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I was looking at the amount of work I need to replace these parts :
Just got the special order delivery date and prices. All genuine MB.
My local price is typically +25 to 30% above USA price.
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This year is already almost 9th year old my car is. So it is coming close to my 10th year all rubber hoses and plastic begone program, here : https://mbworld.org/forums/e-class-w...tic-pipes.html at post #3 I have the list on excel.
I never yet included the 3 refrigerant hoses which are at hottest engine bay zone, for 10th year program. Never thought about it till I mess around with it last 2 weeks.
Since replacing the o-rings at hoses end is as much work as removing the hoses, I might as well renew those 3 hoses.
I took a price peek on the internet, all these 3 hoses if in my country, would be easy US$600 and while in USA would probably be US$400 - US$ 450 .
If I do replace 1 year sooner this 2023 ( 9th year ), these 3 hoses would be technically more expensive ONLY by 10% . Price divided by 10 years service life.
Me at the tropics is at a more disadvantage than a 4 seasons countries, as my under hood temperature is very hot all year round.
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The 4th hose ( # 250 , I did not show its P/N) I will not replace for now, yet and may serve pass the 10th year target I set.
It is also the one with IHX ( internal heat exchanger ) and its US$300 in UK Ebay and for me locally it would be US$400 ish.
This hose-pipe set operate at much cooler temperature for the usually hot liquid line ( HP side ) hose region.
The hot liquid R134A get cooled by the IHX and mainly 80% of this hose/pipe set is in secondary cooler area of the engine bay towards the EVAP.
When I do renew the 3 refrigerant hoses, I would remove the compressor to drain its oil, so that I can replace it with new oil, supposedly 20cc/ml I can get.
Without the AC compressor, I can then access the oil cooler water hose with ease. Might as well replace that hose too .
Too bad only oil cooler hose ( no 1 ) I can replace. The gasket ( no 2 ) is not possible to replace unless I remove engine mount base....YIKE !!!!!!
Damn...... Damn...
I wonder how would M276 3.5 NA component density would be at the side and above the AC compressor ?
My turbo lower region and the aftercooler pipe is getting in the way and under the compressor is the tranny oil cooler lines (2).
ASK : Anyone with earlier 2009 - 2013 W212 ever had issues with the R134A hoses or its o-rings , so far ?
Thanks
Hi Surya, attached is the bulletin for the collapsed hose. I came across that bulletin, and I am still suspicious about the suction hose on the W211. I have not concluded if the problem is the hose or the ECV.
Have you read/seen a damaged suction hose for the W212? I have the infrared thermometer to evaluate these kind of things, but sister's W211 is not close by and she is not driving that much to notice the AC, not optimal cooling.
Recently another forum member had an issue with his W166 suction hose (same M276), but I think it was leaking though not clear if through the Schrader valve or else.
I only hang out at W212 MBWorld, so far I never yet seen W212 suction hose failing at its inner lining.
It is expected, no hose will last super long time, it is a wear and tear item.
I seen more often diesel fuel hose internal portion/layer swelling and making restriction, there is no thin inner liner in those diesel fuel hoses.
The MB service bulletin is 2009, but does not tel which car model. I hope its not a BIODEGRADEABLE HOSE like the MB of 1992 to 1997 biodegradable wire harness hahahaha.
I think MB have ID-ded the refrigerant hose manufacturer/s which possibly only 1 or 2 brands, so no vehicle model/s mentioned.
Below is from an old car. 1996 Toyota Land Cruiser. Video is 2020 and assuming the hose was from new untouched, it is 24 years old when it inner liner collapsed to that extend...LOL, awesome service life !!!
AC suction hose inner liner collapse will take time, so if car is say 10 years old or more, its OK and acceptable and probably consumers won't make a fuss.
My Toyota radiator hose develop a minor tear at year 10, same with my Ford Fiesta heater hose at year 10.
My MK2 Supra power steering hose simply exploded hahaha, while car was under 4 years old.
I've owned a number of 25-30 year old high mileage (250K+) cars with their original AC hoses, no problems. replaced more than a few radiator and heater hoses at those ages.
The AC compressor removal will be giving me another good opportunity to replace the turbo feed oil hose/pipe assy.
This pipe-hose assy location is "hidden" by the AC compressor.
This process will allow me by year 10th, to save some money for RIGHT side turbo same pipe-hose assy as I can study the LEFT side one on my own time.
I can then buy the hose only from a good hose brand as it is simple straight one without any special bend, and those 2 hose clamps do not need special crimping like most other hoses W212 uses.
Only the O-ring #160 and metal gasket #170 are the other need-to-replace items, for RIGHT side turbo.
I got all 3 HVAC hoses, finally arrived from Germany.
Desiccant filter drier too.
They all already come with their respective o-rings, so now I got quite a few spare o-rings because I thought they never come with o-rings ., but o-rings are cheap and would be handy.
I was imagining on how I could plug off my HVAC lines/system and fill it up with nitrogen when I replace these new hoses.
I do not have the special plugs.
So I bought some balloon to simulate it as a "plug"
Below is a balloon pairs I injected with gas form R134A. This is 72 hours old. It has loss R134A approx 50% only, not bad.
1st and 2nd day, both have cable tie as extra clamping. The red electrical tape is there to protect the o-ring so that I do not damage it, as cable tie has those friction teeth.
End of 2nd day I cut the cable tie on the blue balloon. With the cable tie cut, I did loose more R134A on 2nd to 3rd day. So the cable tie does help to seal , from a better "choke".
The plan is like this :
After R134A evacuation done, light vacuum to 600 microns. STOP.
And then run 2-3 psi constant running nitrogen into both LP and HP service port, while disconnecting the 2 hoses below : These 2 hoses are where the HP and LP service port are located.
- Disconnect fat suction LP hose of compressor, at the compressor side. The side of the hose to its interconnect ( IHX - Internal Heat Exchanger ), I shall leave it as is.
- Disconnect thin HP hose from condenser, at condenser side. The side of the hose to its interconnect at IHX, I leave it as is.
When these 2 hoses are already disconnected, the running nitrogen 2-3 psi above ambient will not allow ambient air to enter my HVAC system which by now is the EVAP and hoses + alu pipes to EVAP left,.
Install the balloons on both hose end of HP and LP hoses.
Since I work on my own sweet time, me doing compressor removal to re-balance new oil, replacing refrigerant pressure sensor, replacing 3rd hose which is from compressor to condenser,
all will take a few days. So the nitrogen leak test on the hose is a confirmation that those balloon as plugs is good enough for more than 48 hours. Everyday I can inject more nitrogen
to the balloon sealed system, so no need to worry of moisture laden EVAP and its related hoses + alu pipe.
I will do all these work probably late July 2023.
I still am waiting for the rolls-royce of vacuum hose, hand carried from USA by my friend and some other HVAC stuff. https://www.trutechtools.com/Accutoo...Evacuation-Kit
This will not only cut down the vacuuming time to my target <200 micron , without this hose I can never hit below 200 micron even after 24 hours non stop vacuum,
I already tried but with current 9 years old filter drier. New filter drier should help me shave off another 50 microns.
The drier I can make my system, the colder my HVAC gets.
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Here is a result of me cleaning & trying to catch some old oil of my compressor using Emerson EK series filter drier.
Its very time consuming, very............ and result is not worth its time for only 10cc of compressor oil I managed to "catch" and re-balance.
The better ACID test would be this type : https://www.nucalgon.com/products/to...acid-test-kit/
and this : https://ph.parker.com/id/en/product-...orlan-test-all
But that is for commercial HVAC dudes which have access to oil collection port hole of their compressor and at least 5cc of oil to be extracted, with ease.
My test kit is easy push to leak out R134A at LP service port for 2 seconds. Since R134A is mixed with compressor oil, there will be a bit of oil extracted too doing that.
Compressor Oil trapping and cleaning. 7th June 2023.
I spent total 4 hours of circulating the R134A ( with its oil ) to catch its oil using Emerson EK-052 Filter Drier.
This process also remove acid from the oil and dry the R134A and the oil too.
R134A itself is allowed to have water moisture at a very low degree as set by standard ARI-700.
If you take the moisture indicator out of the system, within minutes it will turn yellow aka WET.
This moisture indicator is a standard item installed on commercial HVAC system. I wonder why car OE are so azz-hole and not
install this as standard. I will pay if there is such an option to include Low side refrigerant pressure sensor and also refrigerant temperature sensor at High Side,
as found on W220 S430 as early as 2002 ( temperature sensor ).......DUGHHHH !!!
My Mentor Tom Lech told me to install this moisture indicator during my oil cleaning/conditioning, otherwise the goal of having a dry system can never be proven and no amount of work I do is
worthwhile if I can't confirm that my system is super dry to at least lower than 75PPM.
1st time oil + R134A conditioning, 7th June. Total turnover of R134A I circulated via the Emerson Filter Drier is easy 800 grams . My System is a 590 grams system.
This MasterCool refrigerant sight glass internal volume is about 21cc of refrigerant if at 80% full and R134A specific gravity in liquid form if at 45-50Celsius after the condenser, is approx 1.1 or 10% heavier than water.
So 21 x 1.1 = 23.1 grams of R134A per 1 time I can fill up this inspection sight glass to 80% capacity. I need the 20% to make R134A in gas form when I return it to SUCTION/LP side, or else my
compressor will get liquid hammer and be damaged.
Yes, improved . The compressor oil is now much cleaner.
However, the amount of oil I managed to trap is very disappointing, only 6 grams of PAG 46 or Denso ND-8.
This oil has specific gravity of 0.99 of water, so basically we can call it equal to water.
The weight of the drier above is after I heat dry and I vacuum down the filter drier to under 200 microns.
I need to get rid of all else except trapped compressor oil. Compressor oil vapor pressure is not low enough for a vacuum pump to evaporate it, even at 50 microns.
I then by 9th of June decided, to do 2nd RRR and use a much bigger filter drier EK-304. And this time I will use HP port as recovery port, where there is more oil than at LP side.
I got 4 grams of compressor oil from just 1 session, but it is a total R134A recovery part of the RRR, not a circulation type job like 7th June.
So I have to fill up ( re-balance ) 10cc of ND-8 oil to replace the captured 10 grams. I use by weight measurement, much easier.
Now , it is time to remove any air molecules in the oil. Surprise surprise, the amount of air trapped in oil is a lot !!!
Air trapped in oil also means water moisture.
At 60 microns I am still getting explosions which means air and/or water moisture, as seen on the tablet graph, those spikes.
Doing this will reduce the final vacuuming time in the car HVAC system, as when the ND-8 PAG 46 oil is mixed with refrigerant, to vacuum them dry as a mixture is more difficult.
With now my HVAC system overall drier, I can pull vacuum down to 229 micron. My 1st RRR of April took me 9 hours and I gave up at 378 microns.
End result of 2nd RRR of 10th June 2023
Initially I thought these are dirt, but they are actually bunched up bubbles
05-11-2023, 11:53 AM
. Price divided by 10 years service life.
I have the infrared thermometer to evaluate these kind of things, but sister's W211 is not close by and she is not driving that much to notice the AC, not optimal cooling.
., but o-rings are cheap and would be handy.
. I will pay if there is such an option to include Low side refrigerant pressure sensor and also refrigerant temperature sensor at High Side,
