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FAULTY ALTERNATOR?


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My Battery light first came up sometime last year, it would come up for a minute and go back off. Took it to the garage and I was told everything seems fine and they can't see anything wrong with either the alternator or the Battery. Fast forward, few months later I was embarking on a 2hr drive home and 20 minutes into journey while on the motorway, my engine shuts off in motion and Battery light and check engine light came up.

I was able to quickly get to the hard shoulder to try find out what was wrong. I tried to start the engine again but it immediately shuts off. After realising my aircon, cooling seats, radio was on, I turned everything off waited for about 1 minute and push the start button again, Everything seems fine but the moment I turned on the aircon, engine shuts again.

I turned the aircon off, turned on the ignition again, everything was fine and I was able to complete my journey without the journey with aircon and radio off.

Took the car to the Mechanics the next day, they diagnosed the car and I was advised to buy a new Battery first and see if the problem persist. Got a new Battery next day and everytime I tried to switch on the aircon, engine shuts off. When I turn on just the heating, it's fine but the moment I try to switch to aircon same thing happens. So I decided since its not summer, I don't really need the AC, I'm just gonna stick to heating for now. Drove it around for few days, then yesterday I noticed everytime I come to a stop by the traffic light, Battery light comes on quickly and flashes then goes off when in motion. Someone said maybe it could be the alternator connector. What do you guys think?

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What did the mechanic actually diagnose? How long have you had the car and what kind of service history has it?

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Is air con compressor clicking in and out OK?

AC pulley may be seized and affecting the drive belt that drives the alternator to charge the Battery.

run car and check under bonnet that belt is all ok when AC is turned on and off.

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53 minutes ago, Texas said:

Is air con compressor clicking in and out OK?

AC pulley may be seized and affecting the drive belt that drives the alternator to charge the battery.

run car and check under bonnet that belt is all ok when AC is turned on and off.

very good answer, i had a similar problem with my alfa 166 years ago and this was exactly the cause & issue

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6 hours ago, Texas said:

Is air con compressor clicking in and out OK?

AC pulley may be seized and affecting the drive belt that drives the alternator to charge the battery.

run car and check under bonnet that belt is all ok when AC is turned on and off.

I will try this. I don't know nothing about the mechanical aspect of cars. Earlier when I was at the Mechanics who happens to be a family friend, we noticed when we noticed a burning smell when we switched on the Ac, this time engine didn't go off. It was struggling to stay on at first, the guy reved the engine a bit and the engine stayed on and AC light starts blinking. He didn't have enough time to do more checks as he had to go somewhere. I was told to come back tomorrow. Everyone keeps saying it seems like it's the alternator. I don't want to just go Ahead and fix the alternator just for them to come back to me and say it's something else.  Especially not after my local garage just game me £490 quote to replace alternator. 

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7 hours ago, Mr Vlad said:

What did the mechanic actually diagnose? How long have you had the car and what kind of service history has it?

I have had the car for 2 years and it's has full service history. 

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“Burning smell when AC is turned on” sort of points towards what I said you should (get) checked, AC pulley is seized and not allowing belt to drive the alternator and I would suggest you now prob need a new belt as well! 

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The air conditioning compressor has an idle pulley that turns continuously about its bearing when the engine is running.

When the air conditioning is turned on, the compressor clutch pulls the pully towards the compressor shaft coupled to its own separate pulley and the compressor runs. Notice the pulley splines bending to allow the pulley to engage pn the compressor pull

There is a gap of about 0.4 mm between the two pulleys, depending on the manufacturer.

Check that the idle pulley bearing rotates freely, there is no play and makes no noise. Make sure the belt is properly tentioned and does not slip.

If the idle pulley checks out  check that the  compressor rotates freely. You may have a seized compressor.

Chris.

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Question to Smothope…..do you use your car with the AC On all the time or only turn it on occasionally when it is uncomfortable hot inside the car?

reason being is that the AC Should be used on a regular basis ( I suggest 30 mins per month minimum) to keep it in a fully functioning condition so as not to allow things to seize up and for gases and oils to circulate around the system.

FYI I run my 250 with AC On all the time and just adjust the temp to suit conditions, in AUTO mode it will run if required.

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