Air Conditioning Problems

08/01/2007, updated 09/18/2009

Updated 09/18/2009

My AC is not running. The clutch wouldn't even try to
engage. This is a less than one year old new compressor
and clutch assembly that ran fine from June to Oct last
year. This is not the 'bad clutch' symptom - I
seems that no power is getting to the clutch. I have read
everything on the site about AC, but could not find anything
covering my problem. Are there any fuses? Cut out
switches? Any help would be much appreciated.
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In the front right corner, on top of the receiver and about 3" from coolant overflow tank front bracket is the AC low suction pressure switch. It is positioned vertically. Remove the plug and jumper the two wires with the car running and the AC system turned on. If the clutch engages than you are low on refrigerant.
Lucien

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A couple of weeks ago my AC took a dump on account of the clutch being
out of adjustment.
I have not tackled the repair because I have not made the suggested
tools and have not had the time.
Well, now it is making a horrendous noise.
I turned on the defog Monday morning (which uses AC intermittently)
and all of a sudden after heading down the road to work a horrible
noise issued out of the engine compartment, "GRAAAAAGGGHHHHH!... Kind
of a similar sound to a bearing wobbling on a shaft or a bad bearing
and somewhat similar to the sound a bad heater blower makes. It will
not do it at idle and does not do it when on vent or if the
temperature is set higher than cabin temperature.

Could it be the clutch failing?
Maybe the compressor is frozen and the clutch is slipping?

Any advice?

Lee Smith
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I would be concerned it is a compressor itself since the clutch bearing is still spinning when the AC is off.

Carter Fuji
Latitude 35.23948924537855, Longitude -94.30673988764765
'97 ES Whoosh CarDomain Site
Supercharger Video Link
Greenwood, AR.
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Interesting that I am having an AC issue myself that I really don't understand.
The last 100 miles on the way back from K-zoo the compressor started cycling on-off every 10 seconds. It was still blowing cold but the constant cycling was getting me concerned I would have to replace the compressor or clutch since it would probably accelerate its wear. I figured it was low on freon so I picked up a big can with the gauge mounted on it. When I connected the line it indicated "HIGH" by about 10 psi (60 - 65). When I got home I found an old can from a different manufacture and tried it but it was off the scale. I used this can before Indy and haven't touched it since.
Harbor Freight just happen to have a sale on this week for an AC Manifold gauge set at $39 I figured it would be a lot cheaper then the shop to tell me what was really going on. Much to my surprise it also read high but up around 100. Now I am not real sure why but while it was at fast idle the compressor was staying engaged and not cycling while it was about 97* here at 82% humidity. I didn't drive around in it since I was dripping in sweat and didn't want to leave that all behind in the car.

Carter Fuji
Latitude 35.23948924537855, Longitude -94.30673988764765
'97 ES Whoosh CarDomain Site
Supercharger Video Link
Greenwood, AR.
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Lee - I second Carter's thought. I'd be looking towards compressor internals.
Try to turn the center of the clutch with the engine off. Does it feel
gravelly or smooth?
Could also be a clutch that is right on the break point with
clearance, so it half heartedly grabs but keeps disengaging and
grinding. Pulling the "Shim" may alleviate this, may not.

Carter - Shot in the dark - Maybe you should try letting some out. You
may have been cycling on a HIGH pressure switch, especially at higher
RPM's. Water vapor freezing in your capillary tube can do this kind of
thing too. Were you vacuumed out properly before charging?

Eric Lehmann
97 Ebony 42k Welded - With the Angels Now so that I don't have to be.
Long Live the Garage Queen !
96 Medium Willow Green Metallic 103k Resurrected, Welded, Eaton M90 inside
96 Rosemist 72k 2006 Best Of SHO, Popular Vote, 2007 Best Gen 3, Welded
96 Medium Graphite 120k - Resurrected, Welded
97 Pacific Green - Parting this one Out
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Yup (vacuumed out before re-charging). Sorry about not being up on the e-mails, but been a little pre-occupied.
Took it to a shop today since I haven't had time to look into it deeper myself but they couldn't figure it out since it worked fine for them as they check it on MAX. When it is on the normal settings it cycles but they didn't confirm that near as I could understand. They did say that the pressures all looked good to them but it was cycling on the way there this morning so I don't understand. 3 different gauges I used showed it was to high. I might get some time to check it again tonight

Carter Fuji
Latitude 35.23948924537855, Longitude -94.30673988764765
'97 ES Whoosh CarDomain Site
Supercharger Video Link
Greenwood, AR.
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Helms says you check it at 1500 rpm. At 90 degrees or above it should not cycle at all. High pressures should be somewhere from 150 to 260 psi.

bjshov
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I have a AC related question, I had a Line burst on me today, and I wondered
if the lines from a SLO are the same. I found a line on ebay that is for a
SLO and wondered if it would fit.
Charles Ridinger
Cam Failure # 824 Back in business
Piece of mind achieved @ 190022
1997 ES, HID's, LED's 1999 light conversion
Clear corners, Lowered, Flomaster 40's
Removed 3rd cat, 4" Mandrel Bent CAI
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Okay, I got some numbers this evening. At about 2,000 - 2,500 RPM the low pressure side drops to about 40 psi and then the compressor turns off the pressure climbs to about 80 then the clutch engages again but within about 10 seconds it is back down to 40 and shutting down again. High side runs 325 then runs up to about 400 before shutting off.
Carter Fuji
Latitude 35.23948924537855, Longitude -94.30673988764765
'97 ES Whoosh CarDomain Site
Supercharger Video Link
Greenwood, AR.
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You got some crap in there. It is causing flow problems before the evaporator.
The combination of low pressure cutout and very high discharge
pressures indicates a blocked orifice somewhere.

I HATE it when my orifices get blocked.

Eric Lehmann
97 Ebony 42k Welded - With the Angels Now so that I don't have to be.
Long Live the Garage Queen !
96 Medium Willow Green Metallic 103k Resurrected, Welded, Eaton M90 inside
96 Rosemist 72k 2006 Best Of SHO, Popular Vote, 2007 Best Gen 3, Welded
96 Medium Graphite 120k - Resurrected, Welded
97 Pacific Green - Parting this one Out
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And replacing that line is very difficult
bjshov
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Uh, yeah. Blocked orifices pretty much aren't fun. Spent an half an hour on the phone with Lucien last night as he explained what had to be done to give it an enema if I was to try to save it. Doesn't sound like fun since it connects behind the alternator on one end.

Carter Fuji
Latitude 35.23948924537855, Longitude -94.30673988764765
'97 ES Whoosh CarDomain Site
Supercharger Video Link
Greenwood, AR.
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The problem is not the blockage, but rather where the material came from that's doing the blocking.

Don't forget, there is an orifice tube inside the liquid line. Don't let anyone tell you that you have to replace the line. There is a union in the line under and behind the coolant reservoir. Inside this union is the orifice tube. It's the difference between a $6 tube and a $130 line.

Here's the thing. R-134a is tricky stuff. it'll mislead you in a second when looking at a set of gauges. The first thing I'd do is get a new pressure cycling switch and drain the system. Then I'd pull the orifice tube out and see what's on it. The tube is a filter in the system and will trap any crap floating around. If it's clean (relatively), it'll tell you that the system is OK, it was just contaminated with moisture or air (non-condensable). With the system sealed, put a long hard vacuum on it and fill it with the exact amount of freon required. Any air or moisture in the system and the pressures get screwy. Over or under charging by as little as 4oz and the pressures get screwy. By pulling a hard vacuum (30inches for 30-40min), any air or moisture in the system will be removed.

Doug Lewis
Ford Performance Specialists Inc.
Atlanta Georgia (770) 949-7191
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To the best of my knowledge none of the hoses cross on the parts lists.

Carter Fuji
Latitude 35.23948924537855, Longitude -94.30673988764765
'97 ES Whoosh CarDomain Site
Supercharger Video Link
Greenwood, AR.
_____________________________________________________________________________
My compressor exploded last summer, so I replaced the compressor and the hose with the dryer in it. Then my dad reminded me to change the orifice. But I could not get the orifice out of the hose. First with the hose in the car there is very little access to it. Secondly for some reason the fittings at the orifice tend to corrode badly, and my car has been in Texas most of its life. I couldn't get the orifice out so I tried it with the old one in. Pressures would not work at all with that setup so we ended up ordering the whole line that contains the orifice. After I took the old line off I still couldn't get the orifice out, using all manner of normal semi-destructive tools. I had to use a hacksaw to get the old orifice out and find that it had a few little chunks in it.

As for the lines themselves, they both follow the face of the inner fender right at the end of the engine, then connect low on the firewall. There is very little room to work with the engine in there, but it can be done. The hardest part was disconnecting the connections at the firewall. I squirmed around for a long time and could not find a vantage point to even SEE one of them. From underneath you cannot get a hand in there. From the top you can reach them if you have real long arms. I finally discovered there was a little better access from inside the fender. Swapping the lines would only be a 5 minute job with the engine out!

As for the old compressor- we were about 70mph on a divided highway when it went, and I felt it go but just barely. When I pulled it out, the case had split open, with about a 1/4" gap down one side.

bjshov
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I took it to a shop that specializes in automotive AC this morning. They make custom units for street rods and their lot was packed this morning. Waiting for a call on what the damages will be before they work on it. Expecting around $250 but I hope I am pleasantly surprised by a lower estimate.

Carter Fuji
Latitude 35.23948924537855, Longitude -94.30673988764765
'97 ES Whoosh CarDomain Site
Supercharger Video Link
Greenwood, AR.
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What a timely topic. The 96MG's compressor went to Jesus about two weeks ago. Now in Milwaukee it's mid 90's with dew points off the map. SW9, which has it's own issues was my A/C fall back - until the Crank position sensor went to visit the same wise man. Pfish is awaiting my benji's for a new compressor for the 96. Meanwhile I drive 130 miles round trip a day in my own juices. The old time joke about "Polish A/C ain't funny anymore!!

U.L.
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Doug, thanks for this information. Even though the service manual states that orifice is color coded orange, this seems to be useless information because the manual also states that if replacement is necessary either replace the condenser to evaporator tube or install an orifice tube replacement kit. I checked both the '96 SHO I'm currently working on and my daughter's '96 LX with 3.0 Duratec and found the compression fitting in the same location on both. Doug, what has been your experience for the most common extraction method for the orifice i.e. fingers, needle nose pliers, scribe, etc. Thanks again,

Lucien

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