Sudden release of AC Gas in LC 80 (4.5l)

[jarek]

Hello,

Would anybody be able to point me into any direction regarding the repair of my AC system.

It has been throughly cleaned with the condenser removed and washed and some valves/connectors replaced.

However, the problem still persists and the gas is sometimes suddenly released (via valve?) with a big hiss and smell.

This can happen both with a hot or cool engine e.g. after just a minute of driving, both when driving and when idle.

In additon, it did happen once or twice just as I switched the AC on.

The gas has to be topped up after such an incidence.

Any idea what could be the culprit?

Thanks!

 

[Michael Montgomery]

Hi and welcome. I'm no expert but what I have seen and experienced is it can leak from any place. A specialist can put dye into the system to identify the leak / leaks and rectify the issue.

As always the quicker the loss of gas the bigger the issue but easier to find.

Good luck

 

[jarek]

Thank you - they did it but there was no slow leak and this one they said was via release valve (not when they inspecting it of course).

 

[Tractionman]

Hi Jarek
Like M.M. I am no expert, but I would have thought that as the fault has been identified from the release valve, your a/c man would have replaced. Not sure what a release valve is you mention
There is an H high and a L low for pressurising and evacuating the system, and IIRC, they are shraeder valves, as in tyres, so an easy swap when system is empty.
Hang in there,someone will be able to confirm or not.

 

[Chris]

This sounds like a faiure of some sort. There isn't a release valve that magically opens in the event of a problem. Quite the opposite I'd have thought. So it's a faulty component or something. Certainly not a normal function. If you stick something in there it will certainly release. Ask me how I know! It could be that pressure is leaking elsewhere then as it drops there's insufficient to keep the spring in the valve closed? I dunno.

 

[jarek]

I really appreciate these ideas.

I also was told that after each of these events about 25% of gas is out- so I needed a top up. Spent a lot of money this year for monthly top-ups...

I will go back tomorrow and inquire about the shaeder valves you mentioned. The problem is that I live in a rather remote area with few if any specialists.
Not to mention that pretty nobody has a proper diagnostic devices.

 

[frank rabbets]

Sounds like your Schrader valve/s might be at fault. There are 2 on top of the compressor. I would have thought it would be easy to see which one it is but they should have plastic screw tops on them. There is a safety release valve which blows when there is either too much heat but once blown will not hold gas. Obviously important to see exactly where the leak is. There will be oil around that area.

 

[priffe]

Hi Jarek I don't find out how to send PM so I ask here - is there a land cruiser community in Oman?
I am headed there for new years and would like to travel around a bit.
Cheers

 

[StarCruiser]

In many refrigeration systems there are pressure release valves which exhaust to the atmosphere to prevent too much pressure being generated. These are located on the high pressure side of the system and can be a valve or a soldered up plug that melts to release the refrigerant.

The compressor I have on my 80 has the valve shown which I strongly suspect is a pressure release valve.

There’s two reasons it would release gas, faulty valve or doing the job it was designed to do, preventing too much pressure.

A proper refrigeration engineer will be able to fit gauges to the gauge ports (Marked H and L in the pic) and tell if there’s a problem. If the head pressure is normal and the gas is discharged then the valve is faulty and discharging below it’s rated pressure. This is unlikely but possible if damage or corrosion or such like has affected the valve.

Assuming the valve is operating correctly means there is too much refrigerant or a blockage in the system somewhere.

The system operates as a closed loop and relies on refrigerant as gas or liquid being at the correct amounts in both the hot and cold sides and circulating around.

To ensure the correct charge of the correct refrigerant is present, the system needs to be emptied and recharged by weight.
If the system has been opened, or emptied it needs to have a vacuum pump connected to pull out any moisture in the system. Moisture can cause a blockage in the orifice of the expansion valve as it sprays refrigerant into the evaporator in the dash. A good long time on the vac pump will eventually pull such moisture out. You say parts have been replaced, and the condenser removed and washed, could it be that moisture has got in (ends need to be covered to prevent debris or moisture in the air getting in) ?

Like I say, a proper fridge engineer with a set of gauges should be able to diagnose the problem.

I doubt you have any trouble with your Schraeder valves, you would lose refrigerant totally.

If you need to find a good fridge engineer, ask local take aways, restaurants, shops who they use. You’ll soon see the same name come up a few times. He will be busy but most probably worth waiting for.