Air conditioning condenser fan runs continuously with A/C on (manual type)

[guest164]

I have a 2010 iShift which has covered 130,000 miles (in March 2015). I've had the car from brand new and it's been fantastic.

Like members are constantly reminded I do run the A/C at least once a week and in my case for at least 20 minutes.

I have had two "problems" with air conditioning before my current problem:

1) fan constantly runs - low gas pressure - it was re-gased - an the problem fixed.
2) fan constantly run - a unspecified corroded switch - cleaned and problem fixed.

Now these two things happened a few years back. The problem I've just got is I have a constantly running radiator/condenser fan (with A/C on) but the gas pressure is OK and apparently the system is sort of 'OK'.

The "sort of" comes from the garage reporting that the issue is that I have is a corroded a/c clutch. Has any one heard of this? I don't think any disassembly was done by the garage so I don't know how they have come to the conclusion.

I have a question for those folks from temperate climates in Northern Europe and drive a mark II Jazz with manual air conditioning - in winter say at +5deg C, when you switch on your A/C does the a) radiator and condenser fans cycle on/off every 8-15 seconds and b) do you hear the metallic click of the air conditioning compressor clutch engaging and disengaging every so often? That's what I think happened for me too but my memory is useless!

You see what I need to know is what's normal for manual a/c on a Jazz (mark 2) in winter time at about 5 degrees C? What I'm getting is the radiator//condenser fans running all the time and I think I hear the click of the a/c compressor clutch when I first switch on the A/C with the A/C button but I don't think I'm hearing the clutch clicking on every so often whilst the A/C is on as I think it used to do.

So here I am, thinking,  do I go for what's proposed by the garage, which is to replace the A/C clutch? I did see another posting on this forum with someone else having this fix recommended. But, having an Internet search about A/C clutch replacement, it's not really a common thing to need to have done. And, since I'm careful to maintain the A/C by using it at least weekly, I'm wondering why it needs done and even if it's the right solution!

And - and this is a biggie - if there are lots of you out there running your A/C carefully at least once each week to keep it working - then if looking after it that way leads (eventually) to an apparently corroded clutch and a 500 GBP Honda Dealer bill to replace the A/C clutch (or less, at a non-franchised somewhere else) then it's still a shock!

So. Put your thinking caps on folks and let's reason this one through. The gas pressure is OK and the compressor is apparently running and there is some cooling - difficult to notice when it's just 5 degrees C, ambient.

So what then, other than the A/C clutch, could be wrong? What do you reckon?

And if it is the A/C clutch at fault due to the corrosion on the clutch surfaces then is the Honda garage telling me that the A/C compressor is always "on" because it's not pumping fast enough to be effective?

Hold that thought! Ok, say that is what's happening, well wouldn't that mean the A/C clutch is going to get pretty hot since it would have to be slipping. And, if it's slipping wouldn't the "corrosion" be scraped off by the rubbing of the A/C clutch on the A/C compressor's pulley?

So I'm hoping one of you out there is a secret A/C expert - who knows all the aspects of a car's A/C system from receivers, evaporators, driers, low and high pressure switches, control relays and the role of the car ECU in controlling the solenoid that energises the electromagnetic A/C clutch and all that,  and say "ahh, I saw this back on an ol' '10 plate Jazz. It's the ...."

Thanks for your help and for reading this. Let me know how your A/C behaves at 5decC - radiator/condenser fans cycling, A/C clutch clicking on/off regularly? Or like me, constant fan running and (apparently - although not convinced) A/C compressor running all the time?

Duncan.

[culzean]

The clutch is just a magnetic coil and a friction plate that it attracts when power is applied to it.  Air gap between fixed and moving faces (one attached to pump and one to moving pulley) is important as if gap too small the clutch may not release properly and slip and get hot, and if the gap too big the magnet may not be strong enough to attract the other plate so no drive will be transmitted to compressor.

Maybe the corrosion is stopping the plates moving freely and making contact,  so although it has power applied to it the compressor is not being driven, thus the heat exchanger radiator fan will keep running for as long as the aircon is switched on,  but clutch power will remain on because no cooling is taking place.

try running with aircon off and check temperature of 'cold' (low pressure) side metal piping under the bonnet ( the to left upper side of engine bay, the one with blue plastic filling cap sticking out just above ABS unit and to left of brake fluid reservoir) - then turn aircon on and see if pipe gets any colder.

[VicW]

First of all the A/C will not work at all at temperatures below about 4C, it's a safety feature to protect the A/C system.
The condenser fan should cut in when the compressor starts, that is when the pressure is low. The on/off cycling time is about 8-10 secs on/off but this can and does vary.
With the bonnet open, A/C off, blower fan anywhere but off and the engine running try and observe the compressor clutch, you may need a torch, and get a helper to operate the A/C switch. You should be able to see if the clutch engages and disengages. You may not hear it because of the noise of the fan. Mind your fingers !
If it is permanently engaged then I suggest that the A/C system needs properly servicing not just re-pressurising. That means it being done by someone who has the right equipment and knows how to use it. The system has to evacuated to determine how much is left, therefore how much is missing. This may indicate a leak but will depend on how long it is since the system was last serviced.

Vic.

[guest164]

Thanks culzean.

I spent some time making the checks you suggested.

I first took the car for a ten minute highway drive in ambient temperatures of 6 deg C without AC running. After stopping I left the engine running and checked the pipe you mentioned. It felt about the same temperature as the ambient air temperature. I then ran the AC for five minutes and the pipe didn't feel appreciably colder.

During this time the condenser and radiator fans ran continuously from the time the AC was switched on until I gave up checking the temperature.

Duncan.

[guest164]

Thanks Vic,

Try as I might I couldn't determine whether the clutch was engaging/disengaging when A/C button was cycled slowly  off and on every 30 seconds or so. I had the interior fan set to the 1 position. Engine was idling and coolant was at normal operating temperature. Ambient air was 6 deg C.

As before both condenser and radiator fans run continuously when A/C switch was on.

From looking down at the pulley end of the compressor from above it looks like the whole end is moving as one mass. Switching off the A/C doesn't seem to make the "inner" part of the pulley stop turning if that makes sense.

However I'm not really sure what I'm looking for so perhaps I'm misreading what I'm seeing.

I'm soon going on a longish trip and I'm worried what might be the consequences of the compressor being permanently engaged (i.e my observation is that irrespective of the A/C button position the clutch from my albeit skewed, compromised view, is connecting the pulley to the compressor).

I'm confused. My recent visit to my Honda dealer whom I've no reason to mistrust has told me that the A/C is fine but, yet it's acting unusually.

One thing that would reassure me is to hear what your A/C would do at a low ambient temperature near the 4 deg C limit that's been mentioned. What happens when above that temperature and what happens below.

For instance, if air temperature is say 0 deg C, what happens when the A/C is switched on. Does the light in the switch not light and the compressor, and external fans stay off? Understanding this might help me understand if what I'm experiencing is normal A/C operation when the air temperature is too low to operate.

Thanks for any help you can give.

Duncan

[tonytan]

hI
Sounds to me as though you system is low on refrigerant hence the evaporator is not cold enough to cause the compressor to cycle on and off at regular intervals. Also you mentioned that your low pressure pipe feels at ambient temperature when in fact if the system is running correctly it should feel cold/chilled to the touch. On the other hand the high pressure pipe should feel warm/hottish when running normally. There is a failsafe whereas if you run out of refrigerant completely there is a pressure switch mounted on the receiver drier unit that will cut off the compressor to prevent damage to it due to a lack of lubricant in the refrigerant. In your case there is just enough refrigerant in your system for the compressor to carry on running but not enough to drop the temperature at the evaporator to cause it to cycle at regular intervals. The idea of the compressor cycling is to prevent freezing/icing up of the evaporator. Take you car either to your dealer or a air con specialist the will do a regas which consists of evacuating what is remaining in your system (they can then tell whether it is low on refrigerant) check for leaks by carrying out a vacuum test and if all is fine then put back the correct amount of refrigerant. If there is a leak especially if its a bad one it will show up on the vacuum test then one will have to find the cause of the leak and rectify it before refilling it with refrigerant. Hope all this helps.

[guest164]

Hi Tonytan,

First thank you for your suggestions - your diagnosis was completely correct.

As I mentioned in a previous post the low pressure pipe didn't feel cold to touch.  I called my Honda dealer who was happy to take a look again.

I mentioned to the dealer about my concern about the compressor being engaged constantly. Not only did they take my concern seriously they took me into the workshop to show the clutch engaging/disengaging. I had to admit I had been looking at the wrong component. The compressor is mounted very low and is quite difficult to view.

Since I was at the dealer I asked about the compressor and condensor fan running constantly whenever the AC was switched on. I also said that the low pressure pipe didn't seem to get cold. They said I might have a borderline low pressure issue and suggested I booked the car in for an A/C service.

The A/C service was done and included old gas removal, a 15 minute vacuum test and a regas with new gas, replacement PAG oil and a UV dye. The vacuum test passed. The dye was added as a diagnostic aid if there is any future leak. The original gas pressure was mid way between minimum and maximum.

After the service, the operation of the air conditioning was exactly how I remember it working  prior to the constantly running fans problem. At 5 deg C ambient, the fans/compressor cycle - running for 6 seconds and then off for approximately 20 seconds.

Problem solved.

One remaining observation is that, assuming constantly running condenser fans and compressor isn't normal, it is worth listening out for those fans when you run your air conditioning. If they're running all the time then it might be a good idea to get your gas pressure tested and put back up nearer the maximum.


I'll certainly be checking the length of time the fans are running and if the are on more time than they're off then I think that'll be the time to get the system checked and topped up.

Thanks to everyone. D.

[Jazzdriver]

Why was the gas pressure low?  Was there a leak?  If so, has that been fixed?

[guest164]

Hi JazzDriver,

Great question and it's something I've wondered. I guess the short answer is yes there are leaks but they're not ones that are fixable.

Sounds odd but, from my nonspecialist, layman's view, my understanding is that the A/C pipework is made up of hard metal pipes and flexible hoses. I think it's often the joints between these that are the leaky bits.

I also think that's why we're encouraged to run our air conditioning regularly to keep the oil lubricant to circulate enough to help seal the joints by keeping things in good condition.

The vacuum test that gets done by the regassing phase of the A/C service, I'm guessing, has the downside that it sucks in everything so that those bits that can move are pulled tighter together than they would sit under pressure. Of course, if you have a proper hole there is no way its going to hold a vacuum for the fifteen minutes test that's used in the automated air conditioning service recharge cycle.

In my case, the system had held sufficient pressure to cycle the compressor & condenser fans on/off properly for at least one and a half years since my last A/C re-gas. I've been trying to remember how my A/C was behaving  just before it started running the compressor and fans constantly. I think the compressor and fans were switching on for say ten seconds and then off for may be five or so seconds. Certainly the pattern had changed enough to be aware of a difference.

To keep the A/C in shape, I've always run the A/C for at least twenty minutes once a week but only when the ambient air temperature on the day was warmer than 5 degrees C.

I've decided to change this maintenance approach to run the A/C each weekday for at least ten minutes irrespective of the ambient temperature. I'm going to rely on the A/C system's sensors to stop running if the evaporator would block due to ice formation. I'm sure Honda would have designed it so the driver doesn't need to know when it's safe to use.

For my own interest I'm going to keep a record of the time the compressor is on against time off relative to ambient temperature to see if I can judge when the optimum moment is to get the system gas topped up.

A final, general observation to the forum, I try to get the best fuel economy I can, so running A/C more frequently is going to make a dent in the fuel efficiency. I'm going to note the changes. Currently I get approximately 55-58 MPG (imperial) in winter and 62-65 MPG in summer. Hopefully this won't change too much.

D.

[VicW]

A final, general observation to the forum, I try to get the best fuel economy I can, so running A/C more frequently is going to make a dent in the fuel efficiency. I'm going to note the changes. Currently I get approximately 55-58 MPG (imperial) in winter and 62-65 MPG in summer. Hopefully this won't change too much.
D.

Dunk,  May I suggest that you leave your aircon on all the time as many on this forum already do. The effect on fuel consumption and performance is almost negligible with a modern system regardless of what the 'greens' would have you believe. What little difference it makes to fuel consumption is easily recovered by more judicious use of your right foot, a small price to pay for the convenience and comfort of aircon all the year round.
If it wasn't designed to run all the time it would be temperature controlled to only switch on at higher temperatures than it is now.

Vic.

[culzean]

I think the idea of running it regularly is to keep the pump shaft seals lubricated and supple (which is probably the biggest leak point on the system unless you get a hole in the condenser ) , If you do let your aircon system run out of gas and the system pressure drops too low the system collects moisture and corrodes inside - you will end up with a very big bill if you want to get it working again.

I buy Halfords regas kit and just blow a little gas + oil in each spring,  never had a problem with the aircon on any car I have had.

you can notice the difference in power when overtaking if you turn aircon off before you do it,  but otherwise if you are just pootling around probably no big deal on the MPG figure. 

I hate the way the system doesn't remember the manual settings you had set up before you selected auto and vice-versa - you have to set everything up again when auto switched off - surely a choice of auto and manual should be there so that switching between them puts everything back where you had it set last time would be better.

[guest164]

Hi Vic,

Thank you for your advice -  it's good to know that modern A/C doesn't have as big an impact on fuel economy as in older systems.

Eventually, I  hope Honda will adopt electric A/C  compressors on the Jazz. I like the idea of doing away with that expensive magnetic clutch  arrangement for one thing. I'm sure Honda's current A/C implementation errs on the side of conservative design - better to be old school and reliable than cutting edge and unreliable - but, still, it feels that there's room for improvements in the implementation of the manual type A/C systems like the type in my Jazz. I can't comment on the automatic, climate control type fitted in the more upmarket Jazz models. Perhaps it's much smarter and aids fuel economy.

I will try running with A/C on for the majority of my two hour daily drive but I'm going to leave it off until the car reaches normal operating temperature - no sense adding more load when the car is in the warm up phase and is using more fuel - and I'm also going to switch it off about twenty minutes before my destination so the evaporator has a chance to dry out. Don't want those nasty, smelly bacteria to grow whilst the car isn't running.

Also it's a fair point you make about the evaporator thermostat having a higher switching temperature if the compressor and fans weren't designed to run all the time. The thing about that is I've convinced myself that it's not normal for the compressor and fans to run all the time. In all the times except when the A/C is misbehaving the system cycles the compressor and fans on/off - usual 5-10 seconds on and may be 20-10 seconds off. Mind you I've only had the Jazz in maximum ambient air temperatures of 28 degrees C but even then the compressor and fans cycle on and off albeit after about 1 or 2 minutes of initial constant running to establish the evaporator temperature.

Anyway from now on I'll be paying attention to the cycling of the compressor and fans as the ambient air temperatures rise from our Scottish spring time 5 degrees C to Cornish summertime, summer holiday temperatures of 25 degrees C (hopefully). I'll try and update my blog with the results.

[guest164]

Hi Culzean,

Thanks for the wise warning about shaft seals being the biggest cause of gas leakage.

Hopefully that's something I can avoid from now on by yearly air conditioning services. I'd rather pay £80 (UK) once a year than pay nearly £1500(UK), parts and labour, for a genuine Honda compressor. The car will soon have depreciated in value to less than that - high mileages do hit hard and I've already passed 130,000 miles.

And luckily so far I've avoided flying stone damage to the condenser. Also the A/C has never be so low on gas that the fans and compressor don't operate so hopefully I've not overwhelmed the drier and as a result have moisture in my system. From what you say, moisture in the system would be seriously bad news.

Thanks for your advice and help.

D.

[culzean]

Eventually, I  hope Honda will adopt electric A/C  compressors on the Jazz. I like the idea of doing away with that expensive magnetic clutch  arrangement for one thing.

The benefit of things driven by an electric motor is they are not dependent on engine speed don't have to be either on or off - they can be anywhere in-between which means they can run fast or slow and aircon can be much more controllable and energy efficient (although i doubt you could run aircon with engine stopped as it would flatten your battery pretty quickly.   

I have an inkling that modern cars have sensors to disconnect the magnetic clutch  when you are starting the engine and when you floor the accelerator,  but can't confirm that as mine still seems to have a bit more overtaking power when i turn aircon off - may be placebo effect.