Air con problem? Advice on Service?

[peterljohnson55]

My air conditioning system does just fine, 95% of the time. But on really hot days it just fails to cool. It will start to cool and after a while it will stop cooling. Dunno what causes this.

Anyway, I figure the system is due for a service.

So, can members please let me know...
1) what may cause the problem above, and
2) what factors do I need to consider when negotiating for a professional system service?

Thanks heaps

[kempy311]

What sort of ks on it?

[peterljohnson55]

kempy, I got it at 91000 and it has now done 155000, all relatively easy miles and no extreme heat conditions.

I don't have any idea of previous aircon service history, unfortunately.

I intend keeping car for another 8 years so not too concerned about investing $$$ in service of aircon.

[RG]

Sounds like it's either low on gas or the compressor is failing.

[kempy311]

Couple of things listed in order of likely hood.
1. Low on gas small leak somewhere
2. One or more of the fans isn't working correctly causing over pressure and the aircon to cut out.
3. Compressor lazy/worn out
4. Partial blocked orfice tube.

[JimStone]

Originally Posted by kempy311

4. Partial blocked orfice tube.

Back in the day there was an 'in service repair' for this issue identifing orifice tube as culprit

[RG]

Originally Posted by JimStone

Back in the day there was an 'in service repair' for this issue identifing orifice tube as culprit

Just be careful when clearing this tube as what comes out of it does not taste good at all.

[mif73]

All good points above,

Depends also if the compressor is still engaging (clicking in and out in cycle) or not when the cooling performance drops.

If low on gas it should stop the compressor coming on.

If you have the interior fan on full and the coldest setting, the compressor should be running almost constantly.

Otherwise perhaps the heater tap is stuck open or the blend door is on the heater side? (engine warming up and then hot water comes through heater).

Good luck with that, and remember to use the aircon regularly even in winter, at least once a week.

[peterljohnson55]

Thank you guys for your advice. At least it doesn't seem as tho the unit is stuffed, just needs some attention.

IF I do find something conclusive I will come back and let you know the result.

Thanks and regards, Peter.

[pks54]

Hi I posted a problem with my AU2 XR8 last year like the problem you stated in your first post. The A/C worked then cut out. The compressor would then not engage pressing the A/C button on and off until I turned off the engine then turned it back on. It would then work again for about 5 to 10 minutes then cut out and not come back on again.

Took it to many a/c places and they could not find the problem due to it being mainly an intermittent problem, and sometimes the thing just dammed worked when I took the car back to them. I could not work it out.

After spending many dollars the thing is still not fixed. But I'll be ****ed I discovered that if the fan is on the highest setting (setting Number 4) the a/c works all the time and does not cut out. But if the fan setting is on like number 1 or 2, the problem starts again.

So these days the fan stays on full blast while the a/c is on. It is a bit noisy because the fan is running full blast but atleast its cold in the car on those hot days.

Beats the hell out of me why it does it, but maybe try this and see if its like mine.

[peterljohnson55]

Originally Posted by pks54

But I'll be ****ed I discovered that if the fan is on the highest setting (setting Number 4) the a/c works all the time and does not cut out. But if the fan setting is on like number 1 or 2, the problem starts again.

So these days the fan stays on full blast while the a/c is on. It is a bit noisy because the fan is running full blast but atleast its cold in the car on those hot days.

Beats the hell out of me why it does it, but maybe try this and see if its like mine.

Thanks pks54, that is invaluable. I will give it a try -- by doing things as per normal, and if it cuts out, then stop the engine, restart engine and air-con and put it immediately up to highest. (Highest fan speed shouldn't matter as it is the hottest days that it does this). Does that sound like a good approach?

Thanks again. Peter.

[mif73]

Originally Posted by pks54

Hi I posted a problem with my AU2 XR8 last year like the problem you stated in your first post. The A/C worked then cut out. The compressor would then not engage pressing the A/C button on and off until I turned off the engine then turned it back on. It would then work again for about 5 to 10 minutes then cut out and not come back on again.

Took it to many a/c places and they could not find the problem due to it being mainly an intermittent problem, and sometimes the thing just dammed worked when I took the car back to them. I could not work it out.

After spending many dollars the thing is still not fixed. But I'll be ****ed I discovered that if the fan is on the highest setting (setting Number 4) the a/c works all the time and does not cut out. But if the fan setting is on like number 1 or 2, the problem starts again.

So these days the fan stays on full blast while the a/c is on. It is a bit noisy because the fan is running full blast but atleast its cold in the car on those hot days.

Beats the hell out of me why it does it, but maybe try this and see if its like mine.

Perhaps the evap is freezing up and it turns off the compressor at low fan speeds.
May not have enough airflow over the evap at low fan speed and possibly needs a.clean?

[BLU-220]

you could try and reset the blend door?? if that helps
see the link for more detail

cheers dean
http://www.fordmods.com/documents.php?d=9

[pks54]

Originally Posted by peterljohnson55

Thanks pks54, that is invaluable. I will give it a try -- by doing things as per normal, and if it cuts out, then stop the engine, restart engine and air-con and put it immediately up to highest. (Highest fan speed shouldn't matter as it is the hottest days that it does this). Does that sound like a good approach?

Thanks again. Peter.

Just see if at low fan speed if the air is not blowing cold pull over and stop the car but not the engine. I tested to see while the engine is running that by pressing the a/c button I could not hear the click noise the clutch makes to turn the compressor on. I also actually saw that the when the problem was happening pressing the a/c button was not turning the compressor on. See if by turning the engine of and then back on then pressing the a/c button actually turns the compressing back on. You should be able to hear it click back on. Bad thing though is it only last another 5 mins.

I don't think I have tried it once the a/c has failed to turn engine back on and try it at full blast. I just discovered one day that that the air con was working all the time when the fan was full blast. So I just always know that when I want a/c its just the way it has to be.

Yes, I have tried it at low speeds since and it still has the problem. I guess now its to late to go back to the a/c shops to tell them as its been over a year.

I know how you feel. I was this close to selling the car because of it. Sounds stupid but it annoyed me that much. Just see if its what I described. As to a fix I can't help you there.

[pks54]

Originally Posted by mif73

Perhaps the evap is freezing up and it turns off the compressor at low fan speeds.
May not have enough airflow over the evap at low fan speed and possibly needs a.clean?

Thanks, but what is the evap and where can I find it?

Cheers

[peterljohnson55]

Originally Posted by pks54

Thanks, but what is the evap and where can I find it?

ditto.

[kempy311]

I think you really need to take it into someone who knows what there doing.