AC Question
Thread Starter
Junior Member
Joined: Mar 2021
Posts: 44
Likes: 3
2003 E55 AMG
AC Question
Hi Guys,
The AC on my 03 E55 AMG has been acting weird.
It blows cold when driving on the freeway but when idling or in stop and go traffic the driver side starts to get warm. It doesn't get really hot but feels Luke warm.
I used the engineering menu on the AC to get some data
Idling:
Ambient Temp from IC: 40C
Engineering Menu:
1 In car Temp- 30C
2 Outside Temp- 29C
3 Heater core left- 79C
4 Heater core right- 40C
5 Evap Core- 13C
6 Engine Coolant- 96C
7 Refrigerant temp- 20
8 Not Sure what this one is - 69C
9 Not Sure what this one is - 01
10 Fan speed (??)- 95
Freeway: Was done about 3 hours later
Ambient Temp from IC: 34.5C
Engineering Menu:
1 In car Temp- 23C
2 Outside Temp- 22C
3 Heater core left- 34C
4 Heater core right- 34C
5 Evap Core- 2C
6 Engine Coolant- 92C
7 Refrigerant temp- 7
8 Not Sure what this one is - 45C
9 Not Sure what this one is - --
10 Fan speed (??)- 0
Let it Idle after the freeway drive and the 3 Heater core left temp crept up to 70 C in 2-3 minutes of idling.
What could cause the left heater core temp to go high during idle?
Also, why is the outside temp, as seen from the engineering menu, so different from the one shown in the Instrument Cluster ?
Could a bad engine fan cause this, the engine fan does not blow at full speed and is always pretty quiet. I did find burn marks/corrosion on the plug and have ordered a new one just in case this one goes out.
Any and all help would be appreciated.
The AC on my 03 E55 AMG has been acting weird.
It blows cold when driving on the freeway but when idling or in stop and go traffic the driver side starts to get warm. It doesn't get really hot but feels Luke warm.
I used the engineering menu on the AC to get some data
Idling:
Ambient Temp from IC: 40C
Engineering Menu:
1 In car Temp- 30C
2 Outside Temp- 29C
3 Heater core left- 79C
4 Heater core right- 40C
5 Evap Core- 13C
6 Engine Coolant- 96C
7 Refrigerant temp- 20
8 Not Sure what this one is - 69C
9 Not Sure what this one is - 01
10 Fan speed (??)- 95
Freeway: Was done about 3 hours later
Ambient Temp from IC: 34.5C
Engineering Menu:
1 In car Temp- 23C
2 Outside Temp- 22C
3 Heater core left- 34C
4 Heater core right- 34C
5 Evap Core- 2C
6 Engine Coolant- 92C
7 Refrigerant temp- 7
8 Not Sure what this one is - 45C
9 Not Sure what this one is - --
10 Fan speed (??)- 0
Let it Idle after the freeway drive and the 3 Heater core left temp crept up to 70 C in 2-3 minutes of idling.
What could cause the left heater core temp to go high during idle?
Also, why is the outside temp, as seen from the engineering menu, so different from the one shown in the Instrument Cluster ?
Could a bad engine fan cause this, the engine fan does not blow at full speed and is always pretty quiet. I did find burn marks/corrosion on the plug and have ordered a new one just in case this one goes out.
Any and all help would be appreciated.
Last edited by fruitsalt; Jun 22, 2021 at 12:07 AM.
MBWorld Fanatic!
Joined: Jan 2014
Posts: 3,973
Likes: 1,320
From: Republic of Texas
'99 and '05 E55 AMG
Sounds like an issue with the flaps in the dash that blend hot and cold air. If you have STAR, there's a diagnostic section that verifies flap operation individually.
Senior Member
Joined: Aug 2009
Posts: 348
Likes: 60
2004 E55 AMG / 2019 Audi Q7 / 1991 300TE
could possibly just be low on refrigerant. my ac was never that cold in the previous 2 summers I owned it, then this year on the first warm day i fired it up and it was blowing hot air on the drivers side and cool on the passenger. i bought one of those DIY kits (which has a gauge on it to tell you your level) and filled it up and it's been freezing me out since.
MBWorld Fanatic!
Joined: Jun 2020
Posts: 2,138
Likes: 871
04 E55 AMG (totaled), 07 S550 4Matic, 14 E63S
could possibly just be low on refrigerant. my ac was never that cold in the previous 2 summers I owned it, then this year on the first warm day i fired it up and it was blowing hot air on the drivers side and cool on the passenger. i bought one of those DIY kits (which has a gauge on it to tell you your level) and filled it up and it's been freezing me out since.
Senior Member
Joined: Aug 2009
Posts: 348
Likes: 60
2004 E55 AMG / 2019 Audi Q7 / 1991 300TE
yeh it didn't make much sense to me that low refrigerant would cause one side to go warm first but after looking into it, it's pretty common. If you hook the system up and it says you're in the regular range, then start looking elsewhere. but i'd start with the easy fix
