Van aircon

[phil68]

I had A/C retro-fitted to my Merc Vito about a year ago, made by Eberspacher, on R134A. It was fine for a month or two then when I was sitting in traffic one day there was an almighty sound of escaping gas & a cloud of what I thought was steam (I thought the engine was overheating) -it transpired that it was gas escaping from the A/C in the engine compartment. The guy who fitted it had it back & reckoned it was a dodgy 'O' ring. Two weeks later the same thing happened again. Back it goes. A month later it happens again, only this time about two seconds after starting the engine & it's also accompanied by a GREEN cloud of gas this time as the guy's put leak detection dye in . I had a cursory look & as far as I can see the dye was concentrated around the compressor region. My question is is there a pressure relief valve on these systems as that's just what it sounds like when it lets go -there's an escape of gas & then it stops abruptly & there's just enough gas left in the system to de-fog the screen on winter days. The guy who installed it reckonds there isn't a pressure relief valve & I can't find one.

[alpha]

The last Sprinter I saw with evilspacher gear had pressure valve on compressor cylinder head.

[chillin out]

Hi Phil,

There is a pressure relief on some automotive compressors but not on all.

The garage is probably right in saying its an 'o' ring problem, but it wasn`t a 'dodgy' one. There is special 'o' rings for R134a , R12 ones are not compatable with the oil.


Chillin

[Karl Hofmann]

It is not unusual for manufacturers to install a pressure relief valve in the system, it should look like a aluminium stub around 10mm indiameter and 20mm high, should be hexagonal to allow them to be changed and will have a paper dot over the end. However for these to pop, it should be the absolute last resort, there should be a pressure switch in the discharge side of the circuit which should shut off the compressor if the discharge pressure exceeds around 350-400psi. Have a gander yourself to see where the leak is, there will be loads of PAG lube near where it is though if the leak is so big, I cant see why he needed to use dye. Hope that your man replaces the lost lube when he recharges you.

Just a thought, if your problems occour when you are stationary, are your condenser fans working when the ac is on / when the discharge reaches a set pressure (Typically 200psi) are they working at all?

[slingblade]

Just a thought, if your problems occour when you are stationary, are your condenser fans working when the ac is on / when the discharge reaches a set pressure (Typically 200psi) are they working at all?

Agreed. ive charged a few cars and it is difficult to do so at 70mph. on stationary tick over if the cond. fan does not kick in the system wil blow off. have seen this on 2 x 5 series bmw's. possible fault on fan switch?

[phil68]

Yep, the condenser fan is working, I know that because it's so noisy that I can hear it above the clatter of the engine with the window down There's an electric condenser fan fitted in front of the condenser, even though there's an engine-driven fan behind the rad. My thoughts are with you guys on the condenser fan not cutting in but it's strange that it blew that one time only a couple of seconds after starting the engine

[Karl Hofmann]

Agreed. ive charged a few cars and it is difficult to do so at 70mph. on stationary tick over if the cond. fan does not kick in the system wil blow off. have seen this on 2 x 5 series bmw's. possible fault on fan switch?

The 5 series, bothe the E34 and the E39 suffer from poor quality/ design electric fans, the motors and control modules (later models) are poor beyond belief. I too have come across 5ers that have not shut down on high pressure.

Regarding the Vito it is also worth checking for crud trapped between the condenser and radiator blocking air flow but there could also be a blockage in the system, a damaged drier allowing dessicant block the TXV or swarf from the original installation perhaps

[afeef]

hi all
it is not the problem with pressure relefe valve ,,,
but the problem is :why the gas is out?
ofcorse it is high pressure happining , the cause of high pressure is:
condenser is blocked with dirt,mud,,,,etc
condenser fan is not working properly,that explane what happen to you on trafic light
the thing that mostly happen in car a/c is :
the condenser inside pipes is blocked with dirty oil coming from compressor,
to overcom this :
clean the condenser inside pipes by cleaning solution ,
change the compressor oil
good day