96 E320 AC issues, at my wits end.....

[vanzack]

I have a 96 E320 that is blowing warm/hot air from the drivers side vents, and blowing ice cold from the passenger side vents.

I have searched and read every post here about it and have already preformed the following tasks:

1. I did the diagnostics on the AC through the onboard computer (by way of the AC display). Everything was fine.

2. I did the error check through the onboard computer and there were no errors (by way of the AC display).

3. Recharged the freon to the maximum capacity. There is no hissing noise behind the vents to indicate low freon. (dont know if freon is the right word - but had this step done professionally so I dont know what to call it).

4. I opened up the Duovalve and cleaned it and put it back together. It looked to be in pristine condition when I opened it but lubed it up anyway.

5. I discovered the flap test outlined at continental imports site and ran through it and I think it failed all over the place.

Just fyi - these are my diagnostic values:

1. 41
2. 40
3. 24
4. 25
5. 25
6. 88
7. 13
8. 52

I see in a lot of places how to test and evaluate the flaps - but nowhere how to fix them. I failed lots of the flap tests, including left and right diverter flaps and left and right blend flaps. Any leads on repairs to flaps?

Still no good results. The problem is intermittent which drives me further insane. When it is hot outside, and when I am driving at 30MPH+ it is the worst. When I am idling it seems to work better, but at its best it is still at least 5 degrees warmer on the drivers vents than passenger vents. At its worst, the drivers blows HOT and the passenger is COLD.

Could the problem be with the vacuum or the vacuum switchover block?

I live in Florida and dont care if I never have heat available to me so if there is a solution that would involve me locking something open to only allow cold air that is fine with me.

ANY SUGGESIONS?

I APPRECIATE ANY HELP OR SUGGESTIONS - I AM GOING CRAZY WITH THIS!!!

[mbdoc]

That reading for number 7 is the problem!!!!

13 is = to 13bar times 15 = pressure in psi on the high side..

195psi is WAY too low of a high side reading....are you sure of the re-charge??? if not then the expansion valve OR the compressor is most likely at fault..

Is the drier cool OR hot with the system running.?...should be VERY hot.

[vanzack]

Originally Posted by M.B.DOC

That reading for number 7 is the problem!!!!

13 is = to 13bar times 15 = pressure in psi on the high side..

195psi is WAY too low of a high side reading....are you sure of the re-charge??? if not then the expansion valve OR the compressor is most likely at fault..

Is the drier cool OR hot with the system running.?...should be VERY hot.

Thanks for the response.

I had the recharge done at a shop and they used dyed recharge. Could it be a leak somewhere? They said the compressor is still good.

I dont know what a "drier" is - can you explain so that I can tell if it is hot or cool?

Are you also ruling out the possibility of the flaps not working right?

Thanks again for the help.

[vanzack]

Any ideas out there?

I am about to take it to the dreaded dealer to be overcharged for them twisting a bolt 2 revolutions.

Please help!!

[Gilly]

"Drier" is the receiver-drier. Under the hood, follow the small hose that come out of the condenser, it will go to a small (a little smaller than a coffee can) tank with a window on the top (round peephole type window, where you look to see if you are low on freon), THAT's the receiver drier.
Gilly

[vanzack]

Thank you very much Gilly - I will check it out.

[Gilly]

NP Vanzack. I've seen this before too re. low on freon=only cool air on one side, I think this is probably it, assuming Doc is correct on those readings, more than likely is spot-on as usual. It's a sl-plit system and if you're low, there is only enough to start cooling one side of the evaporator, the other side gets "jack" cooling effect.
Gilly

[brewtoo]

Originally Posted by Gilly

"Drier" is the receiver-drier. Under the hood, follow the small hose that come out of the condenser, it will go to a small (a little smaller than a coffee can) tank with a window on the top (round peephole type window, where you look to see if you are low on freon), THAT's the receiver drier.
Gilly

And while you're feeling the drier to see if it is hot, peer into that little window on the top and see if you see a lot of bubbles flowing by. If so, your refrigerant level is probably low.

[vanzack]

I cant thank you guys enough. I will check it.

If it is low - then I either got ripped off by the shop when they said they filled it or I have a leak.

My question - are you guys eliminating the flaps as being a potential culprit here?

[brewtoo]

Strange as it sounds, it is possible to have cold air from only some of the vents if the charge is low. Verify the performance of the cooling system before you worry about the flaps.

[Matt L]

As this is a '96, there is no sight glass in the receiver/dryer. It's located behind the left headlamp, in front of the washer fluid reservoir.

I'm not sure that 13 is too low for the high-side pressure. Mine runs about that at 100F out when idling. But if it were mine (and I've had this problem as well), I'd add a few ounces and see what happens.

If the refridgerant charge is correct, you may need a new receiver/dryer. Some of the older ones get restricted, causing this problem (according to WIS).

[Southern]

From the looks of the diagnostic values they appear to be before the engine was at operating temp. From my recent experince with low freon I noticed that with the engine at operating temperature and the AC running for at least 15 minutes, the left heater core temp (3) will be higher then the right heater core temp (4). You will also notice a greater difference between the inside car temp (1) and the outside temp (2).

Since the W210 uses a variable compressor, you will need to monitor the refrigerent pressure (5) instead of looking at a snap-shot. Now that my W210 blows cold air on both sides, I noticed that the refrigerent pressure runs around 15 bar.

When I ran the flapper valve test, I noticed that there was about a 5 second delay for the valves to reposition.

I also think that your car is low on freon.

[vanzack]

Just an update:

I took my car to the dealer today, had both guages put on to test the pressure - one on the high pressure and one on the low. The pressure was showing between 16-19 bar.

There are no leaks and my pressure is good, and the freon level is absolutely full.

So now I am really at my wits end.

1. Duovalve works fine.
2. Full refrigerant with no leaks.
3. Compressor, drier, evaporator all working fine.

Only thing left are the flaps. And that seems exhaustive to diagnose and/or repair.

I dont know how to go forward and I dont really expect anyone to give me any golden advice - I just wonder if anyone has ever worked on the flaps and if so what am I up against? And could this problem even be the flaps? Or something else?

THANKS

[foxden]

The heat on the drivers side and cold on the passenger was the tell tale sign to lube up my duovalve unit. One time I had to do it twice even though it appeared fine.

You can clamp off one of the hot water lines to the valve which will prevent hot water flow and see if this corrects the issue. The valve might be fine but not getting a signal to close properly.

Its simple to try and definitely would isolate that issue.

[stevebfl]

It would seem unlikely, but when the 210 cooling variance problems first came out ten years ago or so, it was noted that any refrigerant performance problem would show in this fashion, cool on the right, warm on the left. One issue that I'm not sure I ever saw was a reported problem with the storage capacity of the receiver-drier. It is a chamber for accumulating liquid refrigerant and if the effective volume is reduced it affects performance.

The possibility of a heater issue should be easy to eliminate. The actual values for the two heater core temps would be the first place to look.

The actual value #5 is evap temp and 25deg C is almost no AC. You should get down to close to "0" atleast below 10. I expect 4-5deg C usually at 50mph. If you are still only getting 25 you have a serious refrigeration issue. What is the low side pressure, that is what matters for diagnostics. At 25 deg evap, low side is probably 70psi or more.