Evap Temp Sensor, or Not?
08-25-2011, 03:51 PM
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1999 E320
Evap Temp Sensor, or Not?
Hey All,
My '99 E320 has been flawless for the past couple of years, but two days ago the A/C just stopped blowing cold air and so I'd appreciate any help as I have a new, longer commute starting next week. My first instinct was to check the refrigerant levels on the low-pressure port with my cheap gauge, which read about 72psi, which seemed high to me. I ran diagnostics and got the following values after two tests (about an hour apart):
1 = 75/78
2 = 76/80
3 = 94/76
4 = 94/76
5 = 116/118
6 = 177/190
7 = 05/05
8 = 87/94
Initially, I got a slew of fault codes, but I cleared them and then found EB1 419 and 459. After seeing the 5-bar high-pressure reading on #7 and realizing that it was at about the same level as the low-pressure side, I relieved some pressure from the low side until I got the gauge to read about 38F. At that point, I rechecked the values and reset the codes again, getting 4-bar for #7, while the 459 code disappeared completely.
After doing a lot of reading, I figured that I was looking at a faulty evaporator temperature sensor, but most of the posts I read mentioned that the air would be cool for a couple of minutes, after which the compressor clutch would turn off due to the faulty sensor. In my case, the clutch never engages at all, so I'm not sure if I'm looking at a faulty compressor clutch instead.
Any thoughts would be greatly appreciated, as I'd like to fix the car this week. Thanks!
-Mike
My '99 E320 has been flawless for the past couple of years, but two days ago the A/C just stopped blowing cold air and so I'd appreciate any help as I have a new, longer commute starting next week. My first instinct was to check the refrigerant levels on the low-pressure port with my cheap gauge, which read about 72psi, which seemed high to me. I ran diagnostics and got the following values after two tests (about an hour apart):
1 = 75/78
2 = 76/80
3 = 94/76
4 = 94/76
5 = 116/118
6 = 177/190
7 = 05/05
8 = 87/94
Initially, I got a slew of fault codes, but I cleared them and then found EB1 419 and 459. After seeing the 5-bar high-pressure reading on #7 and realizing that it was at about the same level as the low-pressure side, I relieved some pressure from the low side until I got the gauge to read about 38F. At that point, I rechecked the values and reset the codes again, getting 4-bar for #7, while the 459 code disappeared completely.
After doing a lot of reading, I figured that I was looking at a faulty evaporator temperature sensor, but most of the posts I read mentioned that the air would be cool for a couple of minutes, after which the compressor clutch would turn off due to the faulty sensor. In my case, the clutch never engages at all, so I'm not sure if I'm looking at a faulty compressor clutch instead.
Any thoughts would be greatly appreciated, as I'd like to fix the car this week. Thanks!
-Mike
Last edited by ramblux; 08-25-2011 at 05:49 PM.
08-27-2011, 12:49 PM
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2001 C320, 1997 E320, 1993 300e & 2005 F150 Supercrew
Hey ramblux, glad you found your problem.
I just replaced my sons compressor and drier on his E320 a couple weeks ago. I picked up a compressor/drier/expansion valve kit on ebay for $250 with free shipping.
There's an excellent DIY on benzworld.org by jnash. I had no pressure in my system (compressor seal blew) so I didn't have to pump the system out. It only took a couple of hours to replace the parts.
I also bought a vacuum pump and gauges to refill the system (youtube has a great DIY on that). It was good weekend job.
My sons AC system has been working great. Hope this helps out.
Feel free to email me if you have any question
Rusty
I just replaced my sons compressor and drier on his E320 a couple weeks ago. I picked up a compressor/drier/expansion valve kit on ebay for $250 with free shipping.
There's an excellent DIY on benzworld.org by jnash. I had no pressure in my system (compressor seal blew) so I didn't have to pump the system out. It only took a couple of hours to replace the parts.
I also bought a vacuum pump and gauges to refill the system (youtube has a great DIY on that). It was good weekend job.
My sons AC system has been working great. Hope this helps out.
Feel free to email me if you have any question
Rusty
08-28-2011, 02:15 AM
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1999 E320
Hey Rusty,
Thanks for the info! That sounds like a good way to go. Which seller did you get the kit from?
I'll certainly e-mail you once I dig into the car, and thanks for your willingness to help!
Thanks for the info! That sounds like a good way to go. Which seller did you get the kit from?
I'll certainly e-mail you once I dig into the car, and thanks for your willingness to help!
08-28-2011, 04:53 AM
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2001 C320, 1997 E320, 1993 300e & 2005 F150 Supercrew
Ramblux,
No problem, always willing to help a fellow DIY'er.
Search for: New A/C AC Compressor Mercedes A/C AC Compressor Kit $244
The seller is: goldautoparts
Email me and I'll send you more info on how to do it.
Rusty
No problem, always willing to help a fellow DIY'er.
Search for: New A/C AC Compressor Mercedes A/C AC Compressor Kit $244
The seller is: goldautoparts
Email me and I'll send you more info on how to do it.
Rusty
