Thread: On/Off Air con compresser

I've heard that using fresh on dusty roads slightly "pressurises" the cabin and hence prevents the ingress of dust?

I've got the pre-update AC system so I just use whatever is cold I'm presuming its recirculated

You are correct it will pressurise the cabin and stop dust coming in from leaks in doors/windows etc., - however the air you drag in through your ac will also contain dust, channelled into a smallish pipe then it dumps on your evaporator coil, blocks an air filter if you have one.

The dust mixed with the water on the moist coil will cause a mud, block your condensate drain - and in the long term lead to corrosion of the evaporator, or if the cooling coil is very blocked this will reduce/stop air flow the coil will freeze - and split. Some later Discos have a frost sensor - but again if that is covered in dust or mud from the mix of dust and water there effectiveness is reduced,

The blocked condensate drain is a nusience - you end up with wet feet and a soggy carpet - a pain in the bum but easy to dry out and unblock the drain whilst fiddly can be done from under the car. However a corroded or bunged up evaporator is a real pain to repair - just to remove it on most Discos means half the dash has to come out, being ally they don't repair well - and generally will have to be replaced.

When you are running without ac - and to some degree with the heater on I would put fresh on to pressurise as heater cores seldom are 'moist' unless you have a leak in it or have been through some pretty deep water, and any dust there can normally be removed with a blast from an air line.

This may help with diagnosis.

Ladas

Originally Posted by ladas

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.

Thanks for that bud....I will try the test but not at the mo......its 38 and blowing a gale, will wait until tommrow .

I rung our local Air con man, he can "Have a look" on Monday.....Normal cost is $140 if gas is needed inc time etc...but he said if no gas needed will be much less than that....so for $100 might be worth it for piece of mind if nothing else . He also said they just do a leak test and a look over, so doing a kind of a service I guess??

Yes - might be the easy way to go. $100 - $140 for piece of mind well worth it.

Shame you are not closer - it would only cost you a slab of VB

ok thanks guys...I did a little test.

Disco inside temp 30 dec

Fan on setting 1

On recirculate

At idle took 1min 45sec to get down to 12 dec, compresser cut out at that time. So all up it ran for about 2min and stayed at around 10-12dec, (but I guess I should have run it much longer to see how low it would go)

compresser fired back up again in around 20 sec (forgot to time it) and if I let it go Im sure it would have got much lower in temp.

Also the lines out of compresser top one was fairly cold and the bottom one was very hot, unable to hold for anymore than 2 seconds

Im no expert but maybe our air con is fine after all, just expecting to much from it ??

What do you think?

Originally Posted by amshaw

ok thanks guys...I did a little test.

Disco inside temp 30 dec

Fan on setting 1

On recirculate

At idle took 1min 45sec to get down to 12 dec, compresser cut out at that time. So all up it ran for about 2min and stayed at around 10-12dec, (but I guess I should have run it much longer to see how low it would go)

compresser fired back up again in around 20 sec (forgot to time it) and if I let it go Im sure it would have got much lower in temp.

Also the lines out of compresser top one was fairly cold and the bottom one was very hot, unable to hold for anymore than 2 seconds

Im no expert but maybe our air con is fine after all, just expecting to much from it ??

What do you think?

I think it's just fine - run it on 2 most of the time - it will feel better (purely placebo)

The readings and the 'feel' sounds about spot on for R134a - I think it's running as well as it can.

Originally Posted by ladas

I think it's just fine - run it on 2 most of the time - it will feel better (purely placebo)

The readings and the 'feel' sounds about spot on for R134a - I think it's running as well as it can.

Ok thankyou for your help, if your happy I will ring and cancelle my time with the air con DR, which wont be a prob as I said I may do that as i had to do some homework on the Disco's air con