X218 aircon system pressure

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E55BOF

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CLS63 SB, SLK55, Cooper S, Triumph Sprint (Bike not Dolly...),
Doing some checks on the 2014 CLS 63 today, the iCarsoft check on the aircon pressure (must be high side) never rose above 10.2 bar (just after I cranked it down to 16 degrees from 20) and dropped quite quickly to about 8 bar.

It takes a lot longer, because it doesn't blow nearly as cold as the CLS 350's almost-instant instant Arctic blast, to get the temperature down. ISTR the W210's aircon, with built-in OBD, ran at something like 14 bar.

There were no fault codes. Does anyone know whether the pressure readings I obtained indicate the system is low on refrigerant?
 
I didn’t know you could measure the pressure with the Icarsoft, mine isn’t as cold as the wife’s car, so maybe have a similar issue.
Will check mine tomorrow.
 
Doing some checks on the 2014 CLS 63 today, the iCarsoft check on the aircon pressure (must be high side) never rose above 10.2 bar (just after I cranked it down to 16 degrees from 20) and dropped quite quickly to about 8 bar.

It takes a lot longer, because it doesn't blow nearly as cold as the CLS 350's almost-instant instant Arctic blast, to get the temperature down. ISTR the W210's aircon, with built-in OBD, ran at something like 14 bar.

There were no fault codes. Does anyone know whether the pressure readings I obtained indicate the system is low on refrigerant?
A generic reply would be that you are low on refrigerant. Rule of thumb is High side 2,5 times ambient.
so say 85F x 2.5 =212psi
Low side should be about 35 psi meaning that the refrigerant is boiling in the evaporator at about 30 dgf. (Brr cold )
Now with 10 Bar or around 150 psi its probably low on the high side, unless it was freezing cold when you tested the system!!

So first thing is to base line the systems and suck out the refrigerant and weigh it comparing it to the charge weight on the car's A/C info label.
If the system has air in it, a recycle will expel this incondensables that affect A/C performance .
When doing this I/We we always replace the two charge valve fittings for new.
MB ones area about $25 each on this side and a breeze to change .
Don't forget a new cabin filter and possibly a foaming coil cleaner for the evap' and condenser.
I use a product by Zep!
English country garden scent or Hospital like aroma.
The latter remind me of the the NHS or visits to the effing school dentist so I prefer & recommend the English Cottage garden aroma ! :eek:
Tuercas viejas
 
I didn’t know you could measure the pressure with the Icarsoft, mine isn’t as cold as the wife’s car, so maybe have a similar issue.
Will check mine tomorrow.
Mine's an MB II. The information is in the Aircon data stream.
A generic reply would be that you are low on refrigerant. Rule of thumb is High side 2,5 times ambient.
so say 85F x 2.5 =212psi

Now with 10 Bar or around 150 psi its probably low on the high side, unless it was freezing cold when you tested the system!!
Thank you for that. Is that the steady running pressure once the system gets into its stride, or the peak on initial switch-on? Ambient was 24 deg C / 77 F, which would suggest about 13 bar is the right ballpark figure, and ISTR the figure of 14 bar from the W210 too, which isn't far off. I'll top it up and see if it improves.
 
Just checked mine, it goes up to 210 psi down to 119 psi at constant 1500 revs set on 16 degrees, at idle it behaves the same.
Outside temp says 18 degrees on the car and 64.4 *F on Icarsoft.
 
Did the same check on the blue SB today; 14 bar, give or take, at max cooling at idle, so I'll just top up the red one until it's the same - no messing about putting 100 gm. in at a time and seeing if it's blowing properly cold.

The iCarsoft really is an excellent bit of kit.
 
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