I need vr aircon info

[jimmer79]

I need some information on my aircon system, I've fitted a new condenser and dryer and new pipe from dryer upto bulkhead and I've had it re-gassed it kinda worked for maybe a month but then it started to gradually blow warm air I have now fixed the warm air problem by replacing the heater tap and it now blows cold air but if I turn the aircon on it doesn't get any colder than normal cold air from the blower, the compressor is switching on and off and there is still gas in there but it's just not cold, is there anything else I can check myself

[Burnout124]

the tx valve could be playing up or maybe a blocked evaporator the best way to find out what is rong is by seeing what your pressuers are .

[hako]

Is one of the pipes going thru the bulkhead colder than the other when the compressor is engaged?....you may need to peel the cover off the wiper arms under the bonnet to check this.

[jimmer79]

Ive checked the pipes and they are the same temperature they aint hot or cold just normal

[hako]

One should be colder than the other. You may need to get it looked at as it seems you have no gas left or it's below the minimum pressure. Winter is just around the corner!

[VN SV5000]

yea it could be the tx or evap but possibly leaking still in the system, remember only a little of refridgerant like 50 grams can trigger the compressor, but be careful when running the system as running it without gas/refridgerant can cause the internals to break down and spread, which mean dash out job!

[Z2TT]

One thing I picked up on your post, compressor cycling. How often does the compressor cycle on and off?
If so, Short cycling (Compressor turning off and on repeatedly) is caused by things such as

- Blockage in the System, such as blocked TXV (But not necessarily)
- Low gas charge

Now in the case of a blockage e.g TXV, the low pressure side would go into vacuum very quickly and a knowledgeable a/c service person will be able to know if this is the case.

Low gas charge, if the gas had leaked out very quickly, and being a VR I would not be surprised, you can thank Holdens engineers for this one, look around the front bumper for leaks around the a/c lines, especially where one a/c line takes a turn near the chassis on the passengers side of the front bumper

Pitty your not in Perth I could have taken a look at this for you but keep the advice in mind.

[jimmer79]

But surely if the gas had leaked out I would be seeing green dye somewhere cos they put it in with the gas?.
And when I said the compressor switches on and off I meant with the switch it actually stays on once switched on and doesn't turn off until switched off, sorry I can see I should have explained that a bit clearer.

[Z2TT]

You would yes, if the leak spot is visible to the eye.

Ok so basically it is not cooling, it may be a faulty expansion valve not regulating refrigerant flow and this is pretty much a dash-out job,
then again there could be other causes so it has to be diagnosed properly by somebody who knows what they are doing.

Does the cooling fan come on in the engine bay when you turn the A/C on?

[hako]

I thought they used ultraviolet fluorescing dye in A/C systems and you then needed a UV lamp to view it....but maybe times have changed. If the compressor is actually engaging and the engine revs drop slightly when first engaged then there is gas in the system....if it's not engaging then there is probably nil or little gas.

[wamboin23]

uv dye is kind of visible, easier with uv light though.

and commodore tx valves are easy, just under the panel beneath the wipers, two bolts and it's out.

[jimmer79]

Yeah the cooling fan runs constantly well when the cars sat still anyways, I'm pretty sure you can see the dye cos while they wer gassing it it blew a pipe and the whole front of my car turned green it was every where, I'm so over this ute seriously I liked it now I want it gone, the problem I have is knowing where to take it to get work done cos I'm English an I've only been here a year back hone I have contacts anno where to go an who is trustworthy over here I'm still to find all this out, I'm pretty mechanicallyminded so would rather tackle stuff myself, so where is this valve right behind the dash

[jimmer79]

So what does the tx valve actually do, I no summers over but problems eat away at me an I can't rest until they are solved I'm a bit strange like that I can't just leave stuff alone

[Brett_jjj]

Id just take it to a couple of different A/C repair places, and get them to find the problem and to give you a quote for fixing it.You can either get the cheaper place to fix it,or you can post up the problem theyve found on here and someone here may be able to help you fix it yourself.Even though summers over,I find the A/C is excellent to use on rainy days,I turn the A/C on with the heater on hot,with the outlet set to demist,this will demist fogged up interior glass in a few seconds.It does this so well because the A/C system also dries the air as well as cooling it.

[jimmer79]

Yeah true it does come in handy other than just in summer, yeah il take it to a couple an get a quote but il def try an fix it myself I wanna get rid of it now but I'd rather it was working before I sold it I don't like selling stuff that doesn't work

[Brett_jjj]

Once you find out what the problem is,you could probably fix it yourself, with some help from here if necessary,and then you just have to get it regassed,I just fitted another compressor to my VS a few months ago,I fitted it myself,then just took it to get it regassed.I bet the A/C place would have wanted a small fortune if they had fitted the compressor as well.The regas cost me $120 including new compressor oil.

[Z2TT]

Hi,

The UV Dye when it leaks in small amounts, you need to use a UV Light to see it, but when it leaks in large amounts, it will be visible and green
in colour when the oil leaks from a leak spot.

To understand what the thermal expansion valve does, read about how a basic refrigeration system works, because really that is what the cars A/C System is.
To put it in a nutshell. Basically in order to get cooling, refrigerant needs to turn from a liquid into gas, get a deoderant bottle, all liquid inside, spray it on your hand and notice how cool it gets? That is because of the state change from gas to liquid.

In the refrigeration system that is what happens, the compressor compresses the gas, and in the condenser stage (at the front bumper area), it gets cooled by airflow and it condenses (becomes a liquid), This liquid resides in the receiver/drier and liquid line, you can call this the "waiting room". The Thermal Expansion Valve meters the correct amount of liquid into the evaporator.

Once the liquid goes inside the evaporator (inside dash), this is where it boils off, and turns from liquid to gas, making the evaporator colder. Your TYPICAL expansion valve has a bulb on it that attaches to the low side pipe (larger a/c pipe near firewall), and monitors the temperature. The bulb is filled with a gas, and this gas helps modulate the TXV by pulling or pushing on a TXV, so if the low side line is warm, the TXV opens up more, and meters more liquid into the evaporator, if the low side line is cold enough, the TXV meters less liquid in.

When a TXV valve is blocked with debris or shut closed for whatever reason, it will not be able to meter the correct amount of liquid inside, so not enough evaporation and cooling can happen. If the TXV is not modulating (Stuck Wide Open), it will meter too much liquid, and as a result not enough evaporation can occur as the evaporator is flooded full of liquid.

Proper operation of the TXV will decrease over time, so on second hand cars, especially our nearing 20 year old VR/VS's, a new TXV is a good investment. If your hell bent on getting your A/C working as best as possible, new TXV, New Compressor, New Condenser, and New Reciever/Drier (Mandatory).

[jimmer79]

wow you really no your aircon, ive replaced the condensor and dryer so i guess il go for tvx valve an maybe compressor cheers for all your help guys il keep you posted as to what i find