I noticed a week or so ago, that when I stepped out of my truck with the engine running, I could hear a distinct clatter coming from the area of the A/C compressor. I turned of the A/C,.......and sure enough, the clatter stopped as well, compressor back on, and the clatter began again. I have 240,000 miles on the truck, (runs great) and the A/C is icecold. Its still the original compressor,....hate to tear it apart with it still cooling, but, on the other hand, I dont want the compressor to disintegrate and fill the system with debris.

Any thoughts on this?

Brian in Austin

If the system has been leaking and you've just been topping it up without adding oil then maybe it just needs oil.

No, I have never needed to top it up.

Try adding some oil, then.

John B.

Is it possible to be low on oil on a system that has never been opened and has always functioned fine (and, other than the clatter, still is)

How do I add oil to a sealed operating system,....and,...how much would I add?

Brian

There are injection tools (I have one) that would keep the system sealed, otherwise you'd have to evacuate, add just oil and recharge, or oil with refrigerant. Adding oil to a system that has remained closed is a guessing game on how much to add. Too much, as you may know, will reduce the efficiency.

Maybe the shaft bearing/sleeve is worn?? Try removing the drive belt and pull/push/shack the pulley to see if it has excessive play. You may need to lock the clutch with 12v jumper.

Here's a site where parts may be available:
http://www.acsource.com/index.aspx

I've dealt with them and they are very reputable.

The belt pulley has a bearing seperate from the compressor internal bearings, which may rattle only under load/clutch engaged...

Are you referring to the tensioner pulley or the pulley on the front of the compressor?

On the compressor. IIRC, the pulley has it's own bearing, independent of the compressor shaft bearing. I've had them go bad in the past. You can generally hear it with a mechanics stethoscope, a lighter rattle than with the compressor engaged..