A/C issue

jme2712

Original poster
Member
Apr 30, 2013
29
I posted this over at tv before I had realised I wasn't going to get a response.

I've browsed these forums and haven't found any resolutions to my issue regarding A/C. I've had my system checked for leaks and filled, but my issue persists. When I attempt to use my A/C it is intermittent. When I am idle and there isn't a load on the engine my compressor appears to stay engaged, but when I am on the gas I can feel the compressor kick off (more power from engine) I can also feel this going down the highway. As far as the blower it moves the air fine, but I can feel the are go ice cold when the compressor is engaged, but get cool to warm when it disengages. I've spent so much money on trying to diagnose the issue, but haven't been able to solve it. I have replaced the low pressure switch, but that didn't fix it. Any ideas?
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
If the high and low pressures check out, the typical failure is a marginal magnetic clutch operation caused by an excessive gap. Search for those words. If that's too detailed a repair, just get the compressor replaced and the system recharged.
 

triz

Member
Apr 22, 2013
746
Your AC Clutch is on its way out. Have it repaired or replace the compressor before it seizes up and snaps the belt and leaves you on the side of the road.
 

jme2712

Original poster
Member
Apr 30, 2013
29
I do believe that I have the original compressor and the engine has 170k on it. Should I just buy a new compressor or will a clutch do? I've already replaced the lp switch
 

Denali n DOO

Member
May 22, 2012
5,596
Of course, now that I've fixed something, something else goes wrong :hissyfit: So my a/c is acting like yours, sometimes it works and sometimes it doesn't. So the compressor and clutch is this all one unit that I should have replaced or can this magnetic gap deal be repaired I searched those words and didn't find much on repairing. Can you let me know your outcome on how you solved your issue? Thanks.
 

jme2712

Original poster
Member
Apr 30, 2013
29
Denali n DOO;136021 said:
Of course, now that I've fixed something, something else goes wrong :hissyfit: So my a/c is acting like yours, sometimes it works and sometimes it doesn't. So the compressor and clutch is this all one unit that I should have replaced or can this magnetic gap deal be repaired I searched those words and didn't find much on repairing. Can you let me know your outcome on how you solved your issue? Thanks.

Google envoy ac excessive gap. I've yet to dig into this as I need a multitude of things new shocks/struts, airbags and wheel hubs. I'm just not sure what to tackle first.
 

meerschm

Member
Aug 26, 2012
1,079
The AC compressor has an electric clutch. the pulley rotates all the time, and when there is a need for cooling, a signal to a relay sends power to the clutch coil, which pulls the clutch part which is connected to the compressor. when activated, the pulley then provides movement for the compressor, which compresses the R134a, and pulls from the low side.

there are quite a few details, fluid dynamics, highly dependent on temperature and humidity. there are dryers, expansion valves, filters and screens. there is a high pressure sensor which can cut out, and the low pressure switch which can act up. the control is handled by the computers scattered around. the computers can decide not to operate the AC if other things are going on, like if the engine or transmission are overheating (or if it thinks it is) (Roadie may have more specific details)

to replace the compressor, you have to open up the refrigerant circuit. since the R134a is a potent greenhouse gas, and the older R12 was indirectly eating the ozone layer (the good one that blocks nasty parts of the solar radiation, not the bad lower layer kind that makes smog) you are expected to recover the refrigerant for reuse or recycling.

the R134a recovery is not a once in a while DIY.

the compressor comes with a clutch, and if you want to just get the clutch, you can do so. I searched on E-bay, and found a rebuilder willing to post a listing for a rebuilt clutch kit. coil, bearing, clutch, pulley, and shims (the clearance has to be just right. not too much, not too little.) you may be able to pull off the clutch plate, and remove one or two shims. the coil can have intermittent opens, or high resistance which makes it weak. the clutch can wear a bit over many years of on and off. which can misadjust. there also can be little bits blocking parts of the circuit, or the compressor can just wear out, jam up, and throw stuff through the pipes.

first step is to figure out what exactly is going on. for the AC Compressor clutch to be the problem, you want to verify that the signal is to the coil, but the coil is not engaging. (some folks have set up conditions for the ac and gave the clutch a gentle help with a broom handle or such, being careful not to get caught in the other moving parts)

my AC crapped out, but only when it is hot (over 95f. first happened last summer when it was over 100, and when stuck in traffic) I also had a slow leak. I put R134a with some stop leak, and have set up some software to watch the request for AC, AC relay signal, and the high pressure reading. also coolant and trans temperatures. my plan is to verify that it is the clutch crapping out, and when/if it does, try to change the clutch. I have heard you can get the clutch off without pulling the compressor off, and perhaps without pulling the fan clutch and fan blade (for clearance)


I ended at E-bay:

I searched for air parts inc.

And sent a message from inside E-Bay to airpartsinc. And told them what I wanted, (for car model, year and so on.)

They sent back a link to an e-bay post, which included shipping.

eBay My World - airpartsinc

and click on contact member ( you will need an e-bay account.)


if you do not have e-bay account, you could also call:
AIR PARTS INC. 1133 N. Magnolia Ave Ocala, Florida 34475 Toll Free # 800-223-7167

there are places on line which will sell you the various parts. with a compressor you may want to change the dryer and expansion valve. some compressors require a flush be performed for warranty. if you get it open and replace parts, you at least have to pull a vacuum to remove air and more important water. the right amount of oil has to be in, as well as the proper amount of R134a.

the AC is a great thing when it works, when it goes a little bad, it can drive you nuts.

my brother said he spent $800 a year on AC for his old Astro, every year a different thing like four years in a row. (his case included labor since he was not DIY'ing any of it)

Plenty of U tube to keep you busy figuring it out.
 

Denali n DOO

Member
May 22, 2012
5,596
So it seems my a/c works when engine is cold but has a hard time to engage when it's hot, Does this comment I just googled make sense;

"Take the clutch driver off and remove the thickest shim (if more than one) and re-install driver and be done-- I've done several this way."

Is this a way to solve the excessive air gap? I'll have to look at service manual to see if I even have these shim pieces...
 

Denali n DOO

Member
May 22, 2012
5,596
meerschm said:
The AC compressor has an electric clutch. the pulley rotates all the time, and when there is a need for cooling, a signal to a relay sends power to the clutch coil, which pulls the clutch part which is connected to the compressor. when activated, the pulley then provides movement for the compressor, which compresses the R134a, and pulls from the low side.

there are quite a few details, fluid dynamics, highly dependent on temperature and humidity. there are dryers, expansion valves, filters and screens. there is a high pressure sensor which can cut out, and the low pressure switch which can act up. the control is handled by the computers scattered around. the computers can decide not to operate the AC if other things are going on, like if the engine or transmission are overheating (or if it thinks it is) (Roadie may have more specific details)

to replace the compressor, you have to open up the refrigerant circuit. since the R134a is a potent greenhouse gas, and the older R12 was indirectly eating the ozone layer (the good one that blocks nasty parts of the solar radiation, not the bad lower layer kind that makes smog) you are expected to recover the refrigerant for reuse or recycling.

the R134a recovery is not a once in a while DIY.

the compressor comes with a clutch, and if you want to just get the clutch, you can do so. I searched on E-bay, and found a rebuilder willing to post a listing for a rebuilt clutch kit. coil, bearing, clutch, pulley, and shims (the clearance has to be just right. not too much, not too little.) you may be able to pull off the clutch plate, and remove one or two shims. the coil can have intermittent opens, or high resistance which makes it weak. the clutch can wear a bit over many years of on and off. which can misadjust. there also can be little bits blocking parts of the circuit, or the compressor can just wear out, jam up, and throw stuff through the pipes.

first step is to figure out what exactly is going on. for the AC Compressor clutch to be the problem, you want to verify that the signal is to the coil, but the coil is not engaging. (some folks have set up conditions for the ac and gave the clutch a gentle help with a broom handle or such, being careful not to get caught in the other moving parts)

my AC crapped out, but only when it is hot (over 95f. first happened last summer when it was over 100, and when stuck in traffic) I also had a slow leak. I put R134a with some stop leak, and have set up some software to watch the request for AC, AC relay signal, and the high pressure reading. also coolant and trans temperatures. my plan is to verify that it is the clutch crapping out, and when/if it does, try to change the clutch. I have heard you can get the clutch off without pulling the compressor off, and perhaps without pulling the fan clutch and fan blade (for clearance)


I ended at E-bay:

I searched for air parts inc.

And sent a message from inside E-Bay to airpartsinc. And told them what I wanted, (for car model, year and so on.)

They sent back a link to an e-bay post, which included shipping.

eBay My World - airpartsinc

and click on contact member ( you will need an e-bay account.)


if you do not have e-bay account, you could also call:
AIR PARTS INC. 1133 N. Magnolia Ave Ocala, Florida 34475 Toll Free # 800-223-7167

there are places on line which will sell you the various parts. with a compressor you may want to change the dryer and expansion valve. some compressors require a flush be performed for warranty. if you get it open and replace parts, you at least have to pull a vacuum to remove air and more important water. the right amount of oil has to be in, as well as the proper amount of R134a.

the AC is a great thing when it works, when it goes a little bad, it can drive you nuts.

my brother said he spent $800 a year on AC for his old Astro, every year a different thing like four years in a row. (his case included labor since he was not DIY'ing any of it)

Plenty of U tube to keep you busy figuring it out.

Thanks for the good info, guess I was googling when you were replying....
 

jme2712

Original poster
Member
Apr 30, 2013
29
To top this whole situation off my central air has a leak also. Talk about getting it from both ends.
 

meerschm

Member
Aug 26, 2012
1,079
Denali n DOO said:
So it seems my a/c works when engine is cold but has a hard time to engage when it's hot, Does this comment I just googled make sense;

"Take the clutch driver off and remove the thickest shim (if more than one) and re-install driver and be done-- I've done several this way."

Is this a way to solve the excessive air gap? I'll have to look at service manual to see if I even have these shim pieces...

The service manual is not likely to even address this, since it would consider the compressor a unit with the clutch attached.

if the gap is excessive, from wear, and that is the only issue, removing a shim would do the trick. they are little skinny washers that set the gap between the clutch and the compressor shaft. the rebuilt clutch kit I ordered came with a little bag with a few assorted sizes. the clutch plate is attached to the shaft that drives the compressor. held on with a bolt. the coil and bearing are held on with snap rings.
 

meerschm

Member
Aug 26, 2012
1,079
jme2712 said:
To top this whole situation off my central air has a leak also. Talk about getting it from both ends.

Ouch.
 

CaptainXL

Member
Dec 4, 2011
2,445
jme2712 said:
To top this whole situation off my central air has a leak also. Talk about getting it from both ends.

We ended up buying a whole new split system last year. $3000. Turns out that the last HVAC technician that serviced the system left the service ports cracked open and the refrigerant slowly leaked out (bad valves) and burnt up the pump. I could have just got a new condenser unit but the lines had acid in them and the evaporator coil was old. So we just got a whole new system. I looked at my electric bill the year before last when the old unit was running during the summer and our kWh usage was double what it is now.
 

jme2712

Original poster
Member
Apr 30, 2013
29
CaptainXL;136108 said:
We ended up buying a whole new split system last year. $3000. Turns out that the last HVAC technician that serviced the system left the service ports cracked open and the refrigerant slowly leaked out (bad valves) and burnt up the pump. I could have just got a new condenser unit but the lines had acid in them and the evaporator coil was old. So we just got a whole new system. I looked at my electric bill the year before last when the old unit was running during the summer and our kWh usage was double what it is now.

Geez... I hope I just have a leak that easy to detect. 3k is a boat load! For my voy I hope that removing the shim will fix it. If not, off to the junk yard.

On a side note has anyone had issue with the arm rests on the door becoming loose or the bracket breaking?
 

meerschm

Member
Aug 26, 2012
1,079
jme2712 said:
Geez... I hope I just have a leak that easy to detect. 3k is a boat load! For my voy I hope that removing the gap will fix it. If not, off to the junk yard.

On a side note has anyone had issue with the arm rests on the door becoming loose or the bracket breaking?

You need a little gap...
 

triz

Member
Apr 22, 2013
746
jme2712 said:
Geez... I hope I just have a leak that easy to detect. 3k is a boat load! For my voy I hope that removing the shim will fix it. If not, off to the junk yard.

On a side note has anyone had issue with the arm rests on the door becoming loose or the bracket breaking?

I bought a new compressor with clutch for 187 dollars at Advance Auto.
 

jme2712

Original poster
Member
Apr 30, 2013
29
triz;136311 said:
I bought a new compressor with clutch for 187 dollars at Advance Auto.

What brand or does that matter? I'm trying to avoid evacuating the system at all costs. Gonna try to gap fix first. It was 61 degrees today and it was still acting up so I'm not sure if that is the issue. Any input?
 

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