Hiw much will a new alternator cost?

If the problem IS the alternator, a new one should be about £100-£150 fitted.

It dont sound like an alternator fault, that is - an actual fault with the alternator(and dont THINK about an alternator until you KNOW its the alternator - and even if it is try breakers yard/e-bay for a replacement - with an r reg a new one could cost a substantial proportion of what the car is worth)

If you have a electrical voltmeter (you can get a cheap digital one on e-bay) connect it to the battery terminals (take care not to short the leads)

It should read around 12v -

start the car (dont put any lights on)

the reading should go up to 13-14v

If it does then the alternator is ok

If it stays at around 12 it DOES NOT automatically mean there is a fault with the alternator

The car has a belt going round the alternator

Does it have teeth or is it just a "V" belt (most modern cars have teeth but an R reg may have a "V" belt. If you know where the alternator is just have a look at the belt that goes around it, you should be able to see or feel if it has teeth

(if you can press the belt just see if you can move it - you should only be able to push it in by around 1/2 inch)

If its a "V" belt it may need tightening- - If it does need tightening and you go to garage to have it done then I would advise having a new belt fitted. It dont cost much extra. (Last time I had a belt tightened it snapped a few days later cos it was an old car with an old belt.)

(Even if its a toothed belt - if its REALLY slack it can be jumping over the teeth (or its teeth may be severely worn) on the alternator or engine and possibly jambing in wheels that keep it in tension)

The squealing and lights dimming sounds like the belt is slipping (cos it needs tightening) - (mine did exactly the same)

You may be thinking new alternator but are you right? Usual symptoms are ignition light glowing and/or flat battery. Check the belt tension as the squealing is likely to be a slipping belt. You should be able to deflect the belt about half an inch with thumb pressure at it's longest travel. Any more and it is slack. A simple test for alternator failure is to point the car at a wall/fence at night, switch on the headlights and rev the engine up and down. the lights should brighten at the high revs. If not the alternator is suspect.

Bear in mind it may be the battery. If the batt is over four years old it will be past it's best.

Rough idling etc is nothing to do with the alternator or battery.

http://www.startermotor-alternator.co.uk/ were quite cheap when I got a new one, about £80 for the parts, though you might be able to find a local auto electrician who can refurbish yours for cheaper.

Squeeling: likely to be a belt slipping, though also if when changing gear could be the clutch

Dimming headlights: depends what you are doing, if using a lot of power then electrical supply problem but could be a lot of things

Rough idling: More likely to be the fuel system or spark plugs

Chugging: Fuel or spark plugs

Fuel problems can be cured easily with high octane petrol for a couple of tanks (the ecpensive stuff) plus a bottle of wynns injector cleaner, and new spark plugs (cures a lot when it is cleaner inside)

Slipping belt - work out which one it is and can be fixed easily

When im ill Doc i come and see you, your cars ill Doc, find a mechanic, you may not need an alternator

the alternator only keeps battery charged , i think you got other problems , go to auto electrician

auto parts store will often test for free and give you a price.