Whining over BT and a quick fix

Botus

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Noticed about 26 months after new AC condenser, that the horrible low speed whining noise is back.. Sounds like the gearbox is failing... But having been here before I now know its really a variable compressor AC induced irritant, when its low on gas.

AC works but 0 to 20mph slowing, stopping, accelerating in town work is this hideous, worrying, nasty racket that goes up and down like a worn box. Popped in to see a local Jag garage I know to ask if we can top up the R134A gas, all 1.3kg of it in mine. I said is whining lake a bugger and he confirms "that's what they do when low on gas", but will have to drain, check and completely refill like a grown up as that's the way the machine works...

...GREAT !!!

After I got over the 50 mins that will take, I thought OK so at least I'll know what it had (quite interested to know, and that he really put in 1.3kg) as its always been pathetic before and post the new AC condenser. Remarkable when a 500g or something set up in a 1.6 Ford focus gives ice cold air in the peak of summer !!!
Filling was incredible seems to put 1.3kg in less then 3 mins ? is that possible ? they thought it normal coz of the vac it had.

And that's when the silly paper ran out on the printer so I get no record of what it had, or what really went in

...GREAT !!!

Then as I was handing over the money, I got an important call and went to take it. And stupidly at one point I moved close enough the car took over via BT (bluetooth) and I lost the call and confused the car.... It was stuck in a call that didn't exist, that killed the radio, killed the rear AC controls (coz merc don't understand how a can bus set up works) and I couldn't cancel.

Key Out - Comand stayed on.
Comand OFF - Comand stays ON,
Tried to Kill the Phone within Comand menus - Greyed out.
Disconnect the Phone's BT via its menus - Car still believes its in a Call.
Turned off the phone - Car still believes its in a Call.
Made a new call - Car still thinks its on the original call and isn't picking up in the car, its all phone handset

...GREAT !!!

Wonder where the fuse is... can't be arsed...
Stick Diagnostics on it NO faults.
Think about the Battery don't want to fight it that much and have two to phaff with anyway

.. GREAT !!!

Then had a light bulb moment if I pull the BT Puck that should make it think about life
and it does... stupid car

AC is now quiet yet similarly pathetic ... way to go Mercedes on both incompetent points !!!
 

mattkh

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Thank you for this great and informative account.
 
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Botus

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Thank you for this great and informative account.

thanks, its why I bothered to write it.

alerts to a cause many unaware of, confirming twice (via experience and a garage agreeing) a nasty worrying whining noises - can be only the need to top up AC
gives a quick fix for older cars (with cradle handset) where the car muddles its BT set up and will flatten the battery to zero without intervention
posed a question I would like help with re how fast a car refills its AC gas with modern equipment.

I didn't place in this forum it was moved
 

Mr Greedy

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I had my w212 regassed yesterdayafter fitting a new condenser. I was very surprised looking at the Valeo Tech data sheet that the w212 takes 590g of gas, and the w211 takes 1100g I think it was!

It took a similar amount of time to refill and circulate by the tech to check it was working.

Remember, they fill the system from a vacuum, so I'm not surprised the gas can be guzzled in initially very quickly.

I'm going to check the resting system pressure in a bit and I'm looking for the 4.5 bar I had last time I had it gassed.


(After that and the speed of pressure drop, I knew it had a leak so had the system emptied and ran without aircon for a bit before I replaced the condenser)
 
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Botus

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I think
small cars is about 600g
my 3.0L omeba was 900g
my twin evaporator (rear ac) is 1200g (or 1300 - forgotten)
 


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