Since I'm not familiar with your car I can't tell you whether there's an automatic tensioner or not. But one thing I can tell you for sure is to fully diagnose the problem before you start throwing money at it. Otherwise you could end up buying a new car for your radiator cap.
Other problems that can be related is a poor ground, or dirty battery terminals. These are also easy to check and rectify. Old batteries (over 5 years) often need to be replaced. If you can determine how old your battery is you might want to replace it - even if it isn't the cause of the problem you describe. The last thing you need is to go out for dinner and come out into the cold only to find your car won't start.
The alternator is likely the most expensive part of the system. Don't replace that unless you're SURE it's defective. Remember, lose connectors and bolts can lead to poor grounding. Often the gremlin behind flickering lights. But in your case I'd suspect first the belt. If it's a serpentine belt there should be a spring loaded tensioner. Usually you insert a half inch drive break-over bar (a ratchet will do) and release the tension and slip off the old belt. Other vehicles have a tensioner that must be adjusted. Be sure not to "OVER" tighten the belt, as that can cause excessive wear on other parts and lead to premature failure.
In summary, check the belt for proper tension. If you can turn the alternator without causing the engine to rotate then the belt is slipping. Whether it's worn or just lose - it's a simple check. Next, check the battery terminals to be sure they're clean and tight. Check for cracked connectors too, sometimes they crack and that allows them to loosen up. Next check to make sure the black cable going to the engine block is not lose. There are also secondary grounds bonding the engine to the car frame and body work. Look for any broken or lose connections there as well. If all that is good then drive the car to your favorite automotive parts store and ask them if they do free alternator testing with it on the car.
Finally, if it's determined the alternator is going bad then depending on how accessible it is you might want to change it yourself. Most often there's a large bolt that holds it to the engine block while a second bolt is used to hold the alternator tight against the belt.
It's not a difficult job, just one that takes patience. If you change the alternator yourself be sure to disconnect the battery first. First remove the negative terminal then the positive. When reconnecting - connect the positive first and the negative last. The negative is ALWAYS the first off and the last on. Otherwise you risk shorting the battery to ground if the negative is connected before the positive.
Hope this helps.
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The belt is shot, I'm sure, but it is also possible a pulley is out of line. At ten years old the belt is at the end of life and once they start squealing they are beyond hope. The days of tightening V-belts are long gone.
Nothing in the description to make me think the battery is bad, and although it is possible the flickering is bad alternator brushes the belt is still the odds-on favorite. After all, that is what is squealing.
Belt is straight loose on that alternator hehe
Slipping, making the noise
Slipping, not turning/charging
replace cheapest to more expensive...belt, then alternator, then battery
ive been having problems with my ford fiesta 1.4 04 plate its recently been making a repetitive squeaking noise and both headlights and internal lights (radio and overhead light) keep flickering there seems to be no pattern but always does it. Ive had 1 instance when the car turned over but wouldnt keep the the revs so im in 3 minds whether its the belt the alternator or the battery. Any helpful responses would be great and would a alternator and belt be easy to replace myself?
