Air con info

freelandie71 · Dec 21, 2013

Hi all. Not sure if my air con is working properly. When turning it on air does not feel very cold. I have checked the air con pressure and it is reading just short of 35psi. It worked ok in the summer but does it work differently in the winter?. Also the fans do not run in the engine bay when a/c is turned on like it did in the summer. The compressor is running as the idle needle rises a bit when turned on and lowers when turned off. Thanks.

Epicuser · Dec 21, 2013

Lots to do with the ambient temperature. I would not expect the fans on unless it was hot outside.

As long as the outside temp is over about 5c then it should work.

I'm sitting in mine with outside temp at about 10c, with heater on cold (seat heater on) and the air coming out is ....... Cold but not ice cold like it is in summer.

The a/c system was checked a couple of weeks ago and it was all fine.

Tiercel · Dec 21, 2013

My A/C is a bit weedy all the time. I believe theyre linked to an external temperature sensor or something like that.

Even in the height of summer my A/C cooled the air a little but certainly not ice cold, and that was just after getting it serviced and refilled as it had sat idle all winter and leaked all the gas out.

longdog · Dec 21, 2013

Could be the fan control unit thats faulty, unplugging the engine temp sensor should bring them on by default.
The only outside temp sensor is for the fbh.

freelandie71 · Dec 21, 2013

longdog said:
Could be the fan control unit thats faulty, unplugging the engine temp sensor should bring them on by default.
The only outside temp sensor is for the fbh.

Thanks for the replies guys, where about is the engine temp sensor on a td4. If I unplug this and fans run then them the control unit is ok or does this method just to prove the fan themselves work.

Datatek · Dec 21, 2013

The aircon shouldn't need the fans in this weather, certainly not when first put on.
Probably low on gas and of course it doesn't work when the air temperature is too low.

Nodge68 · Dec 21, 2013

The fans on the Freelander and many other cars run when the AC compressor is running. The easiest way to check is look at the compressor. With the keys in your pocket, pop the bonnet and look for the compressor. Once found make sure the section on the very end of the pulley can be turned freely by hand. This is turning part is the compressor drive plate. Now start the engine with the AC off. The drive plate should be stationary, Don't grab it to check!! Check it visually. The pulley should now be turned by the belt. Now press the AC button and watch the drive plate. If it's as it was before (stationary) then I expect the AC needs filling which will restore the pressure and function. If the drive plate is spinning with the pulley, the compressor is running and so should the fans. If the fans don't run then the performance of the AC will be hugely reduced.

xamtex · Dec 21, 2013

to properly diagnose the a/c you need 2 gauges....1 on the high and 1 on the low pressure ports...with the a/c off both gauges should read around 70psi.
with the a/c switched on the low side pressure should drop to around 35psi and the high side should rise to around 180 psi.
as you only have 1 gauge check the standing pressure on the low side...should about 70psi start the a/c and it should drop to about 35psi.
if you only have 35psi standing then it needs a regas....if the pressure stays about the same when its running then it needs a regas.

Epicuser · Dec 21, 2013

I can't see any fans for my air con, just the electric fans for the cooling system,?

Datatek · Dec 21, 2013

Nodge68 said:
The fans on the Freelander and many other cars run when the AC compressor is running. The easiest way to check is look at the compressor. With the keys in your pocket, pop the bonnet and look for the compressor. Once found make sure the section on the very end of the pulley can be turned freely by hand. This is turning part is the compressor drive plate. Now start the engine with the AC off. The drive plate should be stationary, Don't grab it to check!! Check it visually. The pulley should now be turned by the belt. Now press the AC button and watch the drive plate. If it's as it was before (stationary) then I expect the AC needs filling which will restore the pressure and function. If the drive plate is spinning with the pulley, the compressor is running and so should the fans. If the fans don't run then the performance of the AC will be hugely reduced.

The aircon fans doesn't run on any of my cars unless needed, the switching is based on gas pressure/temperature but I guess the Freelander could be different.

longdog · Dec 21, 2013

Epicuser said:
I can't see any fans for my air con, just the electric fans for the cooling system,?

It uses the same fans.

hd3 · Dec 21, 2013

I have checked the air con pressure and it is reading just short of 35psi

charged ac gas psi depends on ambient temp.
35 psi is good if the ambient temp be 21c
( according to the gauge i have .. 'n that's low-side pressure )

btw: the low-side ac psi be read with the engine running
and ac on 'max' cold .. for 3 minutes ..
i.e. according to the tutorial on this page ( d.i.y. re-charge kit )
http://www.interdynamics-europe.co.uk/

if the psi is too low .. or too high .. in relationship to the ambient temp
then the ac won't operate properly .. i.e. won't cool down the air

some charts online :
Let me google that for you

~~~~~~~~~~~~~~~~~
attached : pic of my gauge ..
inner numbers are ambient temps. in 'F'
outside numbers be psi
( sorry pic is shyte but numbers can be seen )

hd3 · Dec 21, 2013

don't know if those charts help .. or not ..
i.e for an ac test in colder ambient temps

could take a psi low-side reading on mine an report back ( in a few days )
tried my ac today ( i.e. for cooling ) .. be working fine .. brrrrr

( tried it with air-recirculation 'on' )
charged it last summer .. 'n use it daily as a de-mist helper ..

the ac does have a thermostat ..
i think it's to stop the what's-it from 'freezing' ..
but don't quote me

'cause i aint sure ..

~~~~~~~~~~~~~~

have read up on how the ac operates .. still don't understand it completely :-/

xamtex · Dec 21, 2013

there is a temp switch on the evapourator(the bit in the heater box)when the evap freezes it stops the compressor running till it thaws then the comp cuts back in...known as cycling....pretty much like your domestic fridge.

xamtex · Dec 21, 2013

typical gauge readings...will vary a little with ambient temp.

Air con info

freelandie71

Active Member

Epicuser

Ex Freelander Owner

Tiercel

New Member

longdog

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freelandie71

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Datatek

Well-Known Member

Nodge68

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xamtex

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Epicuser

Ex Freelander Owner

Datatek

Well-Known Member

longdog

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hd3

Well-Known Member

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hd3

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xamtex

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xamtex

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