My AC is working intermittently, best under acceleration, horrible in stop & go traffic. The dealership told me I need a new compressor clutch but the written estimate was to replace the whole compressor assembly. Replacing just the clutch isn't too bad, is it? I'm pretty handy and do a lot of my own work but I typically avoid the AC system. Replacing just the clutch doesn't involve draining the coolant or anything, right?

 

Your symptoms don't sound consistent with a bad compressor clutch. Under acceleration (assuming you mean somewhat hard acceleration) the clutch will struggle more to engage if it's worn that at engine idle. How well does the A/C work on the highway at a rather constant speed? Does the compressor cycle frequently? Did the dealership check the pressures for the high and low sides? What year is your Explorer, and is it under warranty?

Replacing just the clutch and field coil isn't necessarily that difficult, but if that doesn't fix it and you end up needing a new compressor it will not necessarily be cost effective either. Proper diagnosis is the better option. Replacing the clutch and field coil would not likely require "draining the coolant" or even evacuating the refrigerant, but that might depend on the model year of your truck.

If you are planning to do the work yourself you might be better off to get a second opinion. However, you should consider being up-front with the place providing the second opinion that you want to pay them for a high-fidelity estimate as you plan to do the work but do not have all the right tools and skills to properly diagnose. And let them know that if the diagnosis is for something you feel comfortable replacing, you would pay the shop to evacuate the A/C system, then you would take the truck to perform the repair, then bring it back to have a vacuum pulled, a recharge performed, and final leak check. Paying for those services would be less expensive than buying the tools to do that work correctly.

-Rod