My AC is making noises. A mechanic said I should replace the expansion valve and AC dryer along with the AC compressor? I've been reading replacing AC compressor should be enough. From what I read, I should only replace the expansion valve and AC dryer if there is a complete failure. At the moment, my AC compressor is work but just making noise for a second when it kicks on.

Any ideas?

 

It's generally good to replace the filter/drier when opening the AC.

 

What are the expansion valve?

 

The expansion valve is what meters the amount of refrigerant going between the high and low side. Here's some more information about how it works: https://en.wikipedia.org/wiki/Thermal_expansion_valve

If it's in the same place as the 98-00 trucks, it's mounted on the firewall.

 

I actually mistyped. I meant to say, what about the expansion valve? Does it need to be replaced? Or, does the compressor and dryer alone need to be?

 

If the compressor didn't throw metal through the system (like when they fail) it's probably ok. When I tried to replace mine a couple years ago one of the bolts seized (steel bolt into aluminum) and broke off, so I had to machine a new "nut" as well as the new expansion valve to hold it down.