[flamecycle]

Just a few seals here and there, and a quick reset with one of Storey's cables, and the air bags are inflating like they should.

Now it's the A/C. I'm finding that it quits working when the temperature gets above about 90 degress f. or so. It sounds a lot like the three way switch adventures listed here http://rangerovers.net/newrremedies.htm#airconditioning on the common fixes page. When the temperature is lower, the A/C runs like a champ for hours on end. I've had it recharged, pollen filters are cleaned (although my new ones are on order since I'm due for my annual filter swap).

Has anyone had similar symptoms caused by anything BESIDES the 3-way switch? And when I go to swap this thing, I'm suspecting the system will need to be evacuated, right? Shop manuals are not exactly clear on this point.

thanks!!!

 

[Jos Geuze]

Hi

Just posted a reply regarding the overfilling with gas.

Too high pressure (is the same as too high temperature) in the condensor is most likely the cause. Check the temperature with an infrared temperature reader and compare it to a similar car with proper functioning AC.

viewtopic.php?f=3&t=33025

Too much gas can give the symptoms you are describing. Of course it can also be the switch itself that is triggered too early.
Proplems with the heat transfer in the condensor like blocked or bend fins, not proper working fan etc leads to the same too high pressure in the condensor.

For reference you might want to look in the diagram like:

http://www.ent.ohiou.edu/~me321/quiz.in ... _r134a.gif

In the banana shape the properties of liquid and gas together are displayes with the upper line 100% gas and the lower line 100% liquid. You can see that the temperature is constant at a constant pressure within the banana. If you download a more detailed HS diagram you can exactly pinpoint what pressure you have in your condensor and even check it with the pressure gauge at the gas filling station. If pressure and temperature are not matching the data from the HS diagram you might have the wrong refridgerant or the system was not properly vacuumed before it was filled.

I hope this explanantion helps.

Regards

Jos

 

[lrscott]

The switch is a possibility. I would wait for a hot day when the A/C isn't working right and see if the compressor is operating properly. If the clutch is engaging like normal but, you are noticing it not being cool enough in the car, then it is an issue with the gas either being to high or low in the system. Mine does this when I run the compressor for to long in hot conditions. I recently fixed my leak but, I know I either under or over charged the system for the trial run.

 

[flamecycle]

Good suggestions. I did, however, watch while the local oil change place evacuated and recharged the system with their big fancy automated tool, so I'm confident the charge is correct. I'm pretty sure it's switch related as when the compressor is actually engaged, the air is cold. So either there's a switch out of whack, or some other input into the equation is out of spec so the compressor is not even being energized.

I'm currently following up on the fact that I don't see the condensor fans running. It's a switch somewhere. Now I just wish I had more that 3 minutes to look at the thing...

 

[flamecycle]

oh, and by the way, the pressure switches do indeed require evacuation of the refrigerant. Makes sense, because I couldn't imagine how a switch could detect the refrigerant pressure without actually contacting it, but since I'm not an AC expert, I'm just checking my assumptions.

 

[AMcK]

One other one - I had the same problem while on holiday in France in temps over 30C. Found the heat was affecting the operation of the clutch. My temporary cure to keep cool whilst on hols was to poor some cold water over the clutch to cool it - it would then work.

 

[redrange]

I just had a similar aircon issue, to much pressure/temperature, worked out my compressor was shot! also have you still got the viscous engine cooling fan??

 

[flamecycle]

Just to tie up this thread and leave some value in it in the archives....

Once I finally broke down and took it to my indie, the thing we found was that the pressures in the system were off. The high side was low, and the low side was high. So even though the AC was working like a champ WHEN it was working, once the ambient temperature passed 92 degrees, something got far enough out of whack that the compressor would turn off. But it took us forever to pinpoint it to the compressor because it hasn't been that warm of a summer this year, so the problem had to get worse before it got better. And I don't know about you guys, but for me, leather seats are great until the A/C quits on a 95 f. day. :shock:

After the first trip when they did initial diagnosis, checking all the basics (like is there really refrigerant in the system? Yes. It was off by only 1/4 oz). They did change the 3-way switch like I asked. But it was 3 weeks before it was warm enough to happen again. We drove 6 hours to visit family, went 4x4 a whole day, and made it 5 1/2 hours back before it acted up again.

But finally it began happening as low as 70 degrees, and the shop was able to see it happen, and unfortunately determined the right part to be the compressor. So far so good, been cool ever since.