2011 e350 a/c not working. I took it to dealer in 2018, they recharged the system. A/C worked until July 2020. Took car to dealer 8/17/20, advisor stated system needs recharge with dye. I questioned why is a closed system needing recharge -where is the leak? Advisor insists car was diagnosed and even install an A/C update . They do not see a leak.. Scratching my head, What's up here.

Small leaks can be difficult to pinpoint. FWIW, the cost of a yearly re-charge is less than even the simplest repair. If the system works well during the warmer months I'd just keep charging it.....

thank you for your advice

What about the environment? jk'ing

What ILUVMILS said.

How many miles are on it? One of the best tools I have access to is an electronic freon detector. Works real good. Did dye get put in it? If yes, then you should see it next time you fill.

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Jim

zeggate, in 2013 the A/C was not working in our 1998 E320. Repair cost almost $4,000 to replace the evaporator, compressor, drier and expansion valve. The car is built around the evaporator so the dash must be removed to replace it … hefty labor charge. Apparently specific manufacturers' evaporators are more likely to fail than others, so it's pot luck how troublesome your A/C system becomes.

If the MB dealer is willing to recharge the A/C system for you that's the least expensive way to go, but your leaky system is harming the atmosphere. Environmentally-responsible shops will insist that the A/C system leak be located and repaired.

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Fred Hoelzle

Thanks to all for your input. I get it ,we should be environmentally responsible meanwhile their killing us with a virus that can be stopped with hand sanitizer ? ? I digress.

The dealer says they used a leak detector with a dye. If it needs recharging again the leak should been seen. Keeping my fingers crossed. At $325.00 per recharge I will have paid for a repair in about 11 more visits.

The stresses of life go on. Thanks again , Happy Benzing

LOL

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Jim

You, sir, win the Internet this morning. Excuse me while I go clean coffee from my monitor and keyboard.

To echo what others have already said in this thread, if it's taking 2 years to leak the charge out, the leak is likely too small to effectively locate. No automotive system is 100% leak free, and as they age you develop leaks and weeps at joints, rubber hoses, gaskets, and shaft seals.

Just as a personal example: My Honda has a very slow leak in it somewhere that has never been successfully located. Every year or two it needs a top-off, about 3-4 ounces of refrigerant. Total system charge is 14 ounces on that car, so taking 1-2 years to leak out that small amount means the leak is tiny. The dye may help, but even that's not a guarantee. My car has had dye in it since 2015 and despite gas still leaking, there's no dye trail anywhere that can be seen.

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Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Thank you . Points well taken. Enjoy

Ditch the dealer and just use r152a. Less than $20 to fill your system and it's environmentally friendly.

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1990 190E 3.0L

I've had slow hard to find leaks too. There are a lot of O-rings in that system and sometimes they hold up for 20yrs, sometimes only a few. So what I do is buy the sealant. I used this one last, worked great; amazon.com/dp/B086KYJSLG I used this to put it in; amazon.com/dp/B07FCFWXNQ along with some freon of course, which I bought a six pack or so of.
I think I spent like $70 or so all together and have plenty of freon left over.
That hose assy has a check valve in it so you don't need to have a can on it to read your pressure. Just use it like a a tire pressure gauge, pop it on, check psi. Mine likes to be on the higher end, I think it 45 psi? Likely due to it being hot where I live which is currently >100.
If it still leaks then you can use a UV light to look for it since the sealer has UV die in it. I have a UV light I got on ebay; ebay.com/itm/361959635949