A/C Checklist

[amsugg]

Hi:

I am new to this forum. Thank you all for your contributions. I recently purchased a 1994 E320 wagon with 147K. I swear I thought I checked whether the A/C blew cool when I test drove it, however today, as it approached 75° outside in NC, I discovered I don't have cool air. This vehicle has been well maintained. I had a long conversation with the garage in Greensboro NC prior to purchasing it. This particular garage had worked on the vehicle for the past 3 years or so. My question is this: Is it likely that since the vehilcle has been so well maintained, and the fact that its got 147K and 13 years old, that the evaporator issue has already surfaced? The harness has been replaced, and the head rebuilt, I am certain. Whether the evaporator has been replaced or not, I'd like to identify what the easy checks would be....The air doesn't blow cold, and the compressor doesn't seem to kick on. Would I start with something like the relay, or a fuse, and next get to the charge leak/level? Can someone just offer a suggestion or two? I just don't want to get "had" since I haven't cultivated a relationship with someone in Durham NC to do work on this vehicle.

Thank you in advance for your assistance.

Andrew Sugg

[fj bertrand]

did you pull a vacuum with it? Go thru the basic a/c check list, THEN ask for an opinion. You haven't given us enough info. good luck

[amsugg]

I've not done anything to to test the A/C. I don't have those skill sets (nor equipment) I just want to be somewhat familiar with what could be wrong so I can at least ask intelligent questions to the mechanic. If there are any other common, simple things it could be? I suppose you are suggesting that the standard checklist is exactly what any A/C mechanic would start with? Again, if anyone has any specific suggestions, please let me know.

Thank you again.

Andrew Sugg

[brewtoo]

Originally Posted by amsugg

My question is this: Is it likely that since the vehilcle has been so well maintained, and the fact that its got 147K and 13 years old, that the evaporator issue has already surfaced?

I certainly would not make that assumption.

How the car was maintained would have no bearing on whether the evaporator has leaked by now.

But, there are plenty of other things that could leak. And that's assuming you even have a leak.

If it was me and I had no equipment, I would probably check to see if there is a low-pressure switch on the top of the drier (a switch with no pigtails). If there is, I would briefly short the leads and see if the compressor comes on.

[amsugg]

I am happy to report that my A/C problem was not the dreaded evaporator problem. According to my newly found (and seemingly trustworthy) mechanic, they evacuated the system due to abnormal pressure readings, and recharged the system properly. As a result, the inside air reached 44°. The only issue we determined was that that one of the dual condensor fans did not engage. We presumed they are both to come on at the same time. The high pressure reading became particularly high, presumably because that 2nd fan was not operating. Can anyone tell me if this sounds correct? Also, can only one fan motor be replaced, or does one have to purchase the entire assembly and two fan units?

Thank you,

Andrew Sugg
Durham NC
1994 E320 Wagon

[brewtoo]

Both fans should run in unison.

[lee polowczuk]

if the other fan wasn't working.... the high pressure probably forced the compressor to shut down...

i just had this issue in my single fan system.... the a/c worked fine until the temps rose... the fan didn't come on... so the compressor shut down..

my fan was just stuck and blew a fuse...

could be a completely different issue...but it shows you there are a lot of ways that the a/c won't work besides the dreaded evaporator issue.

[amsugg]

I did some reading on the forum and tried something someone suggested. As my "driver" cooling fan was working fine, and my "passenger" one wasn't, I decided to spin the fan blade with my hand. As a result, the passenger fan engaged. The fans worked in unison and then continued to turn on and off in unision for a few minutes as the system cycled. My mechanic thinks its a failing fan. Perhaps it is, but could it also be a poor/corroded connection? I hate to spend $200 for a single fan (is the quote he gave) and 3 hours worth of labor for something that may or may not be the issue. Would some type of WD40 lubricant on the connection or inside the motor housing have any redeeming effect? My mechanic has ordered the part, and I'd like to forego my Thursday appointment if I think I'm okay. I know, I know, in an ideal world...get it replaced. However I'd prefer not to spend $400 or so for something I can do without for the time being.

Thank you for your input.

Andrew Sugg
Durham NC

[lee polowczuk]

i sprayed mine with wd40.... after being stuck, it now works fine..

this is on the 260e with 208k

[softconsult]

The fan itself is around $125 or so on-line. Replacement is very basic, but requires some patience as some of the little nuts and bolts are hard to get at. Also the plastic anchors that retain the plastic shroud will be old and brittle and need to be replaced with new ones. I've had two different fans fail on two different 300E's.

Given the temperatures that can be reached in North Carolina, I don't think it is smart to try and get by with one flaky auxilliary fan.

Steve

[brewtoo]

Originally Posted by amsugg

Would some type of WD40 lubricant on the connection or inside the motor housing have any redeeming effect?

My blower motor had failed on my '90 124 about seven years ago. I removed it to replace it with a new one. I chickened out trying to get the squirrel cages off, as my new one did not have the cages and I needed to move the old ones to it. I was certain I would break them.

Well, the motor would barely turn by hand - it was very tight. I put a few drops of motor oil on the shaft and worked it in by twisting the shaft by hand.

I reinstalled the old blower motor and it has worked fine for the last seven years.

YMMV!