third middle end near the compressor, you need deep socket 10mm, and torx T-something.

Upper and lower ends are accessible from above, but the compressor end needs to be accessed brom below...

final word of wisdom, fix your engine mounts before this hose... R134a is relatively expensive if you blow the new hose again...
 

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'95 500SL R-129 - '96 500SL R-129 - '98 ML320 - '98 CLK320
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haha-mine went just went last week-ordered a used one and had it installed. Have engine mounts too, but will replace when I get round to it. I just wrapped the replaced hose where it gets close to the engine and zip tied it so it no longer touches for now.

My question is the oring at the fuel cooler.
When the mechanic re-installed it-he said there was no oring, but I find that strange.

Perhaps you can let me know if there was one and he dropped it into the engine by accident or there really is none where the suction hose meets the fuel cooler. It seems fine and I get cold air, but just want to be sure.

(location is at the top just behind the low pressure nozzle - oring part number would be awesome so I can order it.)
 

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SL55, 300SE, GL450, Daytona 955i
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each end has a green O ring, and the compressor end has 2 black X type orings. dealer is your best source for these.

keep in mind that the hose gets pinched while the car is moving and not standing still, particularly in between shifts, when the entire engine weight moved by the massive toque jerks sideways, and lay on nothing but the poor hose...

the hose is never piched standing still, regardless of how bad your mounts are...
 

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Departed 1998 SL500 (and the Pano is in Bogota)
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I was also worrying about that.
As preventing medicine.
When I worked on the a/c.
I squeezed a piece of radiator hose, between the a/c hose and the engine. ;)

Regards,
aam.
:thumbsup:

Thanks for the reminder, I went to check mine today : Caught it just in time as the plastic guard is just about worn through. Put a piece of old radiator hose on it.
 

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Greek God of the R129
SL500-500SEL-190E
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8,391 Posts
each end has a green O ring, and the compressor end has 2 black X type orings. dealer is your best source for these.

keep in mind that the hose gets pinched while the car is moving and not standing still, particularly in between shifts, when the entire engine weight moved by the massive toque jerks sideways, and lay on nothing but the poor hose...

the hose is never piched standing still, regardless of how bad your mounts are...
When I removed the compressor, I reused the X type rings.
For me it was not a big deal....
If they hold, they hold. ;)

That was three four years a go? Lol.

Regards,
aam.
 

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Greek God of the R129
SL500-500SEL-190E
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8,391 Posts
:thumbsup:

Thanks for the reminder, I went to check mine today : Caught it just in time as the plastic guard is just about worn through. Put a piece of old radiator hose on it.
Ray,
She didn't blow the hose, but I saw the tightness, so it attracted my eye. ;)
(Cheap fix.)

Regards,
aam.
 

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1999 SL500
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49 Posts
Discussion Starter #18
UPDATE: Took the SL to shop this morning and they called and said it was ready, I picked it up just before they closed. On the way home the a/c never really got very cold and I pulled over and the compressor is clicking on then off, then on then off..... they repaired hose / replaced dryer, evacuated and recharged the system. I will have to take it back to them in the morning...any ideas on what it could be....??? Was working fine before the hose ruptured.
 

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02 SL500 SA, 03 Mercury Marauder, 89 Mercury Grand Marquis Colony Park
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131 Posts
I am guessing you mean it cycles off and on quickly? It is normal for the system to cycle but not quickly.

When I first charged my system I had asked for info on the system capacity and was given the wrong capacity, 2.2lbs. if I remember correctly. Eventually I saw the sticker under the hood. It did not catch my eye at first as it gives the charge weight in grams and most vehicles in the US show the fill in Pounds and ounces.

With the two plus pounds, the system cycled too quickly and did not get cold enough. This led me to find the sticker somehow. I recycled the 134 re-vac'ed the system and installed the correct amout of R134, about 1.6lbs?. It runs perfectly now. Did cost an extra hour or so between finding the sticker and performing the operation.

Too little charge would also cause the same symptoms. If they are pros, the ac manifold gauges should tell them the story. I am making the assumption here that they checked for leaks before and after the charge. Well if it has a significant leak it will be even worse in the morning, maybe not even cycle on.

Jay
 

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Greek God of the R129
SL500-500SEL-190E
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UPDATE: Took the SL to shop this morning and they called and said it was ready, I picked it up just before they closed. On the way home the a/c never really got very cold and I pulled over and the compressor is clicking on then off, then on then off..... they repaired hose / replaced dryer, evacuated and recharged the system. I will have to take it back to them in the morning...any ideas on what it could be....??? Was working fine before the hose ruptured.
Under charged, or bad sensor, wiring, etc.

Regards,
aam.
 
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