johndeerebones

I have been a full time student for a year, a tech for 15 years before that.

Today our temps were ~110*, hotter than it's been for 20 years at least. Of course my AC decided today was to quit. Lets just say the 50 mile commute SUCKED. When I left school it seemed ok, sucks at first then cools down fine down the road, normal for this car. Then maybe 5 miles down the road it quit all together. I didn't expect to be anymore than mediocre on temps like they were, but not to not work at all. When I got home I burned the crap out of my arms a few times to diagnose it...

Here is what I found, 4 pm, around 110 ambient: The radiator and condensor fans were running fine with the a/c like they are supposed to. The compressor was not engaged at all, my pressures were evened out at ~150 psi (a little high?) I had power to the red/blue wire to the clutch, but it wasn't engaged. It was to hot (engine) to dig around the exhaust and the smoking hot power steering to get a probe stuck in the thermal switch wires and test it.
Fast forward to ~10pm, ambient 80*: I went to my niece's baseball game so it had an extended cool down... I turned it on and it worked perfectly. The first thing I did was stick a thermometer into the center vents to check that. I stuck a screw driver in the throttle linkage and ran it at ~2000 rpms for an hour and a half. I already had my 134 gauges on it from earlier so I just left them so I could watch the pressures. With the clutch engaged, it read ~15 psi low side, ~200 psi on the high. Cycle times were 8-10 seconds usually. The vent temps stayed at a constant 40*, cycled on or not. It ran perfectly for an hour and a half tonight, yet today it quit all together. Being heat related I am sure either the clutch is breaking down when it's hot or the thermal switch is opening to low, but I can't fix what I can't find..... Any ideas?

ezone

Wow, I didn't see this last night before I went to bed.

I'm looking up an 01 Civic, correct?



Here is what I found, 4 pm, around 110 ambient: The radiator and condensor fans were running fine with the a/c like they are supposed to. The compressor was not engaged at all, my pressures were evened out at ~150 psi (a little high?)


150 static pressure is ok, considering the ambient + engine compartment heat.

Fans running says to me that the clutch relay is supposed to be turned on by the PCM, so you go to the relay and test.

You had power on the clutch wire, so...




I had power to the red/blue wire to the clutch, but it wasn't engaged. It was to hot (engine) to dig around the exhaust and the smoking hot power steering to get a probe stuck in the thermal switch wires and test it.


Thermal protector on an 01 only interrupts the circuit for the clutch, so the fans should still run.

(Later models have the thermal protector in series with the pressure switch, so the entire system would have been shut down by the MICU.)


Fast forward to ~10pm, ambient 80*: I went to my niece's baseball game so it had an extended cool down... I turned it on and it worked perfectly. The first thing I did was stick a thermometer into the center vents to check that. I stuck a screw driver in the throttle linkage and ran it at ~2000 rpms for an hour and a half. I already had my 134 gauges on it from earlier so I just left them so I could watch the pressures. With the clutch engaged, it read ~15 psi low side, ~200 psi on the high. Cycle times were 8-10 seconds usually. The vent temps stayed at a constant 40*, cycled on or not. It ran perfectly for an hour and a half tonight, yet today it quit all together. Being heat related I am sure either the clutch is breaking down when it's hot or the thermal switch is opening to low, but I can't fix what I can't find..... Any ideas?

Ok, temp is great at 80*amb. The AC thermostat is making the compressor cycle, so the system gets the evapoator nice and cold.
I wouldn't touch the charge.




You had power to the compressor: Hopefully that narrows it down to the compressor area.

**Was it full B+, or was it a lot less? A test light would still light up at 8V but that might not be enough to run the clutch. Just saying. Relays get pitted contacts, that makes a voltage drop.

I have been tricked by a bad relay many times.

--------------------------------------------------------


**Thermal protector went open circuit.....Generally it is a one-time-use deal. If it trips, it gets replaced.
IDK....Bypass it? Jumper the wires together?

**Clutch coil going open circuit when hot. Will work again when cooled off. May quit at certain temperatures, may be intermittent for a while until the broken wire ends in the winding can't touch anymore.
I have done a couple clutch sets this year (other cars) for just this issue.

**Bolt holding the coil ground wire on top of the compressor came loose?
Also there is a Bullet connector between the thermal protector and the clutch, has a rubber boot on it.

Those would give an open circuit or really high resistance when ohm checked from the relay socket.




**Clutch plate gap:
Clearance:
0.5±0.15 mm (0.020±0.006 in.)
Too wide would cause it to quit engaging when hot. Magnetic field strength drops lower with heat. There are shims to adjust the gap, under the plate.


That's all I can think of ATM, HTH

sdaidoji

iTrader: (1)

wow...
johndeerebones and ezone in one thread...
me watching to see where these crazy guys goes

johndeerebones

The fans were turning, so check on that. The compressor wasn't coming on. The power was at the wire itself, about were it goes down the side of the radiator fan. The power there was a full battery 14+ there, with my Power Probe. (I love that thing, pretty versatile tool. Being a tech too I would highly recommend one. A good DVOM is good too, but they are great too.) The only thing after that is the thermal protector, and the clutch itself. I am leaning toward the clutch itself... It has been noisy when engaged every since I bought the car, not positive that isn't the compressor itself though. I was confident I didn't want to add any the high side was high enough psi. Wasn't sure about evacuating a tad, but the cycle times would suck then. Wasn't thinking the charge was the culprit anyway. The air does suck, but the car is a sauna, the a/c is barely adequate anyway, and the heat and lack of humidity here is rediculous. AC works off of humidity, dry air means they don't work well, this is also why swamp coolers are more prevalent in deserts, AC don't work there....
It is so hot I am afraid to drive it and have it screw up again... 1 year out of working in the heat and getting older has made me a sis, I CANNOT take the heat now. I need to replace the pins holding the front air damn on, only reason I haven't checked the air gap yet. It will take 30 minutes to get the air damn off and 5 secs to check the air gap..... I have to drive an oring pick into each on with a small hammer and pry them out to get them out. If it didn't screw up the airflow around the engine bay I would leave it off. Seems like you are in agreement, I am going the right way, just too hot to lay on the drive and work on it right now unless it screws up again...... Thanks for your help, I will keep it updated, but it may be a day or two before I get enough motivation to fix it
Not only that, money is really tight after a year off work, and time is even shorter.....

Just for knowings sake, is a clutch worth it? Most of the time a new complete compressor is more cost effective....

ezone

the clutch itself... It has been noisy when engaged

CYM, I got a note about that I sent you.
You may be hearing slippage, if the gap is too big.

the a/c is barely adequate anyway,

Yeah, too low capacity for the amount of cabin space they are supposed to cool.
There was a TSB on 8th gens early on about how the dark cars wouldn't stay cool while driving down the road (or something like that) because of undersized rating, but I think it has been removed.


AC works off of humidity, dry air means they don't work well, this is also why swamp coolers are more prevalent in deserts, AC don't work there....

Um, not really. Job #1 of any AC system is to dry the air.
It has to dry the air before it can cool it. Humid air condenses on the evaporator coil as it passes through....then it gets cooled.


-------------------------------------------

You gotta think about airflow speeds, and how much time air actually gets to spend IN the evaporator to shed its heat and moisture:

You have an evap core that is only about 3 inches thick....in real humid weather, the first 2" may be needed to condense the moisture out of the air...now there is only the last 1" to cool that same air with.
This is why God invented RECIRCULATE! Now it can try to cool off (inside, cabin) air that already got most of the moisture removed.

With DRY air, more (larger surface area) of the evap coil can be used to actually cool the air.

HOWEVER, effin hot humid air is far more miserable than effin hot dry air, when it comes to personal comfort. AC makes a more noticeable difference on your skin to a person in a humid environment than a dry one.

----------------------------------------------------

Back to drying the air:
This is how a dehumidifier works: All a dehumidifier is is a small air conditioner, all self contained in one box. If you could remotely mount and cool the condensor outside of the dehumidifier, the rest of the unit would blow cold air from the evaporator just like an air conditioner.



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Swamp cooler use in dry areas has absolutely nothing to do with your theory of "AC don't work there...."

Swamp coolers are used in the dry areas because they consume far less power than a regular AC system, and deliver a substantial cooling effect. Lots of "bang for the buck".

Swamp cooler works on principles of eveporative cooling (so does sweating). Moisture doesn't evaporate rapidly in a humid climate, so it doesn't work there nearly as well as in a really dry climate, where moisture evaporates quite quickly.

It is cheap and effective in the right climate.



just too hot to lay on the drive and work on it right now

I refuse to lay on the ground for any reason now. As long as I have a hoist available (at work).

I always wanted to have a hoist installed in my own garage, but I would need to raise the ceiling if I did......and then people would never leave me alone. I hate people.



Just for knowings sake, is a clutch worth it? Most of the time a new complete compressor is more cost effective..

Yeah, as long as the compressor works. Sounded like yours is fine.
See the note I'm PMing you.

I would trust an original compressor far longer than any reman from the aftermarket.

Over my career I have had sooooo many problems with remans that didn't last one year it ain't even funny. Usually leaks. Maybe not all of them, but certainly enough to consider myself "burned" by them.


HTH

johndeerebones

Thanks for the info. My clutch makes noise when its engaged, not when its disengaged. I am thinking its the compressor itself that's noisy, but not gonna condemn it without some diagnostics.

The symptoms fit clutch probs though. Maybe the noise is in the compressor, but the problem is in the clutch idk.

The moisture from the air is a side effect of the air conditioner working. Temperature conducts a whole lot better through water than it does air. For instance, say 50% humidity air looses 20* through evaporation, water, and 10* through air to air. In this example there is less loss through a dry environment... Not arguing for the sake of arguing or nothing, keep in mind, just bouncing theory around. The theory is the same as body heat type stuff too. Say it's 0* and you go outside nude. Cold I know, now, get out of the shower and do it wet. Hypothermia will sit in a whole lot faster now.... Liquids conduct heat much better than air. The principle of AC is to remove heat from the air. This is also why recirculate works so much better. It is blowing cold air out, but it is also pulling the hot air from the cab. Instead of just cramming cold air on top of hot air in a not recirculate mode. This is also the science behind "hot air" returns in your house.

I'm with you on the lift. It was a real bite to pull the transmission on stands... Was able to get it two foot off the ground, but it still sucked. Two post lifts arent that expensive anymore. When I get out of school and start working again I am gonna build a shop, seperate from my house.... It WILL have a lift in it..... You can get two posts for around a grand now....

I have little faith in remans too... You do get what you pay for in most instances. The reman stuff is the cheapest for a reason...

I always wanted to have a hoist installed in my own garage, but I would need to raise the ceiling if I did......and then people would never leave me alone. I hate people.

LOL that is funny stuff. I am the same way at times. I am pretty sure mechanicing does that to you. It is daily apparent that the world is overtaken with idiots when you are trying to explain anything mechanical to them.....

ezone

Umm.....be in a HOT TUB outside when it is freezing out. You can stand up and calmly walk in the house without freezing your nads off. The warm water is insulating you from the cold air (briefly).

For the LOLz.

04 Honda Civic

iTrader: (2)

Watching where these crazy guys go.. they are in a hot tub then there running around naked freezing their nads off.

ezone

The weather reports have warnings for swampass all week.

It rained here yesterday, the air should dry out a bit after the water boils off.

johndeerebones

LOL its really hot here to. Too hot to work on my car when it seems to be working, now watch it will quit again the next 50 mile drive I have in these temps. Newton's law or something... It has been 105-110* for over a week. We usually have humidity out the hind end, but it is extremely dry here, no real chance of rain for a couple more weeks. The drought here is the worst we have had in as long as I can remember, 31 years old.

The slipping would make since for the noise, but it doesn't show it at all on the gauges. When it kicks in and out the pressure changes are immediate, and it runs high enough pressure that it theoretically would slip often.... Don't know the extreme heat could sure break the magnetic field down enough to not engage it fully, makes since. Thanks for the thoughts.

ezone

I usually associate noise (while the clutch is engaged) with compressor internals, but I found that article that explained the possibility of slippage making noise so I sent it to you.

Your complaint along with unusually high temps sorta match a field coil/weak mag/excess clearance problem.

johndeerebones

The air has been working great until now... Another retarded hot day and it quits, again. Anyway worked on it hotter than crap again, to not have the same scenario as before. I pull the drivers wheel off and the air gap was .020" or real close all the way around. Switched the relays with the left head light relay to rule it out. No change, headlight worked fine. The resistance of the clutch coil to ground was 5.6 ohms, it was about 100* and I have about 1 ohm in my leads. With the engine off so I could hear it I used my powerprobe to power up the wire to the clutch and it engaged. Started it up and couldn't get the clutch to engage. I am leaning to the thermal protector, but it is so covered up by the alternator I can test it, Tonight when it cools off I am gonna pull the alternator and make a test wire to go around the thermal protector for a test....

ezone

If it was an open thermal protector, you couldn't have made the clutch engage with the power probe unless you bypassed it. The protector is in series with the clutch power wire on an 01.
Where did you stab that wire at?


Where did you stab that wire at?




WAIT A SEC
Found this handy info:
NOTE: The thermal protector will have no continuity above 252 to 262F (122 to 128C). When the temperature drops below 241 to 219F (116 to 104C), the thermal protector will have continuity.


Again: Where did you stab that wire at?







Here's another tidbit:
Field Coil Resistance
3.05-3.35 ohms at 68 F (20 C)
(Remember, resistance goes up with temperatures.)

johndeerebones

Here it is 1000 and I just got home. Wait two more ***** to cool down, no thanks. Have to work on it later.Ya I got the temp specs in my pc tech manual. I stabbed the wire on the clutch side of it. I just ohmmed it from the relay terminal receptacle all the way to where I stabbed it earlier. I had 0.1 ohms there, yet tryed to run it and had zero voltage there. It is too stinking hot to work on it. I am gonna try to park it so I can work on it while its cool for once....

BlueEM2

iTrader: (1)

I'm having the exact same issue. The only thing I've done so far is change the clutch relay. I'm thinking mine is the clutch assembly also but I can't rule out the compressor. However, I'm betting the clutch is much more likely to work intermittently than the compressor. Sometimes I go for a drive (1 hr) and it works the whole time. Sometimes it works for 10 minutes of the drive, sometimes it doesn't work right off the get go.

ezone

Run with that bet, it will pay.
A compressor isn't going to heal itself intermittently, but the electrical parts and clutch may.

johndeerebones

Piece of junk! Took the car on a vacation, filled up with the wife and kids and it quit of course. It worked for 2 hours + then quit for the last 45 minutes. It worked fine for that long going 75 mph down the highway. Traffic was jammed up and we got slowed down for 5 or 10 minutes and it quit all together. I know the ECM has the authority to shut down the a/c if it sees an overheat, but the temp gauge never moved. The fans still work fine both the radiator and condensor fans, swapped around relays, checked fuses. No tools with me now and I am 250 miles from home. I know after it sits it will work fine like it has since the last time it quit. I am leaning more and more toward the clutch.. If I do it I am jumping that thermal switch to. The older I get the more I hate not having a/c.

ezone

Can you reach the thermal protector and just mash a vampire clip across its wires? (just a band-aid thought, no clue if you can really reach it)


GIS for "vampire clip" came up with this (I am not kidding!):

BlueEM2

iTrader: (1)

Don't change the clutch, change the coil. I just realized that the clutch comes separately and costs around 155. The coil is only around 67 and is the part that is far more likely to fail.

johndeerebones

Ezone, good idea, but I cant get to it w/o pulling the alternator...

Blue, good to know. Especially now, money is tight. Ya the friction part of it is fine, it is the coil that isn't working at times...

ezone

I don't remember if you checked the gap.....(was trying to think of a quick, unobtrusive way to do something to any part of it, that's why I said the vampire clip)
a clamp on ammeter wrapped around the single wire going to the compressor would quickly tell if something was going open circuit or not.
If the amp reading didn't change when it quit, then it wasn't an electrical failure, and the gap must be too big.

Can't fix it with that, but could give a direction.

johndeerebones

No info to add except I have been too broke to work on it, I think it is the clutch coil. The only thing I have to add is that I was just going through a powerpoint I had from my AC education and ran into some of what I was saying about the humidity thing. It explains it a little better than me.....

Air Conditioning and Comfort
*
The purpose of an A/C system is for customer comfort. The A/C system achieves this comfort level by cooling the temperature inside the cab and by removing moisture (humidity), dust and pollen.
*
The human body cools itself by pushing moisture to the skin’s surface and allowing it to evaporate. This is why you feel cool when getting out of a swimming pool. The moisture on your skin is evaporating. When moisture evaporates it cools the skin. (Additional example: Alcohol on the skin evaporates and feels cool.) Dip thermometer in alcohol and wave in class to see temp drop start with alcohol at room temp. ( Great Demo )
*
The relative humidity governs how quickly this evaporation process occurs.
*
·******** When the relative humidity is high, the air is already saturated with moisture and is less likely to take on more moisture. Thus there will be a low evaporation rate, and your body feels warmer. Your skin will feel warm, and may even become moist from this lack of evaporation.
·******** When the relative humidity is low, the air has very little moisture in it. It will take on moisture more easily through evaporation. Your skin will be cool and dry because all of the moisture has evaporated.
*
By removing moisture and lowering the humidity, the A/C system can achieve customer comfort at a higher temperature. Test show that people feel just as cool at 79°F with 30% humidity as they do at 72°F with 90% humidity.
*
In addition the moisture that is removed from the air condenses on the A/C evaporator fins. Dust and Pollen will tend to stick to this moisture as the air passes over the fins. The dust and pollen will be flushed out the evaporator drain with the water. This is why people with allergies feel more comfortable in an air-conditioned area.

With the addition of filters the pollen and dirt is absent as the air passes thru the evaporator, keeping the condensation tube clear of mud