1999 Chevrolet Malibu Clicking noise

What you're describing is typical of a binding upper strut mount. Reach over the top of the tire and wrap your fingertips around part of the coil spring, then have a helper slowly turn the steering wheel. You should feel the spring rotate smoothly with the wheel and tire. If the upper mount is binding you'll feel the spring wind up then suddenly pop free and turn.

There are other ways for the upper mounts to become worn or defective but it can be impossible to tell until the struts are disassembled to be replaced. That's when a visual inspection shows new mounts are needed and the mechanic has to tell you more parts are needed than first thought.

First, did you feel the binding coil spring when a helper turned the steering wheel? Next, I reread your first post and I see that I focused on "All this is done while the car is at rest". Now I see you also said, "under load while turning to the left". By "under load", do you mean accelerating or the car's weight is on the tires? If the clicking occurs when the car starts moving, that would almost always be a worn outer cv joint. They CAN make a clicking noise when the car is standing still but that would not occur often or every time you turned the steering wheel, and if you did hear that, you would surely hear it when the car started moving.

If the car has to be moving to hear the noise, there is a tool you might be able to borrow or rent from an auto parts store that borrows them called the "Chassis Ear". It is a set of six microphones, a switch box, and headphones. You clip the microphones to suspect points, then drive around while listening with the headphones. You can move the microphones around to zero in on the source of the noise. Be aware that many mechanics have never seen or even heard of this tool. Suspension and alignment mechanics use it to find rattles, squeaks, and other noises.

The original version of this tool had six wired microphones. There's a newer version that has four wireless mics and two still with wires. If you can find that model, you can attach a wireless mic to the left half shaft with a velcro band that comes with the kit. If the cv joint is making the noise you will really hear it with that tool.

You mean to tell me the noise is there with the engine not running and the car isn't moving; just turning the steering wheel? That can't be cv joints then either. If you can't isolate the cause by listening and feeling under the car while a helper turns the steering wheel, have the steering and suspension systems inspected at a tire and alignment shop. They're experienced at finding elusive noises. I'd like to suggest the cause is not serious, but we don't want to risk a broken ball joint or something else almost as dangerous.