1993 4runner. 3.4 swap from a 2003 Tacoma. Did this swap probably 12-13 years ago and never got the a/c going.Trying to now. Have the electrical sorted I believe.

Question. I pulled the 3.4 compressor that I had installed years ago with the 3.o manifold and realized there was this gaping, threaded hole on the back side of the compressor. What is the purpose of this and what do I do with it?

A/C is new to me, figuring it out through old threads and posts. Couldn't find much on it today. First pictures are my compressor, last one is reference pic. In my pics I realize there is a broken off allen in the bolt head. Cheap HF, cost me a few hours this afternoon.

 

On mine https://www.yotatech.com/forums/f116...-r134a-284801/ , the extension housing has the two ports to attach gauges. I don't see any ports on your extension housing, so I would guess your tapped hole is for such a port. I can't explain why you have only one.

 

If it's the gauge ports I think you are talking about I have those on the lines up close to the firewall.

I'm wondering if it's for some sensor like a high pressure one?

 

As do I.

You'll notice that in your reference photo, and in the photo of my extension housing, there is a fitting with a hex-head on the high-side. This isn't a sensor. My best guess is that it is a check valve, an unloader, or perhaps an over-pressure relief.

If you look at the drawings of the compressors for a 2003 Tacoma http://parts.lakelandtoyota.com/show...rimLevel=18360 , you can see that the one that matches yours shows the additional piece, but not with a separate part number. Meaning; it's not supposed to be removed. To replace it, you might be able to get the whole extension housing. DO note that the drawings show the compressor in your photos as coming from a 2.7L 4wd Tacoma.

 

Oh man, I wonder if the junkyard sent me the wrong compressor years ago. But I thought I had swapped that manifold piece over onto the 3.4 compressor from a 3.0. It's been a while.

Thanks for the help. I'll look into my options.