How often should A/C hoses be replaced? - Page 3 - PeachParts Mercedes-Benz Forum

torsionbar · #31 06-22-2017, 09:30 AM

Quote:

Originally Posted by HuskyMan

I'm starting on my A/C project for the 1984 300DT. I just had the A/C evacuated, the repair shop told me the system was low. I discussed the age of the automobile and A/C hoses with a local mechanic. He feels that at this age, all of the A/C hoses and O rings should be replaced.

Of course this is going to take a LOT of blood, sweat and tears plus $$$$$$$$. Can I get by leaving the old hoses in place? Or would leaving the old A/C hoses in place be an invitation for future A/C system leaks?

IMO the A/C hoses are like a pair of shoes. When to replace them depends entirely on their condition. Also depends on where you live, if you're in Hawaii and you use A/C a few days each year, or if you're in Florida and you need A/C nine months a year.

Does $20 of r134 charge it up enough to keep you cool through the summer? If so, I would leave them be, and simply recharge yearly as summer arrives. If a recharge only lasts a few weeks, it's time to replace.

Quote:

Originally Posted by Mxfrank

Don't buy a factory hose...take your old hoses to a shop that does pneumatic repairs, and have them rebuilt with barrier hose. The result will be perfect, at a fraction of the cost.

x2, this will be a much cheaper option than buying new hoses. It will also yield better results, as the rebuilt hoses will have proper r134 barrier hose that won't leak.

Replacement hoses from the dealer may not be made for r134, or may even be old stock that's been sitting on a shelf for ten years- you dont want that.

ROLLGUY · #32 06-22-2017, 10:37 AM

Quote:

Originally Posted by torsionbar

.............................

Does $20 of r134 charge it up enough to keep you cool through the summer? If so, I would leave them be, and simply recharge yearly as summer arrives. If a recharge only lasts a few weeks, it's time to replace.

x2, this will be a much cheaper option than buying new hoses. It will also yield better results, as the rebuilt hoses will have proper r134 barrier hose that won't leak.

Replacement hoses from the dealer may not be made for r134, or may even be old stock that's been sitting on a shelf for ten years- you dont want that.

Agreed about the NOS hoses=not good, rebuilt with fresh rubber is best.

"Does $20 of r134 charge it up enough to keep you cool through the summer? If so, I would leave them be, and simply recharge yearly as summer arrives. If a recharge only lasts a few weeks, it's time to replace."
The problem with this rationale is that when the refrigerant leaks out, so does the oil. We all know what happens to EVERY SINGLE ONE of these R4's when the oil is gone. Spending $20 and charging every summer is false economy. The only way to know how much oil is in there is to flush the entire system. One could also put too much oil in, and that is not good either. Again, why is there enough $ and time to do it over and over, but not enough time or $ to do it right the first time?

leathermang · #33 06-22-2017, 12:17 PM

Quote:

Originally Posted by ROLLGUY

..... "Does $20 of r134 charge it up enough to keep you cool through the summer? If so, I would leave them be, and simply recharge yearly as summer arrives. If a recharge only lasts a few weeks, it's time to replace."
The problem with this rationale is that when the refrigerant leaks out, so does the oil. We all know what happens to EVERY SINGLE ONE of these R4's when the oil is gone. Spending $20 and charging every summer is false economy. The only way to know how much oil is in there is to flush the entire system. One could also put too much oil in, and that is not good either. Again, why is there enough $ and time to do it over and over, but not enough time or $ to do it right the first time?

So true and so often forgotten by people...
""" false economy '''' for sure.... a short term strategy which will almost certainly cost WAY more in the long run. AND if one is cynical ...you can count on it happening at the very worst time... like hundreds or thousands of miles from home on vacation in the middle of Summer... ( that is not just some spiritual negativity attitude.. that is the time the AC is working the hardest... )..

ah-kay · #34 06-22-2017, 12:31 PM

Quote:

Originally Posted by ROLLGUY

Agreed about the NOS hoses=not good, rebuilt with fresh rubber is best.

"Does $20 of r134 charge it up enough to keep you cool through the summer? If so, I would leave them be, and simply recharge yearly as summer arrives. If a recharge only lasts a few weeks, it's time to replace."
The problem with this rationale is that when the refrigerant leaks out, so does the oil. We all know what happens to EVERY SINGLE ONE of these R4's when the oil is gone. Spending $20 and charging every summer is false economy. The only way to know how much oil is in there is to flush the entire system. One could also put too much oil in, and that is not good either. Again, why is there enough $ and time to do it over and over, but not enough time or $ to do it right the first time?

Rich, I hate to disagree. I always believe in 'Just enough engineering' and never 'while I am in there' mentality. Examples abound, just look at recent posts that some member over did it and caused all kind of problems, vacuum pump, lifters etc. I have 6 MBZ diesel and all are 30+ years old. I only service them enough to keep them on the road as daily drivers. You have seen a number of them and they are reliable and in good shape. Have I been stranded by them? Yes, on rare occasions but never anything that I did not do 'while I am in there'. I think it does not make sense to over do the car as you can never get it 'RIGHT' for a 30+ years car. The other shoe will drop when you turn your back to it.

Just my $0.02.

ROLLGUY · #35 06-22-2017, 01:23 PM

Quote:

Originally Posted by ah-kay

Rich, I hate to disagree. I always believe in 'Just enough engineering' and never 'while I am in there' mentality. Examples abound, just look at recent posts that some member over did it and caused all kind of problems, vacuum pump, lifters etc. I have 6 MBZ diesel and all are 30+ years old. I only service them enough to keep them on the road as daily drivers. You have seen a number of them and they are reliable and in good shape. Have I been stranded by them? Yes, on rare occasions but never anything that I did not do 'while I am in there'. I think it does not make sense to over do the car as you can never get it 'RIGHT' for a 30+ years car. The other shoe will drop when you turn your back to it.

Just my $0.02.

Well then, if you hate to disagree, then don't! :-)
I see your point, and understand that it does apply to many things. Automotive A/C is different, especially when a GM R4 is involved. The OP is free to spend as little or as much time and $ on this as he desires. Him not having the experience with auto A/C in general, and especially with these cars, will have a great impact on his wallet if the sound advice given by the experts is not heeded. I know that most if not all your cars have a Denso compressor, so you don't have the same amount of A/C challenges that most W123 owners have. I have had so many headaches with the R4, that I will not touch another one again (except to remove it and throw it in the recycle bin). I just don't like throwing $ at something that is a bad design to start with.
The same goes for the hoses. If they leak (and they do), they give the R4 a better chance to seize. I would not wish That on anyone.

leathermang · #36 06-22-2017, 01:30 PM

Quote:

Originally Posted by ah-kay

Rich, I hate to disagree. I always believe in 'Just enough engineering' and never 'while I am in there' mentality. Examples abound, just look at recent posts that some member over did it and caused all kind of problems, vacuum pump, lifters etc. I have 6 MBZ diesel and all are 30+ years old. I only service them enough to keep them on the road as daily drivers. You have seen a number of them and they are reliable and in good shape. Have I been stranded by them? Yes, on rare occasions but never anything that I did not do 'while I am in there'. I think it does not make sense to over do the car as you can never get it 'RIGHT' for a 30+ years car. The other shoe will drop when you turn your back to it. Just my $0.02.

There are some things which just beg to be replaced ' while you are in there'... I have preached for years that valve rotators and springs should both be replaced when one does the valve stem seals...as the LABOR to get back to there... is significant... and they are a ' wear ' item with a limited life span....
Some people will recognize your position as a practical and functional AS LONG as a person is good at determining what is most likely to need replacing and not stranding one or causing an accident....
However, Some people , having rescued or saved their 30 year old Mercedes may enjoy knowing they are ' taking care of business' while they are there... the essence of a '' labor of LOVE ''... and being prepared as best as one can be....

ah-kay · #37 06-22-2017, 01:35 PM

I changed out a R4 on my 83 300D. All I did was put a re-manufactured unit in there, changed out the recv/drier. It was about 3 years ago and it is still running good. R4 has it's short-comings. However, it is used in many make of cars and by many car manufacturers. It has to pass muster in my opinion. My other contention is that one unscrewed joint plus new parts introduces a potential new point of failure. My take is to just do enough to fix it, especially one is a newbie. The last thing you want is that you cannot button it back all together. That would be a huge mistake for a newbie.

I value your opinions but I beg to differ on this one.

ah-kay · #38 06-22-2017, 01:42 PM

There are things that need to be taken care of 'while you are in there'. A/C is NOT one of them as you do not need to peel off a layer to get to another layer. It is not an onion. A/C is just a linear circuit, nothing to it. I would never peach 'while you are in there' nor 'taking care of business'. I am pragmatic and practical. I know how deep is my pocket and what is my DIY abilities.

Again I value your opinions but I beg to differ.

funola · #39 06-22-2017, 01:43 PM

Quote:

Originally Posted by ROLLGUY

..............Automotive A/C is different, especially when a GM R4 is involved.
......

And the fact that you are selling a kit to replace the R4. Have you got the cracked bracket issue on your kit solved? It'd suck to spend all that money and labor to install the kit to have a non working system when the brackets crack.

leathermang · #40 06-22-2017, 02:34 PM

Quote:

Originally Posted by ah-kay

I changed out a R4 on my 83 300D. All I did was put a re-manufactured unit in there, changed out the recv/drier. It was about 3 years ago and it is still running good. R4 has it's short-comings. However, it is used in many make of cars and by many car manufacturers. It has to pass muster in my opinion. My other contention is that one unscrewed joint plus new parts introduces a potential new point of failure. My take is to just do enough to fix it, especially one is a newbie. The last thing you want is that you cannot button it back all together. That would be a huge mistake for a newbie.

I value your opinions but I beg to differ on this one.

When I was thinking about changing out my R4 to a newer style compressor.. i consulted with Trey Carlisle of Carlisle Auto Air in San Antonio... and he talked me OUT of that by saying what you just said... that the R4 has been used just fine in millions of cars and trucks.. HOWEVER, he also said (ten years ago ) that if the refrigerant was being changed to 134a ( with its higher working pressures and potentially less efficient oil miscibility ) (url at bottom) That one should look for a later built R4.. which was made to run the R134a.

He gave me the serial number of the newer R134a R4 compressors to look for when buying a reconditioned one... made to withstand the higher pressures.. Surely at some point all of the old ones will exit the system and no one need check those.. but that is in the archives somewhere..

In discussing what should or should not be replaced ( other than the slam dunk receiver dryer which everyone agrees on ) ... it is not logical or FAIR to ' newbies ' to use your own car example due to the number of uncontrolled VARIABLES.....
you might have gotten lucky... for instance no past owner or their AC Tech added oil to your system when it did not need it added... So you might be just fine not having done the whole , admittedly not fun, complete flush of the system... so that one knows the exact amount of ( the correct ) oil in the system...

They might not be as LUCKY.... and they would have to REDO a lot of expensive stuff if they were UNLUCKY... with regards to their car's history...

As long as there is good discussion about the different philosophies.. members can make their own decisions....

As to the assumption that taking it to ' pros ' will be a once and done.. I am sure that is not the case just from asking ' qualifying ' questions of garages in this area when I needed work on my pickup truck... So many are into the ' as long as it lasts through the one year warranty ' they feel fine about it.. and many small things can be left off the procedure which will still allow the ' fix ' to last that one year...

5.6 Oil and refrigerants - SWEP

ILUVMILS · #41 06-22-2017, 07:57 PM

Quote:

Originally Posted by leathermang

REALLY ????? You think the Dealership has no skin in the game... if something messes up which you can not or do not want to fix they are standing there ready to charge I don't know how much per hour to get you back on the road cool... so they have nothing to lose......and potentially something to gain if the dye does clog something.

This is a ridiculous statement, you sound paranoid....

ILUVMILS · #42 06-22-2017, 08:21 PM

Quote:

Originally Posted by leathermang

So you compare HAVING to OPEN up the container the Evaporator is IN... to just sticking a sniffer in the vent opening in the car ? I had a leak in my 81 wagon evaporator and it went off like a Christmas tree... I knew I had a leak in the big line across the engine.. it would have been $150 but if the evaporator had a leak the car was not worth fixing. ( steering needed fix also)

Interesting NONE of your techs OWN a sniffer... or you ?

If that is the case how did you get your opinion about ' too many false positives' ?

Who said anything about "HAVING to OPEN up the container the Evaporator is IN..." ??? Did you read what I wrote about using a bore-scope? They work great for inspecting evaporators (and lots of other non-AC related stuff). I'm glad your sniffer served you well on your '81 wagon, if it works for you and you trust it then stick with it

OK, some of my older guys DO own sniffers..........the batteries in them have been dead for years due to lack of use, but, FWIW I have used them. I just think they're unreliable and a waste of money, and my team of technicians all share my opinion.

I hope that answers your questions......

ILUVMILS · #43 06-22-2017, 08:32 PM

Quote:

Originally Posted by leathermang

......I got my opinions about the dye by doing a lot of reading on Aircondition.com and ACKits.com......

I got my opinions about the dye by actually using it a few thousand times over many years.........

leathermang · #44 06-22-2017, 09:43 PM

I also own a borescope....and I suggest you are blowing smoke up these people pants legs in your desire to be contrary. I stand by all my paranoid ( and practical physics based ) statements....
Does your borescope have an ultraviolet lamp on it ? and a filter to see the oil under that light ? lol

ILUVMILS · #45 06-22-2017, 09:44 PM

Quote:

Originally Posted by leathermang

..... dye, just like oil, can pool in low spots... you can not plan on it being evenly dispersed through the system....so Where you install it relative to where you develop a leak later may make a difference

You are apparently planning on enough dye making it to the evaporator.. and leaking in quantities sufficient to see at the bottom of the fins.. dripping off..
OR running out of the condensation tube under the car..... those expectations have real world problems associated with them...

OK, I'll try to keep this simple. At the end of your post you mentioned the "real world".........So, in the real world, concerning automotive A/C, the refrigerant oil mixes with the refrigerant. Since the dye mixes with the refrigerant oil, and the refrigerant oil mixes with the refrigerant, that means that the three ingredients are all mixed together. They all travel through the refrigeration circuit together. That's how the dye gets to the evaporator (and everywhere else) in sufficient quantity to be able to be detected.

AND, I've diagnosed many evaporator leaks using a UV light aimed in the direction of the "condensation tube under the car", or using the aforementioned bore-scope.

IMHO, this is as "real world" as it gets.......regardless of what you've read on your favorite website........