zdzich

Hi. A few weeks ago I had a problem with my AC. I charged it up with a can of R134 and was fine until last Friday. I lost my AC which is no good at this time of the year in Las Vegas. I checked the pressure by connecting my pressure gauges. Engine idling, temperature on both sides set to Lo, fan at full blast, outside temp this morning was 77. Low pressure side 35 psi, high pressure side 195 psi. Air at passenger side vent cold, driver side not so cold and getting warmer. After a few minutes both vents have warm air and getting hot. At that time pressure on low side jumped to 110 and pressure on high side dropped down to about the same. I took apart the duo valve but it was clean inside and both pistons and O rings in good condition. Voltage on both solenoids was the same, 13V. This means both valves are closed, no hot water going to the heaters. I went through the AC diagnostic and this is what I got on the AC control unit display:
1 - 91
2 - 78
3 - 87
4 - 80
5 - 138
6 - 186
7 - 14
8 - 139
10 - 6
11 - 3
12 - 3.3
20 - 7.8
21 - 42
22 - 00
23 - 32
24 - 13.1
40 - 164
41 - 32

Would anyone tell me what is going on with my AC system ? I suspect a bad expansion valve. Thank you.

Plutoe

I will assume that you know what all the numbers mean, however what is missing are the faults if any---have you done that step??

In any event if Mr bla bla bla was here he would no doubt suggest a private message to sell you something. I wont bore you with wasting money on needles parts.

First you wasted you time taking apart a good duo valve. The duo valve is apart of the heating system and has nothing to do with the AC high pressure-evap-low pressure loop. Forget the duo valve and move on.

The important stuff is 5,7,8-------5 is the evap temp sensor showing 138 when an acceptable number should be in the low 40's.

7 is refrig pressure in bar---you are showing 14 a good number is 17

8 refrig temp sensor is showing 139. If you have a chart you will note that is equal to approx 232 psig and 16 bar.

At first one could possibly come to your conclusion, but I don't think so ---not yet

Do the fault test and first see what sensors may be bad if any----when you have that info you can then come to a conclusion, but not before.

zdzich

Thanks Plutoe for your feedback. Sorry that I forgot to mention that there were no fault codes. I checked twice the number on step 5 and was around 138. So, I decided to order a new expansion valve and a new receiver dryer. It is a 13 year old car and these are mechanical components that should be replaced anyway. As far as I know there is no fault codes for a bad expansion valve. What do you think ?

Plutoe

I agree with you there is no direct expansion valve fault. If you are sure the compressor makes pressure and the evap sensor is good, yet the evap temp is way high, I would also agree with you.Good Luck!!

zdzich

Finally, I got my AC working. Replaced the expansion valve, receiver dryer, and evaporator temperature sensor. Vacuumed the system and filled it with fresh refrigerant and oil. Works great in this Nevada hot summer.

georgiabenz

I just replaced the ac compressor on my 2000 E320 with one that I had previously taken off a car my wife totaled. The replacement compressor was less than a year old and had been stored properly for 18 months. I also installed a new receiver dryer along with it. After installing the comp and r/d I pulled a vacuum on the system and let it sit for two hours with no bleed down or leaks. I recharged per spec and reset the ac fault codes, the ac worked perfectly with ice cold air for three weeks. Today I jumped in and took off but the ac didn't blow cold, only outside temp air. Yesterday it worked fine.

Here are the numbers:

The EC light is NOT on.
The AC Clutch will not engage.
The Low Pressure reading while running with ac on is 110 psi.
The High Pressure reading while running with ac on is 150 psi.
The only fault code is E 1419.

Here are the readings with car running in 84 degree heat:
1 100
2 84
3 107
4 107
5 103
6 181
7 07
8 91
9 30
10 4.5
11 2.8
12 4.2

Does anyone have an idea where to start troubleshooting?

fabbrisd1

If you want to get evap sensor out of the way for $14... the China part is A-OK .. and there should be a sticky - takes 10 minutes inside the cabin...

nikono

When AC is on, engine at idle for few minutes, fan at max, sensor#7 should read 15. If 0, it means big leak, all refrigerant's gone.
That happened to my car twice with sensor#7 reading less than 10 at idle. The first time was some years ago. The second time was just last week in Sacramento. The city was hot at 100-degree F. I remember my car's AC quit being cold when I changed the fan to max at a drive-thru for food. Anyway, I bought the large 22oz regfrigerant can with a gauge at O'reilly, charged. AC cold again until now after being back in LA.
With sensor#7 reading 7 in your case, it's worth a try to add some refrigerant with leak sealer with a gauge to confirm proper pressure. Run engine, set the climate control to sensor#7 to monitor it. Charge at max fan, lowest temp setting on climate control.
AC should be cold when the outside gauge is coming to read at/near upper green zone, at the same time sensor#7 should read ~15 or 16. Continue to run engine for 7-10 minutes to really circulate the sealer in the system.
Good luck.