Thread: On/Off Air con compresser

First the daft questions ?

Is it getting cold ?

Have you got the temp set at minimum ?

What fan speed (internal) are you running it at ?

There are a few home tests you can do to 'almost' determine if the gas charge is low.

Run the system - then whilst running touch the following

The bigger pipe on the compressor (suction) it should be fairly cold
The smaller pipe on the compressor (careful it could be quite hot) and it should be hotish - if it;s extremely hot the system may have a blockage or unlikely but too much gas - if it isn't all that hot the system could be short of gas.
The pipe that leave the condenser - where it enters the filter/drier (normally has the sight glass and pressure switch attached - black cylinder about the size of a decent beer can) this pipe should be warm to the touch. If it's hot check the condenser fans are running -
Then where the suction pipe re-enters the engine bay through the fire wall - this should be cold.

Another test - if you have a test meter - is test the volts out of the pressure switch whilst it's running - if when the compressor stops the volts drop to zero - then it's tripping on pressure - it may be high pressure not just low.

Another test - run for a very short time only - disconnect the wires from the pressure switch and bridge them with a small piece of wire - if the compressor continues to run - then it indicates low or high pressure (low or high on gas) blocked/no air flow through the condenser = high pressure, a blocked filter/drier can cause both high and low pressure faults - depending on the type.

Originally Posted by ladas

First the daft questions ?

Is it getting cold ?

Have you got the temp set at minimum ?

What fan speed (internal) are you running it at ?

No...Not dumb Q, I should have said all that but Ive got a bad habbit of talking, talking and Talking and going on & on & on & on & on etc and making the post very long and boring

1) Is coldish but not really ice cold.

2) yes temp on min

3) usally 1-3 (D1a)

Ive been told its normal , ie runs thermomallilly or something

Do you think it would be worth a few $ to get it looked at anyway, kind of a service as it were?

How often does it cut in / out

From a normal start up, from when you first put the ac on at the beginning of the day - how long before it cuts out.

Do you have a simple home thermometer - pop it into the outlet - and see what the min temp it reaches before it cuts out. Do this test with the windows/doors shut and the air on resurculating. It should go down to at least 10 Deg C at the outlet.

Are you running it on recirc? If so & depending how often it cycles off, it may be normal having caught up with the internal load.

If not, what ladas has said ^ ^ ^

Originally Posted by ladas

How often does it cut in / out

From a normal start up, from when you first put the ac on at the beginning of the day - how long before it cuts out.

Do you have a simple home thermometer - pop it into the outlet - and see what the min temp it reaches before it cuts out. Do this test with the windows/doors shut and the air on resurculating. It should go down to at least 10 Deg C at the outlet.

1) usally cuts out after a few minutes

Ok so the outlet you are talking about in a air outlet in cabin, Im guessing that .

Also a dumb Q here, Im guessing that if on reculate it takes less time to cool because the air in the cabin is being moved through the system over & over?

Should it be used on that setting all the time?

On a hot day (28 Deg C +) it should take about 10 to 15 mins to cut ot the first time - then back in and out every 2 - 5 mins.

The face air outlet on the dash - the bit where the cold stuff should come from

You shouldn't - in my view - run on recirc all the time - not that it affect land rovers too much - but on cars that are very air tight it can lead to oxygen starvation - the recirc should be used first off when you start to get the inside cold then switched over to fresh - unless there is a great deal of dust/smoke etc., outside - but I try and use fresh air as soon as I can - doesn't get so cold but it's better quality air (most of the time)

Try the thermometer test - and let me know what the temp is when it cuts out.

and yes on recirc - them same air (plus any air that leaks in) will be turned over time and time again - thus cooler air entering the ac = cooler air leaving (or for the technical it's called the Delta T difference between in temp and out temp)