So, I've had my car for a bit over a year and I've been having a persistent problem - something under the hood squeaks incessantly. My dad said it's the AC Compressor bearing since it usually comes up when the AC button is depressed. However, it has sounded even without the AC button depressed, usually when I have the front defrost/ground heater as well as the rear defrost. But here are things I've done to the car, or symptoms I believe are related to the problem:
-When I originally got the car (January 2013), it wasn't making the noise at all. But the noise began showing up around May-June.

-Doesn't affect the actual AC/Heater or the performance of the car at all when the noise sounds. The cars till blows ice cold and the defroster/heater both still work flawlessly.

-The noise sounds not only when I start the car cold, but from a stop when the climate outside is cold.

-The squeaking sometimes sounds even when the AC/Heater are not on.

-In general: the headlights and interior lights dim when I roll up the windows.

-Warming up the car for a good 5 minutes SOMETIMES helps reduce the squeaking for that commute.

-Left marker light is out. Still signals, but when I turn on the headlights, the left marker does not come on. (tried replacing the bulb and assembly - still out)

-Original Alternator

-Replaced the Alternator and Power Steering belts soon after I received the car.

-Tried belt dressing and silicone lube a couple times, and the problem went away for a couple hours, then the squeaking resumed.

-129,xxx miles

-Everything is OEM, to my knowledge, except the oxygen sensor (needed to pass smog last year).

What problem(s) do you think are causing this? Is it worth it to fix it? If so, what is an estimate for the job/parts? Any advice or thoughts would be appreciated!

 

Suggest not using belt dressing or lube. This is a temp fix at best and some find it does more damage then it is supposed to cure.

Belt squeal (slipping) causes glazing which can damage the belt. The result can be more even squealing over time.

The AC pulley is always rotating when the engine is on. When the AC compressor shaft is not rotating, (pulley clutch disengaged), the pulley is spinning on the compressor shift via the bearing. When the clutch is engaged, the pulley is locked to the compressor shift and the bearing is not working.

The compressor needs torque (HP) to rotate. When the clutch is engaged, the belt transmits this power to the compressor shaft. If the belt does not have enough tension, is damaged, glazed, wet or worn out, it will slip when the compressor engages (clutch is engaged).

Warming the engine up may also warm up and flex the belt allowing it to engage the compressor pulley better when the clutch engages.

The usual solution to belt squeal to replace the belt with new. In the process make sure all pulleys are clean of oil and other debris. Then adjust the belt tension to the correct amount.

There are gauges to adjust tension but most people just guess based on experience by pushing midway on the belt between pulleys.

Too tight of belt is also bad as it places excess load on the bearings causing premature failure. If you don't have a gauge, you want tension just high enough to keep the belt from squealing when the AC is working.

If not doing so, to save money buy name brand aftermarket belts such as Gates, Goodyear, Dayco, etc.

On headlights. Do they dim at engine idle and 2000 rpm?

On the signal, the light bulb doesn't work then what signals? The dash signal marker?

Are you doing the work yourself? A belt change is easy enough. A belt should cost $7-15 depending on where you buy it. Buy a Haynes service manual for the car (around $20) and search the internet for detailed info changing the belt. YouTube may even have videos.

When buying a belt, make sure you get the one called, alternator belt WITH A/C, for your year of car and engine type. 4-cylinder (5SFE).

 

I agree with Joey. Be sure to spin each pulley with the belt off to make sure it turns freely and does not bind or turn hard. Also, with the engine running, pop the hood and listen to where the sound is coming from. You can use a piece of fuel line and hold one end to your ear and the other end you move around the pulleys like a stethoscope.

 

I'll definitely check out the belt and the bearing as soon as I can.

The headlights dim if I pull the switch to roll up/down the windows, regardless of if I'm idling or driving.

For the signal, the dash light displays, and so does the outside light but the marker light that comes on with the headlights: http://carphotos.cardomain.com/ride_..._large.jpg?v=0
(I know this isn't OEM, but the two orange lights on the side - for me, one of them doesn't come on, but it still signals.)

The two belts that have been replaced (alternator/power steering), I have done myself.

 

This car have turn signals on lower front area of front bumper?

 

No, it's the ones above the bumper, right under the hood. They're two-harness lights: one for the marker lights that come on with the headlights and one for the turn signal. The marker light doesn't come on. I've attached a picture of what happens. Hopefully it'll clear up the confusion. As you can see, one of the marker lights is on, but the other doesn't come on. However, both of the signals work perfectly fine

 

Remove the harness wire plug to the turn signal bulb (as done when changing bulb).

Examine the electrical terminals in the socket for corrosion or other problems.

Use a voltmeter determine if the blinker 12v power electrical terminal has 12v when blinker is working.

Blinker wire is Green/Black.

Use an ohm to determine if the ground wire terminal has a good electrical connection to chassis. Resistance should be 0 ohms. Wire is White/Black.

The running light 12v power wire color is Green/Orange. Ground White/Black.