Rep Power: 145

Hello,

It has been some time since I've had to post here since I got my 2012 Civic but I am having some AC issues, so here it goes.

I was driving on the highway and needed to accelerate fairly quickly and had revved the engine to ~5k, nothing beyond its limits but fairly high, but only very briefly (<5s). After this, my AC stopped working.

I got home and had a look under the hood and immediately noticed a clunking noise from near the drive belt area. I used a piece of 1/2 poly tube to stethoscope the area and determined the noise is originating from the compressor area (no surprise). I've attached a link to a video I made. Sorry, it is a bit large (~60mb) so it may take a minute to load.

https://drive.google.com/file/d/1Bns...ew?usp=sharing

When pressing the AC button, there is no response on the compressor clutch, no signs of engagement that I can see. The clunking happens with or without the AC switched on/off; no difference.

I can freely spin the front part of the clutch assembly; it is not stuck, but does not engage with the AC button.

Question - Does this seem like a compressor issue or a clutch issue? Any tips or ideas on what happened or what is going on?

Full Disclosure - If you read my post history, I had a large rock fly into my condenser years ago. I replaced the condenser, dryer, PAG oil and had filled with R12a (an ~ replacement to R134a but a hydrocarbon mixture rather than 'freon'). This gas has leaked constantly since I replaced the condenser, could never find the actual leak (frustrating...) so i kept filling with R12a for now, I know, not ideal, but $$. I don't know if that has anything to do with my current issue but I thought I'd include it since I can't say for sure whether this has anything to do with the noise I am hearing.

Appreciate anyone's comments and thanks in advance.

 
Rep Power: 210

Did you try tapping on the compressor clutch while engine is running to see if it's possibly an out of spec air-gap issue that's not allowing the clutch plate to be drawn to the coil?

 
Rep Power: 145

Hi,

I got a pry bar down beside the clutch with the car running and AC system turned ON. I could not even move the clutch in at all, even with the car off, I cannot move the clutch in and out at all. I can spin the clutch freely but no horizontal movement (in and out).

I'm thinking more and more that I will likely have to just pull the clutch off and check it out. I'll try to get that done and report here what I find.

Thanks.

 
Rep Power: 210

Sorry for the late reply. Sounds like it might be the compressor coil or break in the wiring to the coil. Here's a Google search on coil testing: https://www.google.com/search?q=car+...obile&ie=UTF-8

 
Rep Power: 99

A little electrical troubleshooting should help to narrow down the cause of the problem (bad clutch, magnet, or wiring).

Remove the connector to the compressor, and then turn the A/C on. Measure to see if there is voltage at the connector terminals. There are three terminals, so you'll have to find out which ones are power and ground.

If the connector is difficult to get at, you could find the A/C relay ad remove it. Determine which pins are for the control side and which ones for the load side. Make sure you have the proper 12 volts feeding both sides. Then, you could jumper the load side and see if the compressor clutch engages.

Obviously, replace the clutch and/or magnet if you find that's the problem. Otherwise, it could be the evaporator temp sensor or the pressure switch. Maybe one those is bad or the pressure isn't enough to allow the A/C to kick on.

 
Rep Power: 145

Hello All,

I really appreciate everyone's input into the diagnosis into the issue here. I should check the clutch coil, but I'm mostly worried about the knocking sounds coming from the pulley area, I'm not sure that could be causing the sounds and it is extremely apparent when the car is idling.

I've gone ahead and removed the compressor clutch, thanks to @ezone and these awesome pics on this thread:

Is AC overcharged?

Now, I've got some question though....

1) The clutch plate was really hard to remove. Is this typical? I had to pry it off (note, not the pulley, the actual outside plate)

2) Do the (below) clutch plate and pulley look fairly worn?

3) I CANNOT spin the outside part of that bearing visible in first pic. I CAN spin the compressor, but the outside pat of that bearing is extremely stiff and I cannot spin it by hand. Should I be able to spin the shaft easily as well? I can only spin it when I have the clutch plate on, not as it is in the pic below.

4) Should the compressor shaft be able to move in and out (like how the clutch plate normally moves to engage the compressor)? How exactly does the clutch plate engage? How does it close the air gap? Is there a spring inside the compressor/shaft?

I just don't want to put another clutch and run into the same issue I was having. I guess I really never found the reason for the clunking. I'd really love some advise, hope someone has some insight here!

Thanks!

 
Rep Power: 210

Probably, because the shaft and the clutch plate are mated with metal splines which are designed to bind parts together purposefully to ensure there isn't unnecessary movement (i.e. inner cv axle shaft to differential). If the splines are rusted it will be more difficult to remove. If they are rusted use a brass wire brush (won't scratch metal) to clean them prior to installation.

doubtful the clutch plate could bend. It's made of solid metal and fairly thick, though I suppose it's possible? The more likely scenario would be the pulley's rubber connected to the inner bushing (shown in pic #3) could be cracked or worn? Seems to look fine in that pic but looks can be deceiving. Visually inspect it and try wiggling it to check for unnecessary looseness/play. Also, in pic #3 the pulley's outer (larger) diameter rubber doesn't look good..it's dried out and cracked which may cause a balancing issue. I think that rubber is there as a dampener for vibrations.
Cleaning the metal surfaces off with brake cleaner, or wet sanding with 600 grit (black/for metal) sandpaper would likely help make it more attracted to the coil.

I can't remember but you could call an auto parts store and see if they have one in stock and ask them to spin the shaft by hand to see if does or not.

The clutch plate is drawn to the coil via magnetism (the coil is an electronically controlled magnetic field generator). That's why the air-gap spacing between the coil and the clutch plate is so important, as too much space it will not be drawn to the coil and the compressor will not engage. Too little spacing the clutch will not release and the compressor will always be engaged.

Have you tested the coil?

When removing and installing the clutch plate, pulley, and coil try to avoid uneven pressure as it could bend the compressor shaft. I don't particular like the way (in the video) he used a mallet to tap remove the pulley. While he most likely didn't bend the shaft a three-jaw puller would be better if it can be fitted. IIRC when I removed a coil from a 6th gen Sanden (oem) compressor while the compressor was still mounted. For the pulley I couldn't fit a three-jaw puller so I used the claw side of two hammers. One at the 3 o'clock and the other at the 9 o'clock position to carefully/slowly and with even pressure to remove the pulley off.

Here's another way to test the coil:

Here's the video I used for my 6th gen:

 
Rep Power: 145

Actually, in that pic, the clutch plate is a bit bent, but this is because I was using a flat-head screwdriver and a mallet to pry the clutch plate off. I was prying one part of the plate, then turning the plate and hammering the screwdriver again to attempt to evenly remove the clutch. Well, I hope I didn't bend the compressor shaft, though I don't think I did, but I'm sure even a slight bend can put everything off balance. The plate came mostly straight off, I don't think I ever applied enough pressure to put the shaft out of centre, I guess I will find out when I put the new pulley and clutch on. Hope I will be able to get an even separation between pulley and clutch plate, I'll use feeler gauges.

So, I brought the pulley in the house and had a closer look. When I spin it, I definitely hear a metal grinding/scratching noise. The new pulley is much smoother than the old one and is completely quiet. Hoping this bearing was the culprit of the knocking/clunking.

I do a lot of highway driving in southern Ontario (Canada) and there is just so much salt on the highway during the winter. I cringe every time I have to pass a single salt (or brine, yea, they actually spray salty water on the road before a snow storm). It does so much damage to the body and all the parts, even with getting the greasy undercoating every year. I wouldn't have been able to get this far without my electric impact wrench (just for loosening, I'll torque everything back on by hand to spec).

I guess what I'm wondering is, there is no in and out movement of the actual compressor shaft to engage/disengage the clutch, right? It is essentially the warping (slightly, whatever the distance the shims move the clutch plate away from the pulley face) of the clutch plate, due to the draw from the magnet, to contact the pulley surface, is that correct?

As for the coil, that is on my to-do-next list, just have to get back out to the car, hopefully in a day or two, definitely before the new parts go on, huge contrast with old and new:

 
Rep Power: 210

The compressor shaft does not move.

Concerning the clutch plate you are correct when the coil is engaged. I'm not sure about when the coil is turned off but my guess is that once power to the coil is stopped centrifugal force powered by engine rotation to the compressor pulley widens the the air-gap between clutch plate and pulley. The pulley always spins wether or not the compressor is switched on.
I could be totally wrong about that, maybe those that know will chime in?

As much as possible pry on opposite sides of either the clutch plate, pulley, or coil at the same time with even pressure to remove. Same when installing.

 
Rep Power: 222

The pulley will spin with the rest of them, clutch plate will be stationary until engaged

 
Rep Power: 99

1. I would imagine that's normal. Since they are splines that come together, they will tend to seize over time in your kind of climate. Sort of like a CV axle shaft that needs to be pounded out of the hub, right?

2. I'd say they look pretty worn, but I've never disassembled a compressor so??

3. I don't believe the outside of that bearing is supposed to move. Isn't it pressed into the bore? I'd imagine it is just like a front press-in wheel bearing. The outer race of the bearing stays stationary while the inner one spins. It bears the weight of the shaft.

Regarding the clutch plate in-and-out movement, either the clutch plate has some sort of slide in its assembly (I doubt that) or the plate just flexes to engage with the pulley. I doubt the shaft moves in and out.

 
Rep Power: 145

@bachands @Wankenstein @Colin42 Thanks for the info about the clutch, I think I understand the operation now and how it engages. Crazy that the metal actually flexes slightly to engage, I guess that magnet is pretty powerful.

On that note, I finally got the coil out, I had to get some needle-nose snap ring pliers but it come out really easy once I could reach the ring. So, coil reads a totally open circuit, dead, good thing I bought a new one.

This is so strange though, two problems arise at the same time? That is, both the coil died and the pulley bearing went bad at the same instant. I had never heard the clunking before this issue, and the lack of engagement of the clutch started with this clunking. (I'm under the hood a lot, checking..... damn chipmunks make nests on top of the exhaust manifold).

Anyway, now that I am ready to out the pieces back on, I do have one concern. When I put the clutch plate back on and check the air gap, what happens if I have to adjust the air gap? I had a hard time pulling the old clutch plate off, I am hoping that the new one will go on and off a bit easier, in case I have to add/remove shims. If I have to pull the new clutch plate off, I am not sure how I could do it gently enough so as to not damage it. I guess I'm not asking a question here, but looking for advice on what others have run into when adjusting the air gap. Should I thoroughly clean the splines on the compressor shaft?

Thanks everyone.

 
Rep Power: 222

Definitely clean up the splines

 
Rep Power: 210

Yes, clean the splines.

Gap too wide to engage = reduce shim thickness.
Gap too narrow = increase shim thickness.
Find the correct air-gap spec online or in manual and try to achieve that.

 
Rep Power: 145

Hi All,

OK, I got out to the car this weekend and got the new coil, pulley and clutch on. The snap rings were a bit of a pain, in terms of making sure they were all the way into the groove but I believe it is all secured well. I got a good gap on the clutch/pulley and my compressor is engaging very well, very quietly and no more knocking noise from the pulley area, mostly success.... I do have the service manual for the clutch replacement (purchased a "day-pass" from the Honda website) and made sure to get the correct air gap (0.3-0.6mm) and to "break-in" the new clutch by cycling the A/C ~20 times. I should have read the thing about NOT pulling on the clutch face when taking that part off since it clearly states it in there, but it seems I did not do damage to the compressor shaft.

I also replaced a noisy idler pulley (aftermarket, and I may have already regretted that) and put a new belt on (from Honda), for good measure. However, the new belt seems to be making a noise. The noise is an intermittent buzz that increases/decreases with engine speed/belt speed. It is not a squeal, but more of a high-pitched "bizzzz........bizz........bizz......bizz". I have to identify exactly where it is coming from, but from what I understand, this could be due to a misaligned pulley? The noise occurs independent of the A/C clutch engagement, no change in the noise when engaged vs disengaged. I can try the old belt and see if that makes noise too, but I am thinking it could be just a crappy aftermarket part causing the issue ("Dayco" idler pulley, maybe... not too sure yet). It sounds like the belt is scraping along some surface somewhere along the way. I've never replaced a serpentine belt before, is this a 'common' issue? What would be my best approach or what should I expect to have to do to fix this?

Thanks!

 
Rep Power: 210

I'm not familiar with 8th gens but this video shows previous and current routing of the belt. I'm not sure if this applies to your repair but worth double checking. If it is routed correctly then misalignment could be the issue. Loose belts can cause squealing but that's generally not an issue with serpentine belts that are tensioned by an auto-tensioner.