Is my alternator failing?

[razvvva]

Hello,

My car is a Ford Focus Mk2 2005, 1.6 tdci 109 hp

A few days ago I started my car, run for about 100meters and I had the battery light coming up on my dashboard(never had any light coming up the dashboard before) and a whining noise coming from under the hood, so I went back home and got my multimeter to check the voltage values at the battery. The values while idling without any consumers was about 13,5 and when I started the ventilation,radio and headlights it dropped to 13,1 so I went ahead and turned off the car. After 2 days I went ahead and started the car again - 13,5v again  but after a few minutes idling the voltage went to 14,45v without consumers and 14,3 with consumers,it stayed like that for a few minutes, then I went ahead and backed up to leave..  surprise, the battery light coming up again and the whining noise when moving(it is more pronounced when the car is moving) and the voltage dropped again. What do you guys think? Never had any  problem with my car starting, winter or summer it was still the same, perfect start.

For the record, I replaced my battery in may of 2018 with a Varta Blue 72ah.

[isetta]

Have you checked the alternator drive belt / tensioner?  Don’t know about the 1.6tdci but the 1.8 tdci has a one way clutch built into alternator pulley. They can fail so that alternator is not spinning as fast as the pulley.

[razvvva]

I have checked the alternator belt visually, and it doesn't seem to be lose or anything.. If I remember correctly even this belt is new, being replaced last year on june.

Any more ideas?

Just for more context, I have done the following things to my car in the last few days, maybe someone can tell me if something could have happened:

1. Monday, I went to the mechanic for an oil and all filters change,and the Air Inlet Manifold Hose Pipe(1440440) replacement(the one that is pretty close to the alternator with a sensor)

2.Tuesday went to the self car wash, went ahead and I had also pressure washed the radiator with  water, but with the hood closed(i dont know if water can go through the radiator to the alternator); made 30km the same day without problems

3. Thursday I used the car for another 30km without any problems; when I started the car again the problems started.Where I live it was very hot(30-35c) these days.

[MLovatt]

This sounds to me like the sprag clutch in the alternator pulley as mentioned in a previous post.. 

[Dee_82]

Disconnect the battery and check the terminals on the Main earth strap to the chaise  (to the right of the battery on to the mount for the strut, remove the stud and clean the threads up as well) 

check and clean the terminals and posts on both battery posts.

Check and clean the terminals on the alternator. 

With it all plugged back in again and the engine running, check the AC (NOT DC) voltage across the two battery posts. (AC voltage here can indicate a failed diode on the alternator.)

you really should be putting out about 14v when started but Id be more interested to know what happens to the voltage when you turn on the HVEC fan on to full and turn on all the High beams and brake lights.

I dont remember a clutch on the 1.6 alternator pulley but I may be wrong on that. When my alternator went it started doing all sorts of crazy stuff, eventually whilst bombing down the outside lane over a bridge on one of the busiest roads in Scotland the car cut out without warning. nothing worked, had to freewheel off the motorway without hazards and pull over, probably one of the most bum clenching moments ive had in a car!

The irony for myself was that I had a replacement alternator in the boot and was heading home to fit it! anyway, point is, dont mess about with it, if its on its way out, fix it.

[razvvva]

Thank you both for your answers..

The battery terminals aren't corroded because I've put vaseline around them when I fitted the battery last year..

As I previously said, without anything on, car idling, the voltage is 13,5 but as soon as i turned the ventilation to 2(not AC),radio and low beams the voltage dropped to 13,1(I was afraid to go further with the testing thinking that a low voltage can actually fry some electrical things).

Is a new alternator gonna resolve the hassle? Honestly with all the 30000 things that can be broken in these alternators I think is better to buy a new one?!

Is Denso Dan930 a good alternator?

[Westville]

Have it professionally assessed by an auto electrician (not a stealer) otherwise you might be fixing the wrong problem

[razvvva]

I have been reading forums back and forth in the last 48 hrs.. and I have actually read identically stories to mine, and they all had to replace or repair the alternator in the end.. Honestly, I think this is my problem also.. I cant see any other reason:new battery(only 1 yr old),new transmission belt(1 yr old), and the alternator charging 13,5v and then suddenly changing back to 14,5v and so on, from what I read it could have been also the voltage regulator in the alternator but this theory proved to be wrong because the alternator charged my battery with 14,5v for a few minutes before going back to the 13,5v situation and dropping further more with more consumers..

Does somebody have the Denso Dan930 alternator on their car? Does it come with a voltage regulator included? Do you need anything else to be put on it before you replace?

[isetta]

I don't know your particular alternator but in my experience all alternators in at least the last 40 years have a voltage regulator built into them inside the casing. Apart from the main thick output wire on the alternator (usually held on my a nut) there is probably another smaller plug with 2 or 3 thin wires on. Have you checked that connector plug for being on properly and clean terminals. I believe the signals it receives on that connector have something to do with telling it to alter voltage output.

[razvvva]

In the end it was the alternator.

Got it replaced and now the car seems to work, the voltage stays at 14.25-14.30 with AC,radio and low beams.

But now I have another problem.. I have run with my car for about 20 km after the alternator replacement and the engine seems to be more rough, making more noise and vibrating more.. Also when I start the car or when I put in neutral the engine rpm seems to fluctuate a little bit. It is normal after an alternator replacement to have these kind of simptoms? is the computer recalibrating or something?

[FatHead1979]

On 9/13/2019 at 3:58 PM, razvvva said:

In the end it was the alternator.

Got it replaced and now the car seems to work, the voltage stays at 14.25-14.30 with AC,radio and low beams.

But now I have another problem.. I have run with my car for about 20 km after the alternator replacement and the engine seems to be more rough, making more noise and vibrating more.. Also when I start the car or when I put in neutral the engine rpm seems to fluctuate a little bit. It is normal after an alternator replacement to have these kind of simptoms? is the computer recalibrating or something?

No, replacing the alternator shouldn't cause the engine to not run properly.  It doesn't need to be "coded" to the car like injectors on some engines.