dinsum

Hi!

I purchased a 2003 4 door civic dx in the winter and noticed last month that my A/C doesn't work.

When I hit the A/C button the light turns on and the rpm raises a little, both fans come on but the problem is the clutch does not like to engage, but I found out that as long as I turn my A/C on before my engine warms up the clutch always engages and works great! so as long as I turn on my A/C when the engine is cold and leave it on it never turns off and I get nice cold A/C but if I turn off my A/C after the engine is warm 95% of the time it will not turn back on until the engine cools off....

Things I've done/tested:

Checked the Pressure in the system (Its good, around 40-50 PSI on low side when compressor is running)
Checked Pressure Switch (works good)
Checked Clutch Relay and A/C Fuses (All good)
Checked Thermal Protector (Jumped the Two Wires, no difference so it works)
Checked the In-Dash Diagnostic by holding the circulation and rear defrost buttons at same time and putting car in ON position, no codes show up

What is the next things to check? field coil and clutch clearance gap?

I noticed that the little grounding bracket that holds the thermal protector in place is rusted pretty bad and there is a ground wire going to it that looks like its coming from the grounding side of the field coil? Maybe I will try to run a ground wire to it from a good known ground location to see if that helps any

Any suggestions are appreciated, Thanks!

ezone

Fans run so the system is TRYING to run the compressor.....

Get it to quit working so you can do a few checks.
Leave engine running and AC system turned on so it's running the radiator fans


Open the fusebox in the engine compartment.
Tap on the clutch relay hard a few times with a screwdriver handle, see if the compressor clutch kicks on again.
If it kicks on it needs the relay.

If not,
Then I'd pull out the relay and check powers and grounds in its socket, and see if I can jumper the terminals between power and clutch coil and get it to click on.
If no, then I'd ohm test the coil circuit right from the same relay socket in the fusebox.

If there's something like 3-4 ohms then I'd assume the coil is ok and it's grounded.

shut the engine off.
Then power the coil up again with the jumper...It's an electromagnet, so I would use a long steel screwdriver and see if it will try to stick to the clutch plate or pulley. If it tries to stick ....
Then I'd try to push the clutch plate against the pulley and see if it will stick and grab on its own.
If it sticks now, then I'd suspect excessively large gap between the outer clutch plate and the pulley.


How many miles on the car? 200k ish? Wear of the clutch and pulley surfaces can cause excessive clearance and make this happen.

dinsum

Thanks for the pointers ezone! they are all really good

Few days ago I tried swapping the clutch relay with the horn relay which didn't make any changes and also tried jumping the relay socket pins which didn't engage the clutch either.

I will do the ohm test, if it checks ok then I will jump the pins again when the engine is warmed up and see if the clutch likes to engage

Im leaning towards the problem being clutch plate gap, my car has 300,000 kilometers on it

Is it possible to change the shim sizes for the clutch plate through the wheel well without taking the belt off? just wondering in case it comes to this

Cheers

ezone

That's loke about 190,000 miles so it's a real good possibility.

Spec for the gap is 0.50 mm +/- 0.15 mm.

I use a dial indicator to do setup or checks because after they wear in and get grooves in the surfaces a feeler gauge doesn't measure accurately.

I'd think you can probably eyeball the plate movement and tell if it moves in and out a lot more than a half-millimeter.
Manually power up the clutch, engage and disengage several times while watching it move.


Yes. It may take a little work, but I can do it.


I did one real high mileage worn out 6th gen car earlier this spring with complaint of inop AC---- clutch gap was just huge --- removed plate and removed all the shims and that got the gap close enough to work again--- for now.
The pulley was badly 'dished' where the plate rides.

dinsum

hoping to get a friend to help soon to short the pins so I can see what the clutch is doing but from what i remember i could visually see a gap that looked to be between 1-3 mm, ill measure soon just so busy at work lately

I see that there is armature plate holding tool for taking the nut off, is this really needed? I was thinking my impact gun might do the trick... Is there any tricks to holding this plate without the tool?

ezone

Impact will remove the nut if you can reach it.

I wouldn't impact it back on though, you could snap off the compressor shaft (expen$ive). Torque to spec.

I can hold that plate still with a big set of Channellocks if needed.

dinsum

Also I was wondering how much thickness worth of shims is behing the armature plate from factory? Lets say my gap is 2mm, will there be enough thickness worth of shims behind the armature plate to remove to bring it to spec or is there a different method if thats the case?

ezone

The number and thickness of the shims varies, each setup can be different. You'll just have to see what's in yours.

dinsum

A/C stopped working a few minutes before i got home to I figured it would be a good time to test

All wires are ok, there is about 4 ohms resistance through the field coil, manual says it should be around 3 ohms so i guess 4 is fine with warm engine and 75 degree weather

When i jump the pins for the clutch relay you can hear a little bit of sound coming from the compressor but it does not engage, so I hit the end not too hard with a breaker bar and it would engage, so its pretty much guarantee'd the problem is the field coil itself or the clutch gap, after seeing the difference of the clutch engages vs disengaged it looks like for sure the gap is over 1mm, looks almost like 2mm but hard to tell from the top of the car by eye without using feeler guages but for sure the gap is large.

When I have free time I will jack the car up and remove the driver side wheel to see if I can access the little bugger through the wheel well. I will remove as much shims as I can to get it to a 0.15mm gap, hope it fixes it

dinsum

Ok i decided to just go and try now, was very easy

just jack the front end up, put some axle stands, remove the wheel, remove two plastic retainers to pull the plastic cover back and there is quite a lot of room for access, so i used my impact, came off no problem. There was only 1 shim behind the armature plate, i cant seem to find my vernier caliper but the shim matches up with the 0.020" feeler guage I have, tightened everything back up and the gap looks a lot better, i think its within spec now, tried jumping the pins and it was working good but the engine is cold right now, so I will go for a little cruise tonight and see what happens

Thanks for all the help so far ezone, appreciated

ezone

0.15mm would be way too tight.

The acceptable range would be 0.35 to 0.65mm on a new clutch. (.020" +/- .006")


I guess at this point all you can do is leave out the shim and see how it works, and hope it lasts a few more seasons before it needs real money thrown at it.

dinsum

Oops I read the manual wrong, thought it said the gap should be between 0.15mm - 0.5mm

Just found my vernier and the shim is 0.53mm, the gap looks about half the size that it used to be and i checked the gap with my 0.020" feeler guage and it was a snug fit, so I think taking the shim out may have fixed everything, I just got home from a long drive and the A/C turned on everytime I tried, nice and cold but I wont know for sure if its fixed until the next hot day but everything is looking promising

Glad I took the time to do this myself instead of sending into a shop like a lot of people suggested, I was thinking about it, even though i got a good amount of experience working on cars the A/C system was something I never wanted to mess with but it was a good learning experience