Aircon fully gassed won't work !!! (1 Viewer)

[Hillview]

Hi all,

I have regassed my 100 properly with manifold gauges and vac pump, used 134a etc etc, checked all fuses, clutch on compressor works properly.

When turned on whether on recycle or direct from outside, all blowers and the compressor all works ! but no cold air ?

The vacuumed system sat in my workshop for literally 5 days whilst I went to London and didn't move a needle's width. So am a tad confused....

Has anyone experienced this before ?

Regards

Jonathan

 

[CorporalClegg]

Is the low side pulling a vacuum while the compressor is on? This indicates restriction, usually expansion valve.

if both high and low sides are at a static ~100 psi while compressor is running then you've most likely got a bad compressor.

 

[Hillview]

Hi Yes it is .... and quite well too

 

[CorporalClegg]

Hi Yes it is .... and quite well too

If the low side goes into a vacuum with compressor on feel the lines going up to and from the expansion valve if no temp change in to out of expansion valve replace it.

 

[CorporalClegg]

Low side should drop from static pressure to 20-30 psi when clutch cycles off.

 

[Hillview]

OK I can check that tomorrow or monday and come back to you ...many thanks

 

[Hillview]

Hi just thought could this be an issue with internal temp sensor ?

 

[CorporalClegg]

The clutch would not cycle if temp sensor is at fault. Weather it be the pressure sensor or ambiant air temp sensor.

 

[Hillview]

Thanks you, that's just sparked another thought, the clutch engages but doesn't cycle, due to the temperature isn't being met in the cabin

 

[CorporalClegg]

Thanks you, that's just sparked another thought, the clutch engages but doesn't cycle, due to the temperature isn't being met in the cabin

That's not why it would stop cycling, it cycles due to pressure in the system. If it's continually running with the correct amount of refridgerant the compressor isn't compressing and has worn seals and will need to be replaced

 

[Hillview]

OK .... is there any kind of test that I can carry out ? the manifold gauges showed the compressor kicking in at the right levels ....

 

[CorporalClegg]

What are the static pressures and the running pressures low and high

 

[jahawk]

I'd start with bypassing the pressure switch and see if it works.

 

[AlpineAccess]

What did to use to verify the R134 you added was at the correct pressure?

Too much or too little, won't run cold.

 

[Hillview]

Hi used a good set of manifold gauges, I can remember the actual pressure figures, but can reconnect during the week and check this when I get into my workshop again.

The vacuum held steadfast for 5 or so days whilst I was away in London, didn't move a needle's width !

I recharged to approx 1000g which seems to be the amount in the manual a member very kindly sent me. My only query; is 1000g correct for a car with no rear A/C control ? only front.....

 

[jerryb]

ummmm.. 24 or 28 ounces without rear, you do the math. I would verify that.

 

[flintknapper]

I recharged to approx 1000g which seems to be the amount in the manual a member very kindly sent me. My only query; is 1000g correct for a car with no rear A/C control ? only front.....

That would be about the correct amount for a unit WITH rear air.....but excessive for one without.

 

[Hillview]

Having looked at the manual there doesn't seem to be any other values.... if it were charged at 28oz that equates to around 750-800g.

Am I using the wrong repair manual ? would the extra 250g stop cold air being produced ?

 

[CorporalClegg]

Extra would cause high pressures and a short cycling clutch. Would be cold if the pressure switch allows enough time for clutch to cycle and gain enough pressure change. The actual pressures will tell you a lot of what's happening to continue to diagnose. If you've got cold and hot lines and good pressures you may have a blend door problem in hvac box. But when you say the clutch doesn't cycle you could have to little refridgerant or a bad compressor or a restriction.

 

[Hillview]

Thanks for you continued help with this.....

Tomorrow I shall reconnect the manifold gauges to check the pressures....what should they be ?

I'm thinking that I using the wrong repair manual if it says 1000g +/- 50g when it should be 750-800 (28oz)

Im afraid I dont under the cold and hot lines ...shouldnt they always be cold given it full of refrigerant ?