Aircon woes

[pannawonica]

Recently I had a Tx valve fitted under warrenty and the aircon worked better than ever from new. My Puma is 8 months 15 Km old. Yesterday travelling back from Karratha in the heat all it would do is blow warm air . I went outside today and with the vehicle under the carport ran the aircon checking the temperature output with an accurate probe. The system quickly and consistantly pulled down to around 5 deg centigrade. As Pauline would say " Please explain ? " To me aircon is a bit of a dark art.

[PAT303]

You don't have a set of bad arse cook a roo at 100 yards set of spotties on the front do you?. Pat

[pannawonica]

Err actually yes, Lightforce Genesis HID bin wondering about them, however it never had any effect on my TD5 Disco or the V8 Disco.

[Davehoos]

nothing like spot lights and roo bars at hyway speeds to overheat the system.
the answer is to make the air pressure in the engine bay low enough to draw the air through.

what caused the TX replacement.is the compressor a variable capacity pump.

did it freze up or was the condensor over pressure.what other bits should have been replaced.the gas quantity is critical as the temp rises-you find the car will go all year over gassed untill a hot day and no room for the liquid.

any crap in the system collected in the dryer lowers the liquid line pressure and tells the TX not to work as hard.if it freezes up the pump stop working.

these green sytems always work when tested-but not when tested.

dark art-----correct.they cant teach vibe.
there is no way to make green air conditioning with undersized condensor work,they need a small liquid line coole[calling this subcooler] or my favorite an accumilator and a liquid catch tank.

[pannawonica]

Yes I think you have made a couple of good points. From my understanding the dryer is also a filter and a pressure differential affecting the TX valve. Regarding the Roo bar I have an ARB and an insect screen, however I have a big arsed standard ducted fan drawing the air through. The Tojos at work all run spotties and bar work , like my Puma and seem to work OK. However I would consider upgraded parts or additional installations required. Her indoors would like to improve the aircon no argument there. Do not understand vibe, but your advice of bigger condenser make good sense just like a upgraded intercooler.It is my belief that the system did not freeze up and that it was under powered. Weeks earlier when the weather was cooler it worked just fine , which would support what you have advised.

[pannawonica]

What I neglected to say that from new it had been low on gas as advised by dealer, yes I know. They topped it up twice til I spit the dummy. They eventually admitted a faulty TX. However I cannot be sure.

[P38ace]

In replacing the TX valve they did not necessarily fix the initial problem. As well as the Tx valve I'm told there is also a temperature sensor, which I had replaced under warranty 3 times before they got a "special, tested, guaranteed to work one" from LR UK.

Also check under the bonnet that your heater valve is actually closing fully. That's another long story.

[Davehoos]

dealers often replace TX valves out of frustration.im guessing it has a electronic controlled variable capacity pump.

TX controlls the flow of liquid by restricting the liquid line creating vapour.when the vapour temp drops bellow the preset temp most open up and dump liquid into the evaporator basically defrosting it.other brands TX block off the flow untill the temp returns to the presset.
if the low side pressure is bellow normal the pistons dont stroke as much and the high pressure reading drops-so the checker say it low on gas.

with these new systems your sopossed to use laser temp guns.when i have i found blocked condencors.the heat change was so high that when water was sprayed on it dryed in spots.

have done dozens of degas/regas to allow them to remove the insides.
often it was the insides of the european hoses had colapsed or was leaking through the very thin alloy pipes.

dryers are not covered normally by warranty as it a service item-but it should be replaced every time.the new sub cooler condencors most you can replace the desicant and give it a quick clean but realy the should be replaced as a job lot.

Teaching VIBE.
it easy to teach someone the look at a pressure chart and a diognostics chart.trust me that often doesnt get these to work.
most of the time you can diognose troublesome cars parked in the driveway by have a friendly chat..you discard most of what they have been previously told-my old boss luved to connect gauges to the vehicle and remove the grill..this had more to do with showing you know how to get the bonnet up.

[Davehoos]

however I have a big arsed standard ducted fan drawing the air through

original?can you here it working when warm?

insect screens-often have to be removed for hyway work.have been fitting shade cloth over the bumper allowing air to come around behind.

nissn patrol had issues around 110kmh at 120 they cooled.some had different numbers of fans some had none with some running on pressure and some temperature.it was an air flow issue with air going over the cab and not through the radiator.

[pannawonica]

The viscous fan is working well moving large volume of warm air. The insect screen ARB type has 5mm by 4 mm holes. My previous Disco TD5 had the shade cloth on the roo bar type and worked fine. The dealer use an outside contractor for aircon and may not be as up todate as yourself Davehoos.
However do you think its worth testing minus screen? I am a little reluctant to remove spotlights due to the fact I drive down to Perth usually at night. Thanks John.