AC working but not really cold
#1
Super Member
Thread Starter
AC working but not really cold
2011 E350.
Not really educated on the AC system except for adding refrigerant. Pulled engine from CLS so can perform basic stuff mechanically. Reading up here by searching this morning.
Fiance tells me that driver side blowing lukewarm air while passenger side colder. I think low refrigerant so attach a can. Add just a little bit is already in the Green. Currently at 50 psi in 100 degree AZ temp.
Going to take it for a test drive and pick up replacement cabin filter. Pulled current one and it looks good but haven’t replaced it since 10k miles and now at 40k.
Anything else that I can check? No codes on scanner.
Not really educated on the AC system except for adding refrigerant. Pulled engine from CLS so can perform basic stuff mechanically. Reading up here by searching this morning.
Fiance tells me that driver side blowing lukewarm air while passenger side colder. I think low refrigerant so attach a can. Add just a little bit is already in the Green. Currently at 50 psi in 100 degree AZ temp.
Going to take it for a test drive and pick up replacement cabin filter. Pulled current one and it looks good but haven’t replaced it since 10k miles and now at 40k.
Anything else that I can check? No codes on scanner.
#2
Super Member
Thread Starter
Tested in garage. No road test yet. What do you think?
Outside temp 96 degrees. Hooked up can with gauge to low port.
Started car, set fan high, temp down until it got to LO.
Psi initially at 48, compressor kicked on, after 10min:
- psi 43 driver vent 53. Center vent 51. Passenger 53
changed fan to auto and temp to 72. After 5min
- psi 33 driver vent 54 center 49. Passenger 54
Is the psi supposed to drop over time or when fan turns up or down? I moved the settings back to LO and fan high and the psi went back to 43.
Outside temp 96 degrees. Hooked up can with gauge to low port.
Started car, set fan high, temp down until it got to LO.
Psi initially at 48, compressor kicked on, after 10min:
- psi 43 driver vent 53. Center vent 51. Passenger 53
changed fan to auto and temp to 72. After 5min
- psi 33 driver vent 54 center 49. Passenger 54
Is the psi supposed to drop over time or when fan turns up or down? I moved the settings back to LO and fan high and the psi went back to 43.
#3
MBWorld Fanatic!
As the inside air is getting cold there is less heat to remove so the low side pressure will drop. Some drop is normal during operation. More heat means higher pressure. Big drops in low side pressure could also be a sign that the txv is bad which can result in uneven cooling across the evap coil. But given the even temps between driver and passenger side, it doesn't seem like you have a difference between the sides. The side vents have a longer throw so they can differ in temp from center vents with a shorter throw.
Full disclosure - everything I learned about AC is from reading on internet forums so I am by no means an expert.
Full disclosure - everything I learned about AC is from reading on internet forums so I am by no means an expert.
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KEY08 (08-13-2018)
#4
MBWorld Fanatic!
^ What he said, and has taken me to school. Your temps seem good to me. I thought 50-55 was a good temperature base sign.
#5
Super Member
Thread Starter
Thanks guys. This started because she said driver side temp was lukewarm so wondering if me adding refrigerant fixed it. I am going to leave a temp gauge in the car and road test it now that you explained the psi drop. Thanks!!
#6
Super Member
Thread Starter
Stupid question here as I am reading on how to be a doctor on the internet
i came across an AC Pressure Chart. It says psi should be around 50 at 90-95 degrees and lowers to 35psi at 75 degrees but that is ambient temp outside.
Is that only with the fan on high and temp set to coolest setting? I am thinking that I could probably add a little more refrigerant with the readings above. Of course I am reading the psi from the dial on the disposal can stuff $40 from autozone so how accurate is that.
I am not doing anything like that until I roadtest and take many more interior temp readings over time.
i came across an AC Pressure Chart. It says psi should be around 50 at 90-95 degrees and lowers to 35psi at 75 degrees but that is ambient temp outside.
Is that only with the fan on high and temp set to coolest setting? I am thinking that I could probably add a little more refrigerant with the readings above. Of course I am reading the psi from the dial on the disposal can stuff $40 from autozone so how accurate is that.
I am not doing anything like that until I roadtest and take many more interior temp readings over time.
#7
MBWorld Fanatic!
Stupid question here as I am reading on how to be a doctor on the internet
i came across an AC Pressure Chart. It says psi should be around 50 at 90-95 degrees and lowers to 35psi at 75 degrees but that is ambient temp outside.
Is that only with the fan on high and temp set to coolest setting? I am thinking that I could probably add a little more refrigerant with the readings above. Of course I am reading the psi from the dial on the disposal can stuff $40 from autozone so how accurate is that.
I am not doing anything like that until I roadtest and take many more interior temp readings over time.
i came across an AC Pressure Chart. It says psi should be around 50 at 90-95 degrees and lowers to 35psi at 75 degrees but that is ambient temp outside.
Is that only with the fan on high and temp set to coolest setting? I am thinking that I could probably add a little more refrigerant with the readings above. Of course I am reading the psi from the dial on the disposal can stuff $40 from autozone so how accurate is that.
I am not doing anything like that until I roadtest and take many more interior temp readings over time.
In regards to possibly adding more, I would be careful as you can overcharge the system. I would wait until there is a problem that is clearly evident. These auto systems with all their sensors don't always get the comfort exact. If you think the system is underperforming while you're driving, I would adjust the temp and fan speed yourself (taking it out of auto) so that you can get the response you need.
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#9
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1922 Ford Model T / no OBD
http://www.mercedesmedic.com/ac-air-...le-codes-list/
Here is everything to troubleshoot the system. You already check for no codes, so now read the sensors (the link shows it on climatronic, but you need to use scanner on your model) and post the results here.
Read note on the site when to take the readings.
Here is everything to troubleshoot the system. You already check for no codes, so now read the sensors (the link shows it on climatronic, but you need to use scanner on your model) and post the results here.
Read note on the site when to take the readings.
#10
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Thread Starter
Kajtek, I was trying to get those readings but could not figure it out on a 2011 E350. My scanner is a Bosch bought at Autozone so maybe it isn’t capable? Thanks! Craig
#11
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1922 Ford Model T / no OBD
Getting scanner that reads everything on W212 is not easy.
I bought iCarsoft MBII this year and when it does tests and programming on W211 that were available only on SD before, it does not read some modules on W212. Don't remember if I could access AC and if I find more time, I will check it later. So if your scanner can't read sensors, you need to go to a shop who has one that does.
On the other hand the "hidden menus" on previous cars took some time to get discover and I wonder if going into engineering menu you might read the sensors on your command center, or AC display.
I hate dealing with software so will not go there unless life forces me to.
I bought iCarsoft MBII this year and when it does tests and programming on W211 that were available only on SD before, it does not read some modules on W212. Don't remember if I could access AC and if I find more time, I will check it later. So if your scanner can't read sensors, you need to go to a shop who has one that does.
On the other hand the "hidden menus" on previous cars took some time to get discover and I wonder if going into engineering menu you might read the sensors on your command center, or AC display.
I hate dealing with software so will not go there unless life forces me to.
#12
Super Member
Thread Starter
Thanks. I read how to access engineering menu so I will poke around.
Good news is that she says the air is cold now and I put a thermostat in there for her to manually take a reading on in case it drops. Will test this week.
Good news is that she says the air is cold now and I put a thermostat in there for her to manually take a reading on in case it drops. Will test this week.
#13
To the OP,
Please say that you have the proper gauges and know-how to read the high side, the low side, and make the proper adjustments according to your readings. Please tell me that you're not just doing the old "Pep Boys method" of buying a can of refrigerant (even if it is the right one) and fillin' her up. Diagnosing/addressing AC requires proper understanding of the system, and damage can result from fixes that used to work on an 84 Accord are applied to modern-car HVAC. And if you know all this, forgive me and press on!
Edward
Please say that you have the proper gauges and know-how to read the high side, the low side, and make the proper adjustments according to your readings. Please tell me that you're not just doing the old "Pep Boys method" of buying a can of refrigerant (even if it is the right one) and fillin' her up. Diagnosing/addressing AC requires proper understanding of the system, and damage can result from fixes that used to work on an 84 Accord are applied to modern-car HVAC. And if you know all this, forgive me and press on!
Edward
#14
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Thread Starter
Edward, I do not. I learned a lot from reading and watching many videos since I posted. Just being honest. I totally used the pep boys method and only added refrigerant with the can and gauge. I got lucky because air is cold now and I do intend to pick up a proper set of gauges.
#15
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Edward, I do not. I learned a lot from reading and watching many videos since I posted. Just being honest. I totally used the pep boys method and only added refrigerant with the can and gauge. I got lucky because air is cold now and I do intend to pick up a proper set of gauges.
#17
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1922 Ford Model T / no OBD
Having high pressure sensor in the car you don't need the gauges. I mean it is not bad thing to have them for advanced compressor testing, but even having AC filling gauges, I rather used car sensor than tap into high port valve, what opens possibilities for leaks.
#19
Kudos to you for the DIY approach ...how I've lived for decades. And it sounds like you're savvy enough to get the info and read up. All I am saying --and cautioning about-- is that some systems are more "particular" than others, having narrower operating parameters, while others are more forgiving, even allowing for a modicum of error, and have low consequences if one messes up. As already posted, AC will not blow cold if pressure is too high as well as too low; not to mention is a high-pressure system that needs to be heeded carefully. Tread carefully is all
Edward
Edward
#20
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14 550 sedan
No idea in detail how a/c works but have you tried a simple evac and recharge to the system? Sometimes that's all it needs. On my w211 I once had I think my heater control valve and one of the actual valve flaps go bad as well, which sounds similar to this issue in a way
#21
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1922 Ford Model T / no OBD
Point is that you can do full troubleshooting in the matter of seconds once you get proper scanner. On my W211 I replaced climatronic with one that can read the sensors, so I can do troubleshooting at 75 mph.
Why drop parts/refrigerant blindfolded?
Why drop parts/refrigerant blindfolded?
#22
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Thread Starter
Thanks everyone. Air has been working perfectly since I used the gauge from the $40 can and kept it within psi parameters above. Will have a proper gauge set for the next time but hers just needed a little juice and set to the right psi.