I live in a small islands country with no Volvo dealer. The car is a Japanese export imported here.

An air con issue has developed. The local guys have run out of ideas.
The air con pressure is good, no apparent leaks, but the cooling is almost non existent. It used to be powerful.

Symptoms, the pipe circled in the attachment in red (at the back of the engine bay just in front of the wipers) freezes when the air con is running. It shouldn't and the local guy says that usually he would diagnose a TX valve near the evaporator, but I gather the 850 aircon doesn't have a Tx valve there.

He is now suggesting it might be the "orifice tube" which i gather is located down near the gas inlet valve, by the power steering fluid tank front right of engine bay looking forwards (RHD car)

Air con pipe that freezes (frost) when running - air con is not cooling effectively


Would appreciate any tips from someone who knows! What part do i need to buy when i go to UK next month?

Thanks


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Yes your AC system uses an orifice tube, and if clogged or partially clogged will affect cooling performance. (but what clogged it ?) They are a generic part - (used in many brands of cars) and should be able to find them at auto parts stores. I trust you have evacuated (removed existing gasses and pulled a vacuum) on the system and installed the correct volume of r 134 (1.0kg?) Freezing up near the orifice tube could be because the system is low on refrigerant or there is moisture in the system due to poor charging techniques. (sometime in the past 25 years)

https://www.fcpeuro.com/products/vol...tube-3545086oe

 

Hi Hoonk - fantastic advice, thank you so much! This means all I need is to get the orifice tube. To be clear, is the orifice tube fitted inside that small pipe that gets frosted up (my photo) and that is the same part no. 16 in the diagram?

Thanks again, really helpful!

 

I still would try an evacuate and recharge first before taking anything apart to make positively sure the system is properly charged and it's not simply moisture freezing up in the tube blocking refrigerant flow. (moisture get into the system through poor charging techniques used during the past 25 years, DIYers self adding refrigerant is one way to contaminate the system!)

If you are taking it apart, you might want to make sure that fitting will come loose first, aluminum fittings like that tend to seize after x years. Once you get it apart sometimes the tubes are very difficult to pull out in one piece. You'll need an oring (#18) or it's a generic size also. There is another oring on the orifice tube (#17) but those usually come preinstalled on the new tube.

 

Thanks will do! Have a nice day!