Receiver-Drier view glass/'91 legacy AC

[saw]

I've been having an intermittent AC problem. When it works, it cools well. The problem is getting it to turn on and then keeping it on. May work for 20 mins. or 5secs and then kick off.

When I look through the receiver-drier view window with the AC on, liquid shoots by, pauses briefly, then shoots by again. It's not a continuous stream. Does this sound like a typical freon flow through one of these systems?

The mechanic that looked at it pooh poohed this as the cause for the AC's sporadic nature and said the problem was electrical in nature.

[Legacy777]

The stream should be constant. It sounds like the compressor is shutting off, or something plugged (which is less likely IMO)

[St Nickolas]

A/c problems are no fun. Do you have the (complex) electrical diagram? Lots of possibilities. Do a search for some old posts on the subject. Seems that the thermal switch attached to the evaporator (I forget the name of it) that shuts the system off when the evap reaches 32F is a common problem (I've bypassed this switch on both my Legacys).

 

Does the compressor clutch shut down or does a blockage trigger the system to shut it down? The most common blockage would be water in the system that ices the expansion valve.

 

Nick

[nipper]

The first possability is that the system is low. Cant really tell anything untill gauges are on the system and make sure the pressures are correct. Pressures will also tell us if something is clogged or if moisture got in the system.

 

 

nipper

[NorthWet]

You should not be able to see the freon stream, as it will appear as a clear liquid. If you see a white froth, this is not the proper state for the freeon to be at for this point in the system. (Though, even in a properly charged system you still may seem some froth/bubbles.)