Input on air-conditioning failure before taking to shop?

Viva · 11-03-2015, 10:51 AM

Hi folks,

The (dash) air-conditioning on my 1998 E-350 (V-10) quit working yesterday. I'm not planning to fix this myself (am traveling), and thus will be bringing it into some "un-known to me" shop (see: traveling). As such, I'd like to have some idea of what might be wrong before I go in, just so I might be able to tell whether or not they are on track. I'd be happy to do any tests I can do if there is anything, before-hand.

A bit of history: The AC worked fine when I bought the van about a year and a half ago, and seemed to work fine right up until recently. I think it sort of died slowly, because I was starting to think, gee, this AC is not all that cold, but.... has it really changed or was it always weak? I had measured the air at the vents this summer, and it was in the 50's. Obviously not great, but it was very hot out and I never did do that "Max AC" project yet, so wasn't sure if it was normal (had not measured before). I was just going to see if it would improve after installing the Max AC mod (this keeps the "heated vents" from happening; not sure if or how much that affects AC in our rigs).

Couple days ago, crossing the Mohave, it did seem a bit warm. Then yesterday... okay, there is NO cold air coming out at all. Ambient temp, 84º, air coming out vents when on "normal AC" -- 91º. This puppy is broken! But I guess it died slowly, if that's any help in ruling things in or out.

Anything I can check to get an idea of what is wrong before taking it in? Even when I don't do a repair, I like to be an educated owner. Especially when going to an unfamiliar shop, when I don't totally know whether or not they know what they are doing.

Thanks!
Viva

PS: I tried to search the archives before posting, but "air-conditioning" and "AC" are such well used terms that it was nearly impossible to pinpoint anything in the mountain of available search results.

PPS: No Starcool, rear, or any other AC than factory dash Ford stuff.

mikracer · 11-03-2015, 10:58 AM

I wonder if the Freon leaked out. A shop that can refill your Freon can test to see how much is in the system. If its low or completely out, they can refill it. But of course if its leaking, you would want to repair the leak.

BajaSportsmobile · 11-03-2015, 11:00 AM

First check to see if the compressor is working when the AC is turned on.
If you can see the compressor clutch turning then most likely you're just low on freon.

carringb · 11-03-2015, 11:03 AM

What he said^

50F is much warmer than it should be. probanly have had a slow leak for a while. Eventually the pressure gets low enough it won't even switch on.

Viva · 11-03-2015, 02:06 PM

Okay, I thought about that possibility. In my previous SMB (was a '97) the AC did not work when I bought it, I had the refrigerant topped off (and they found no appreciable leak) and the AC is still working fine four years later (friend owns it now). I guess I'd call that a slow enough leak not to worry about. But that was my previous SMB.

On to this one - a couple of questions that probably sound stupid if you know the answer (I don't).

1) Will the compressor still come on if it's out of refrigerant? (So I mean, if it's out of refrigerant and I don't hear the compressor, is that normal or should it come on either way if the compressor is okay?)

2) What am I looking for to tell if the compressor (or clutch?) is engaging? Where?

And one more bonus question

3) If the refrigerant has run completely out, but the compressor is fine, do they need to do anything to "purify" the system or can it just be filled? I realize any decent shop should know this, but since I don't know any shops, I will need to be evaluating them, and knowing what is right and what is wrong could help me out there.

Thanks! As you can tell, the Air-con system is completely out of my knowledge area.

larrie · 11-03-2015, 05:52 PM

You may be able to hear the compressor clutch engaging when the AC is turned on. Have someone turn on the AC while you are outside the van near the compressor. If you her a click/clunk the compressor is turning on. I believe the compressor should come will try to start with or without freon in the system.

The shop will draw a vacuum on the system to remove all the air before putting the freon back in. Freon is a solvent so no cleaning of the system is needed.

It cost us around $100 for w freon refill a couple of years ago.

carringb · 11-03-2015, 10:46 PM

The system normally uses the low-pressure switch to turn the compressor on and off. Unless it's really hot, it actually doesn't run full time. Because of the that strategy, once you get low enough on freon, the compressor will no longer turn on at all.

Really, it needs to be hooked up to a gauge. If there is still some freon in the system, it's probably fine to refill, but add some dye to help find the leak later. If there's no freon, the leak is probably big enough to allow moisture in, and maybe other contaminants. At this point, the filter/drier will need to be replaced , and possibly the orifice tube for good measure. If the compressor was not making bad noises before (groaning, grinding, or scraping) than it's most likely OK.

Viva · 11-03-2015, 11:50 PM

Thanks for the additional info. Sounds like the compressor may not come on (even if it is fine), if the refrigerant is too low (I had wondered about that), but I'll take a listen anyway. I guess if it does come on, that's something; and if it doesn't, it's inconclusive.

I'll keep in mind about the filter/dryer and orifice tube. I'm not trying to cheap out on fixing it, but rather just that I often seem to hear of people getting AC work done and it gets mucked up, so I want to go in with *some* knowledge of what to expect from a knowledgeable shop.

There were no unusual noises from the compressor that I noticed (and I usually don't have the stereo on, so I would think I would have heard them if they were there). Really the only slightly odd noise I hear in the HVAC system at all (and it has always done this) is a very slight "squeeek" when I turn the HVAC knob to the "Off" position (I guess some blend door is closing or something).

I'll let you all know how I make out. Thanks for the advice (and if anyone has anything further to say, I'm happy to read it).

Viva

Ozrockrat · 11-04-2015, 02:52 PM

Grab a can of freon with the fill adapter and some type of gauge. Put it on and see what the reading says. AC must be turned on. If it reads low give it a squirt and see if it comes up enough to bring the compressor in. The fill per the instructions on the can.

Also check the vac lines to the controller if these are buggered the flap on the heater door or between the floor/demister/face for the vents will not work.

Freon with dye would be preferable but without will be fine. Just something like this would do the job. Watch a couple of YouTube videos and go from there.

Warning. Do not tip the can upside down and give it a big squirt. It will flow a liquid instead of a gas and can cause the compressor to have a fit.

http://www.idealtruevalue.com/store/...FQYIaQodlrMEDw

MadScience · 11-04-2015, 09:11 PM

The compressor clutch is on the very front of the compressor. Mine felll off entirely ~ a year ago. This state was confusing, since while it didn't look quite right, I was under the impression that it was running until I compared it to some pictures. If you still have the clutch, then the front should be spinning when it's engaged.

Here's a picture of a clutch and pulley:

http://images.whisystems.com/smartpages ... -11128.jpg

(yes, that's not a ford one, but it should give you an idea)

When I replaced my clutch, I found that it was short cycling, and had a shop top off the charge. It's been working fine since then.