A/C mystery coolant leak

Harshan · Post by **Harshan** » Tue Jun 12, 2007 9:39 am

Hi all,

I happened to install a new a/c cooler in last april. Simply because when I buy the vehicle the cooler was gone and there were no coolant left in the system. Simply replaced the cooler and the evaporator and re-gassed (charged the refrigerant ) and everything went fine for abt 2 weeks and it stopped cooling. Brought it to the a/c guy and he re-gassed and again everything went fine upto 2 weeks and stopped cooling. took it back to him on sunday and he checked entire system, compressor, condensor and tubes for leakages apparently there aren't any leaks.. he pressured the system with nitrogen dry nitrogen and left it for a day ... and pressure remained well until he re-gassed it on yesterday evening .. fine the a/c blew fine.. and drove 10kms home in the night.. no a/c needed once in a while switched on the a/c..
to my utter surprise today morning a/c didn't blow cool at all.. compressor engages, evaporator emits the whistle blowing kind a sound meaning that no enough refrigerant in the system.. my worry is how to find this mystery refrigerant leak? something start leaks when the system runs.. not the compressor .. checked under water for leaks.. any thoughts will really helpful .. any over pressure valve ?

Post by **Welly** » Tue Jun 12, 2007 9:55 am

I seem to remember my a/c guy telling me that on many french a/c condensers they can leak where the drier is fitted at the end of the condenser.

The drier is basically a dessicant bag in a tube and I think there can be a leak from the screw thread that secrues the drier lid.

Have you inspected all the joints etc under UV light (if you have dye in the system the UV will show the leak).

Harshan · Post by **Harshan** » Tue Jun 12, 2007 10:05 am

many thanks to the thought.. i'll check this ... and i dont think my a/c guy checked with UV light.. what he did was pressured the system with dry nitrogen and kept it for 8 hrs... the pressure remained ... no decrease of the pressure..

Post by **Welly** » Tue Jun 12, 2007 10:11 am

To be honest it depends on how much pressure you apply to the test.

Some people test to as high as 250psi, you won't detect a leak so easily at lower pressures like 100psi.

On a hot day the cars own a/c pressure will go above 100psi itself.

Normally the UV test will show the problem.

Harshan · Post by **Harshan** » Tue Jun 12, 2007 10:25 am

Just phoned him ... he said tested in 250psi and he said the on a hot day with some rev on the engine it'll go up to 280psi..

Harshan · Post by **Harshan** » Fri Jun 15, 2007 11:54 am

Hi all,

i got great news for you'll... that is I've fixed the a/c system leak.. brought to the a/c guy and pressured with dry nitrogen at 260psi and left ... no leak no pressure drop ... and I checked the a/c gas recharge valve and found that it has devised a huge leak. tighten the valve and now there's no leak and a/c blows icey cool air ;))

thanks you all guys for the useful tips and for the time spent on replies ..

Post by **Welly** » Fri Jun 15, 2007 12:43 pm

Well done - and it's good that it was only a simple problem too.

Although I suppose you have spent money recharging it all twice

dervpower · Post by **dervpower** » Fri Jun 15, 2007 5:01 pm

why do you need a drier??

Harshan · Post by **Harshan** » Tue Jun 19, 2007 4:29 am

Welton wrote:Well done - and it's good that it was only a simple problem too.

Although I suppose you have spent money recharging it all twice

well thats what I thought.. but he charged only for once.. coz the second recharge was due to his fault anyway ;)