Hi,

My car is Toyota vios year 2010. Recently there is kind of turbine noise coming from the engine bay. I was told it could be due to alternator. I have checked by unplugging the negative terminal while engine running and the engine keeps running. I bought a car socket voltmeter and the reading shows 12.5 (before start), 13.7 (after start) and drops to about 12.2 (aircon on, radio on, light on during idle) and about 13.4 (aircon on, radio on, light on while driving).

Is my alternator spoiled?

Negative terminal of what? If you unsure don't anyhow remove things and start engine. Worst thing could happen is damaging the engine because you meddle without knowing what.

In original conditions, you should see your voltage going up more than 12V when the engine is idle. Turning on other electrical device would make the voltage drop. Driving your car would make the voltage goes up. These are normal electrical specifics.

Humming noise due to alternator are mechanical problem, you may still see normal voltages.
Go get a mechanic to check it up.

hi,

i recently had problems with my alternator not charging consistently and i wanted to save money from buying new one. I stumbled upon this workshop in Jalan Ipoh where they rebuilt and replace faulty alternator parts.

It is a good place to overhaul your old alternator and starter just the way we all overhaul our old engine

The boss is a silent old chap but very polite, i monitored his work and he was thorough and do things orderly, not very common in younger workshops we see these days where everything is about profit and fame, but working attitude kaput.

Due to his excellent work and experience, i decided to share his shop info here, FYI i am not taking any sort of commission, just a chap who praises a good old school workmanship and working attitude

The worker told me almost all alternators can be fixed without buying a new one as the fault is usually due to malfunctioning parts only, replacing it will make it as good as new.

replacing old whining, squealing alternator bearing with new one:



the brushes of my 10 years alternator has worn off, no wonder it causes electrical inconsistency, compare below between new brushes and the worn ones:



i decided to refurbish my starter as well, the brushes was ok but the bush has worn out causing it to vibrate, u can see the scratch black marks on the plate due to scuffing from the starter body when it vibrates, this happens when we crank the engine, anyway they replaced it:



Cost was RM90 for alternator brushes and bearing including labour for removing and reinstalling the altenators, RM45 for starter bush including labour, not bad.
Location:

it is located nearby kem batu kentomen, jalan ipoh at the side of the main road

those coming from roundabout jalan kuching:
a) at roundabout, enter jalan ipoh
b) proceed straight passing through several traffic lights, u will find a caltex station
c) proceed further ahead until u see a signboard going to kem batu kentomen on the left, proceed straight but drive slow after this junction as the shop is nearby already, most people missed it
d) the shop is located besides furniture store, u can see a lot of batteries at the workshop front



Hope this helps

Sorry I should have specified. Negative terminal of battery. The humming noise could be sign that my alternator is spoiled? What are the risks?

By removing the battery, you may damage the alternator and possible other electronic components; including your computer.

When your engine is running, your solenoid will draw high current from both alternator and battery, powering the spark plug. Since you disconnect the battery, the alternator voltage will drop when heavy current is drawn. To counter the voltage drop, the alternator will push up the output voltage. Sometimes it creates higher surge voltage that may fry the electronics.

The battery is there to prevent too much surge voltage happening. Your voltage meter will not able to record these spikes.
Does the humming sound change when you accelerate?

Thank you for the information. The humming sound kind of moving according to the engine acceleration sound. So the reading on the voltmeter could be wrong? I feel as though the car pickup has dropped a little.

my alternator problem also, i start my engine and then remove the -ve plug bamm engine mati, as u guys say i will go tmr

how was the experience? Good? Price reasonable?

btw, it's not RM300.00 to fix it.....it is RM230! Imagine what a coincidence....earlier on today i was quoted by workshop RM2300 for new alternator and now i just pay rm230 to fix it!
difference by one zero 

my hubby will be so proud of me   

Here's the address :
No. 655 Jalan Ipoh Batu 4
Kuala Lumpur, Wilayah Persekutuan 51200
Malaysia
tel: +60 603-62582295

Please call to ask directions when you are near the place cos it's not easy to find. When you see a 2nd hand car shop, you can slow down already and lookout for this shop. It's not a shoplot, it's like those pondok workshop 

Really love u too much with this address,muach

Wow! It's been a long time i've not visited this thread. Glad to hear this place is helping you all

i'm one of their customer bro.. 

   

Greatly thank you for this post, we just fix our vios alternator there for just rm80. Very honest uncle and I remember I fix my last car there 16 years ago and workmanship is tip top. Highly recommended!

option 1) find a garage closer by to remove it then get the alternator fixed/replaced then go back to the garage and install...
option 2) diy, if u have the tools required, its a viable solution. The internet is full of info
option 3) if u want to take that risk..... charge that battery up before leaving and prepare a spare battery to swap in if the worst case scenario comes through