A/C clutch clicks but...

[Trueno]

...clutch doesn't engage. A/C failed quickly over the past few days, reared its ugly head right after accelerating (3000-3500rpm burst) up an onramp to the freeway. Only a few spurts of AC after that.

Tried to add 134 (there went $23 ) but it's full.

Watched the clutch and can hear it 'click' like it's cycling but no motion at all. Doesn't 'suck to the rear' to close the air gap or anything so I'm assuming she needs a clutch. Plan is to swap without opening the system, preferably with the compressor in place.

Still got a lil bit of youngster left in me so I think it's worth a try, what say the mob?

t

 

[JUST4FUN]

I suggest if the clutch is bad replace the whole thing just my opinion

 

[stamp11127]

Check for power at the plug first. If the low or high pressure switch trips then there isn't power to the compressor. If there is power but the clutch isn't engaging it is obviously worn out. The compressor isn't far behind it also.

What was the low pressure reading and outside temp when you tried to add the refrigerant?

 

[IMINYOURCHAIR]

yeah, for a simple swap, you will just need to have an ac shop evacuate the system of freon (illegal to knowingly release R-134 to the atmosphere) then you have to know how much oil they recovered then recover any extra oil from the old compressor. add that exact amount back in on recharge.

I rented a gauge set for $50 and a vac pump for $150 or $200, I can't remember. you will get the cash back when you return them. you can order some r134 online but stores also sell it but for more $$.

when you evac the system go ahead and pull and inspect the orifice tube for debris or signs of black death. This is mine after 230k (when the PO had the compressor bypassed for the same issue you've had I believe) Here is a comparison from black death and new orifice tubes.

 

[Trueno]

I suggest if the clutch is bad replace the whole thing just my opinion

I trust you would be discreet in using Western Union to wire $800 for parts and tools into my *****ian bank account? If you would be so kind, it would expedite matters greatly.

viva John Wayne!




eta: wow, can't even use the word Ni ge rian

 

[Trueno]

Check for power at the plug first. If the low or high pressure switch trips then there isn't power to the compressor. If there is power but the clutch isn't engaging it is obviously worn out. The compressor isn't far behind it also.

What was the low pressure reading and outside temp when you tried to add the refrigerant?

Temp and gauge both around 85.

I would think there's power to the clutch, it just isn't engaging. Maybe I wasn't clear...it 'clicks' almost as if it were cycling on/off, every 20-30 seconds or so but the front plate doesn't move rearward to the magnet/coil. I usually associate the clicking sound with the plate moving to the rear or when it releases from the magnet. Sheesh, $100 just for the clutch.

Got a guy here in the hood that wants to trade a 2000 Expedition XLT w/5.4 that doesn't run, he's open to trading it for a gun, might take him up on it.


t

 

[stamp11127]

Do you have manual or EATC? If yours is manual I can understand hearing one click but not the cycling. If you have the EATC I'll look into the cycling - dont understand why it would cycle on/off since the pressures aren't tripping the limit switches.
On the otherhand if the clutch is engaging then then low side press is high. Do you have a set of gauges to read the high side?
One thing comes to mind though, if the.clutch uses a keyway it may have sheared off. We have always replaced compressors as a unit - none of the clutches have failed.

 

[Trueno]

Controls are manual.

Starting to recall a few small episodes of it not cooling here and there in the last week. Turned the main selector OFF and waited 10sec, then back on at MAX with low fan speed and I could feel very cold air coming out the vents.

Accelerated on down the street and the air turned warm/ambient (not HOT), slowed down to an idle but it didn't cool again. Rear air followed the same pattern so it's not the blend doors(?)

t

 

[stamp11127]

Trueno, the air gap on the clutch is adjustable, range is .014 - .030" measured in three places. You'll need the clutch holding tool and access to the center bolt in order to make adjustments. Probably with an impact.

Send me your email in a pm...

 

[Trueno]

Trueno, the air gap on the clutch is adjustable,

Starting to second-guess myself now as to whether what I actually heard was the clutch mech or not. If it were, then it stands to reason that the plate would have moved SOME kind of distance.

To add insult to injury...just got back from the junkyard, bought a coil off a 5.4, not sure the year but it doesn't fit my 4.6. The plug is different, 5.4 coil has an internal shoulder that prevents my 4.6 plug from going all the way in. The 5.4 coil also has larger spades versus smaller on the 4.6 version, pretty sure I know where I'll be headed come Monday.

{crying smilie goes here}

 

[stamp11127]

Hey, as long as you're not wandering around the neighborhood lost, all is good.

Sent you an email.

 

[Trueno]

Just dropped my lil convict off at her sister's house, 'legs' is busy doing things for her mother, but my shorty kiss is waitin' on the front steps uptown and I figure I deserve some sort of reward so I'm takin' the rest of the day off (hubba hubba!)

Got your emails, I'll dig into the PDF asap!


t

 

[JUST4FUN]

What if you just burnt out the clutch but you added 134 to the system now its over charged

 

[stamp11127]

I doubt he could add enough without the system running to overcharge.

But, we'll say he was able to overcharge. Now the system's performance has dropped, temp at the condenser has risen which means the temp for the evap has risen also - less cooling. We'll keep going further, most people would then assume it doesn't have enough 134a and add more. The temps increases again. It may be possible to add so much 134a you are now taking the chance of sucking liquid 134a into the compressor. If you're lucky the compressor pop off valve opens and sprays the oil and 134a everywhere. If not, you will be hearing a loud bang - never have seen or heard it happen though.

For more info:
Section 609 Main

Towards the bottom of the page there is a link to a free study guide that explains how a/c systems work. Once you have read and understand how the process works, you will realize how simple it is. Just a state change of the refrigerant from liquid to gas then back to liquid.

 

[Trueno]

Didn't add any 134, just used the gauge.

t

 

[Trueno]

Hey, as long as you're not wandering around the neighborhood lost, all is good.

update..............

Well, I'm lost for sure now. I mentioned the trouble started with the onramp, figured I fouled a plug that was on its way out and the A/C was just a side coincidence.

Codes showed both O2 sensors and #7 (G) COP as culprits.
Swapped #1 COP and sparkplug into #7 hole,
Swapped #7 plug into #2 hole and #7 COP onto #1,
#2 hits (good plug) but #1 dead (bad COP).

Needs a COP. Grabbed one at the junkyard, slightly different connector but a few passes with a Dremel and good to go. Installed it on #1, purrs like a kitten...

...and the A/C works. Gassed on it a few times, still purrs and blowin' cold air. Gonna take her around the block a few times and see. Think something in the PCM shuts down the A/C when there's a dead miss? Maybe a Wide Open Throttle switch got stuck...andthen became unstuck at the exact same moment I just happened to swap a good COP in?

what say the mob?

 

[IMINYOURCHAIR]

it's possible that with multiple emissions codes and a misfire that it cut the ac to lessen the load as a form of a "limp home" mode.

 

[stamp11127]

I haven't been able to find exactly what the pcm does when it goes into what Ford calls: Failure Mode Effects Management or Limp Home Mode.
What I have found says it will light the CEL, throw a code and possibly richen the a/f mixture. If so, I would suspect the cause to be the O2 sensors and not the COP change. But if that is true you now risk taking out the cats from the overly rich mixture if not corrected quickly.

If you were to put the old failed cop back on a different plug and the a/c failed again, that would indicate the pcm does in fact kill it.

It would be great if Ford Customer Service would add to this with exactly what the changes are in the pcm programming for the limp mode.

And thanks to IMINYOURCHAIR for that thought - I had forgotten about the limp home mode.

 

[IMINYOURCHAIR]

if you guys like, I could simulate a mass misfire event. (pull a couple fuel injector connectors) and see if the ac cuts off?

 

[stamp11127]

I did find this after sending a pm to Ford Customer Service about the limp mode. Although it is for the Escape I would assume the logic is similar for other models.

http://www-odi.nhtsa.dot.gov/acms/cs/jaxrs/download/doc/UCM433610/INRL-DP12006-55086P.pdf

Gets interesting around pg12 and beyond concerning the three failure modes and what the pcm does accordingly.