Jump to content
LegacyGT.com

2006 5MT LTD AC compressor compatibility?


Recommended Posts

A sad followup to this thread, one year later, now that it's hot again: after running the AC for a couple of weeks, it's low on refrigerant again. Took it back to the shop from last summer, and they found no dye anywhere. Their best guess is an internal leak in the compressor. That diagnosis makes sense to me; it only seems to leak when it's actually running.

 

 

 

However, $1500 for a new compressor and dryer/condensor is a bit rich for an aging car. I'd rather swap in a used compressor and see if it holds pressure with a nitrogen charge for a couple of weeks, then put (another) dryer/condensor in and recharge .

 

 

 

Is there a general way to research parts compatibility between vehicles? I have an 06 LTD 5MT -- I'm finding lots of Canadian used ones from ATs, non-GTs, and non-LTDs... but the cheap ones generally aren't a precise match.

Link to comment
Share on other sites

Internal leak in the compressor?

 

 

Sure, it could be leaking past the piston seals into the crankcase. Then the dye would end up in the crankcase oil.

 

 

The technician noted in the original diagnostic that the high-side pressure was on the low side -- that could be symptomatic of the same issue.

Link to comment
Share on other sites

First, keep in mind that Subaru compressors, at least the 2005 Legacy compressors I've disassembled, do not have pistons. They are scroll compressors. That difference is immaterial to the discussion, however. In any type of compressor, there will be blow-by from the compression chamber to the non-compressing volumes (e.g. crankcase). That volume will be full of refrigerant, oil, and in this case presumably dye. The theory being proposed here is that the seals between that volume and the outside air will pass refrigerant but not dye. I find that suspect. Furthermore, it proposes that the refrigerant (sans dye) will escape from the non-compressed volume rather than from the compressed volume. I find that considerably more suspect.

The strongest point of that theory is the possibility that the seals of the non-compressed volume were designed with lower pressure in mind, and that blow-by far higher than designed/expected is overwhelming those seals. But I see nothing in that scenario to suggest that the dye would be stopped by those seals.

If the dye is definitely not escaping from the areas that are easily visible (the engine bay), I would strongly consider the possibility that refrigerant is escaping in an area that is not easily visible - in the HVAC box inside the dash, just before the expansion valve. That's where the last slow refrigerant leak I had to deal with was.

Link to comment
Share on other sites

I hate to link to youtube, but I just thought of this video that I remember watching some time ago. The source of the leak in this case was the evap core, and the leak was sensed through the evap tube I think that's the same thing that relative said, but ac systems aren't my strong suit by any means. Seems like you'd need one of those handheld refrigerant detectors to sense that though.

 

Personally before spending that kind of money, or replacing the compressor in general, I'd really want to know that would 100% fix it.

 

Link to comment
Share on other sites

I spoke to the shop. They in fact did *not* visually inspect the evaporator box for dye, but they did run the system with a sniffer jammed into it, with no results. This is an evaporator coil that I replaced last summer, chasing this exact same issue, so I'm inclined to believe that their hunch is correct.

 

 

 

I'll take down the dash again and at least inspect the push fittings for dye, before replacing the compressor, though.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.



×
×
  • Create New...

Important Information

Terms of Use