CrossCountry

I have a 95 Honda Civic, and the clutch on the compressor is not turning.
With engine off, I can turn it by hand.
When I turn on the car & start air conditioner, the belt turns, the fan turns. Both sides of the compressor turn, but not the silver end part, which, someone told me is the clutch.

Do I need a new compressor, or could something else be wrong?

thanks for your help.

CrossCountry

From the little I've learned, in order for the clutch to engage, there has to be enough freon in the system, but to get the freon in, the clutch has to engage...

So, what's the correct way to manually engage the clutch so that freon can be added???

mk378

That is not true. Enough refrigerant can be added with the compressor off to close the switch and make it start by itself. Jumping stuff to make it run when it shouldn't is asking for trouble.

Additionally, if it has leaked down to zero, there's a serious leak and merely recharging is not going to last more than a few minutes, hours, maybe days if you're lucky. The leak would need to be found and repaired. Don't be tempted to try a "stop leak" product-- its very bad for your system and they usually won't stop leaks.

If I were working on the car I'd start by checking if 12 volts is reaching the compressor clutch wire. If not, then check the pressure and the relay. If 12 volts is reaching the clutch, check the clutch for continuity (3 to 4 ohms from the wire to ground), if that is OK the gap must be too large, which can be adjusted.

If you don't have a gauge set you can check if there is enough pressure that the compressor should run by unplugging the pressure switch and checking the switch for continuity. It should be closed circuit. If you find the switch is open, you may want to have a shop work on finding the leak.

CrossCountry

The freon was at zero because I replaced the evaporator and dryer.
I used a vacuum pump, and there don't seem to be any leaks.
I attached a can of freon, the can never got cold, and I never saw any bubbles in the manifold gauge, so I took the gauge back and asked if it might be defective, and they said that the freon wouldn't be drawn in unless the compressor kicks on, which the clutch doesn't engage...

I do not know which relay is for the clutch, it's not listed under the hood.
I don't know where the pressure switch is that you mentioned.
Let me see if I can find the volt meter....

mk378

Draw a vacuum again. Close both wheels on the manifold gauge and disconnect the vacuum pump, connect can tapper and tap a can. You can safely charge liquid into the high side as long as the compressor is not running. This is how new cars are charged at the factory. They don't even know if the A/C is going to work until the test drive some time later. So, engine off, open both wheels on the manifold gauge and hold the can upside down. (the engine is again OFF when you do this.) You should be able to empty almost a whole can into the system that way (if you do empty a whole can, tap another can and keep going). Once it stops going in by itself, CLOSE BOTH WHEELS and observe the pressure on both sides should be well above 50, which is what it takes to close the switch. Start the engine the compressor should engage. Finish the charge through the LOW SIDE ONLY as usual. I think it takes 18 oz which is 1.5 cans. Don't over charge.

That sight glass found on some (mostly cheap) manifold gauges doesn't really serve much purpose. Just look at the pressures.

The switch should be mounted on the condenser. Unlike the plastic switches on American cars, this switch cannot be removed with the system charged. Clutch relay on a 1995 is mounted on a bracket next to the condenser and left headlight. There are two relays there, the other one is for the condenser fan.

fcm

If you pulled a proper vacuum, there should be no problem charging the system with the correct amount of refrigerant, compressor does not need to be running.

What kind of gauge "set" do you have?

The A/C pressure switch is on the receiver, [filter/dryer].

You can check the pressure by testing for a ground in and out of the pressure switch, [with A/C turned on] or even continuity across the two terminals at any time. 94

CrossCountry

thank you both for your help.
I rented the gauge from autozone.
Probably I messed up the vacuum... it's confusing because the wheels clipped onto the high & low side on the car open one way, and the wheels near the manifold gauge open the opposite way.... And then one needs to spray some of the freon out of the top of the yellow hose, (to get rid of the air in the line) which I'm not sure I did...

Does a can of freon always get cold when using it, or is it possible for the freon to come out of the can without getting cold?

CrossCountry

So.... I vacuumed it again, let it set for a long time... no leaks. Charged it with the engine off. The clutch now engages - THANK YOU!!!!!!

It took maybe half of a can, it's barely cool. I turned on the car and tried charging it more, and it doesn't seem to do anything.

The guage above the blue is at 105, and the guage above the red is at 90.

Why would it not take more freon in, and also not be cold???

Former User

Is the clutch engaging with the engine running while trying to add refrigerant?

mk378

Let's review manifold gauge 101.

Make sure the set is assembled properly. The blue parts are the low side, they go on the smaller quick connector on the car, which is in the line between the evaporator and the compressor. The red parts are the high side, the larger quick connector on the car. The different sized connectors encourage "idiot proof" usage, but with most manifold sets it is possible for some idiot to attach the wrong coupler to the wrong hose during the pre-use assembly.

The gauges always register the pressure in the blue and red hoses, which is the pressure in the car if the connectors are properly engaged.

Opening the valve wheels on the manifold below the gauges connects the blue or red hose to the yellow hose. They should only be opened when necessary to add or remove refrigerant or to evacuate. They must be CLOSED for accurate pressure readings.

To add refrigerant with the compressor running, you must leave the high side valve wheel closed and open only the low side one. The high side wheel should never be opened with the car running.

CrossCountry

Yes, the clutch engages with the engine running, a/c on, while trying to add freon.

Yes, the blue line goes between the evaporator and the compressor.
The red line goes between the condenser and the compressor.

What should the gauges read, ideally?
How do you know if you have too much freon or too little freon in the system?

Thamks for your help.

Former User

If you used the gauges correctly, then the compressor is toast.

mk378

I want to back way up and ask why you ended up replacing the evaporator and drier.

As for what pressure to charge to, don't. Starting from empty and charging by weight is best. So based on that you know there is not enough.

And you're sure the valve wheels on the manifold are both closed when you read these pressures?

CrossCountry

Styrofoam flew everywhere while using the a/c, so I opened up the evaporator to replace one of the styrofoam pieces... (since the a/c was just cool but not cold, I thought maybe the lack of styrofoam was the culprit.) Then the bolt on the evaporator broke, and I couldn't remove the partial bolt, so I purchased a new evaporator and installed it.

I changed the drier because I've read that if the system is opened for any length of time, the drier should be changed.

I'm not sure how the wheels were when pressure was read... I'll set it up again later.

Thanks for your help.

tony_2018

wtf...styrofoam? PLease give more details.

edit:

Did you replace the thermostat in the evap? Still don't know how the foam could've start falling apart, never seen that happen. I've seen mold growing on it, but not fall apart.

Also did you properly oiled the evap?

fcm

Honda Automotive Parts #7&8 are Styrofoam insulation, it can deteriorate and be blown out of the vents, not that uncommon.

When adding refrigerant with engine and AC on, add it to the low side. 94

CrossCountry

No, I did not change the thermostat in the evaporator... maybe that is the problem - Thanks!!!

The styrofoam insulation was very deteriorated, kinda scary when it blew at me through the vents, and everyone I talked to said it couldn't have happened because there wasn't styrofoam inside... made me feel like I was crazy until I found a picture similar to the above link.

No, I didn't put paeg oil in the evaporator, there was too much put in the compressor, so I figured it would even itself out.

The gauges are goofy, they were at about fifty. I opened up the low wheels and tried to add more refrigerant with the engine and AC on, no refrigerant would go in / the can didn't get cold, so I shut off the engine, opened and closed the gauges a few times, now they say the pressure is 90 & 95 with the wheels closed.

What should the gauges say?

If the system isn't evacuated, and you pull a vacuum, does the vacuum pull out the freon? From what I've read it sounds like the paeg oil stays in the system.

Anyone know?

mk378

90 with the compressor off is about right (it will vary with temperature) When you start the compressor the high side should go up and the low side go down. When you open the low side wheel with a tapped can connected to the yellow hose, the low side gauge will go up because you're reading the pressure in the can. Leave it open and you should see the high side rise as the system charges.

Again for accurate pressure readings, both wheels CLOSED. Do NOT open the high side wheel ever with the engine on. It is used only to evacuate or initially charge with the engine off, but should be closed all other times.

When you evacuate, all gasses (air or refrigerant) are removed but the oil generally stays put.

94eg!

iTrader: (2)

FYI: The reason you must charge your AC system by weight instead of the readings on the gauges is because those readings will stay the same once liquid refrigerant is present in the system. Once the internal pressure builds enough to condense the refrigerant into a liquid, the pressure stabilizes. From that point, the only thing that will alter the pressure readings is turning the system on/off, OR the ambient temperature changes (higher temps = higher pressure).

Procedure:
- Begin with engine off!
- Hook up manifold gauges to empty system (vent everything out if it's not empty)
- Open "wheels" at the snap fittings
- Hook up compressor to yellow hose
- Turn on compressor
- Open both manifold "wheels"
- After 15 minutes of vacuuming, close manifold "wheels"
- Turn off vacuum
- If vacuum reading on gauges holds for 30 minutes proceed (if not, you have a leak)
- Remove Vacuum, Tap new can of refrigerant and hook up to yellow hose
- Purge air from line with valve on yellow hose (if available)
- Slowly open "wheel" on low side of manifold
- Slowly open "wheel" on high side of manifold
- If can will not empty completely, it's time to close the high side "wheel", start the motor and engage the compressor
- Once can is empty, close the low side, tap another can and attach to your yellow hose
- Open the low side again and continue filling (use hot water if necessary).
- When you've filled your system with the recommended weight of frigerant, close the low-side wheel and do a performance test on your AC system.
- Once complete, close the wheels on the snap fittings and disconnect everything from the car

BEST TIP: Due to the pressure drop, the can won't empty if it gets too cold (cold = low pressure), get a pot of hot water and lay the cold can in it. The hot water will bring the pressure back up and the system will begin drawing out refrigerant again. This happens because the can pressure drops lower than the low-side pressure. The hot water will get ice-cold very quickly so get more if needed. Shops don't have this problem because a giant cylinder of refrigerant doesn't ice over & loose pressure like a tiny can.

Here is the 94-95 civic System Performance Test chart I traced out of the book. I added more lines in to make it more accurate and useful too. You can use this image in MS Paint fill out the chart. It's easy to fill in, just draw a line up from the ambient temp at the bottom. Then draw horizontal lines where that line intersects your "relative humidy" (google your local weather) on each of the 3 sets of diagonal lines. You should be +/- 10% on all the readings it points to on the left (vent temp, high-side pressure & low-side pressure). If anything is out of whack, the book can help you diagnose.

94eg!

iTrader: (2)

As an example on the chart, if it's 95* outside with a relative humidy of 30%, you should be measuring around a 57* vent temp, 37psi low-side, and a 320psi high-side.

Test is conducted with the car in the shade, front doors open, AC on max, vents set to recycle inside air.