Click Click Click ...alternator?

MrTeach73 · August 27, 2020

Bought a 2007 Lexus last Friday SE L and love it. Drove all the way from Winchester to Stafford and back the next day. Then didnt drive it for four days.

Car started and i drove 10 min to get petrol. After filling up, the car wouldnt start. Lights would come on but it would click click click...

Anyway called the AA and eventually they came.

Thought it was the Battery but it seemed ok. So they think its the alternator...

Is this what it probably could be?!!?

They charged the Battery a little , jump started it and my wife drove home.

Any help gratefully received.

Herbie · August 27, 2020

This is happening because the Battery is low, quite possibly on its way out.

A starter motor will draw over 300A to crank the engine but in your case it can't supply that. There's enough power in the Battery to pull in the starter solenoid contacts, which then passes power to the starter motor, but once the motor tries to draw a heavy current the Battery voltage drops very low - so low that it can't hold the solenoid contacts in.

When the solenoid drops, Battery voltage climbs back up and the whole process carries on in a loop. The clicking you can hear is the solenoid contacts keep making and breaking, more commonly known as solenoid chatter.

So, it's either the Battery itself at fault or the alternator is not charging it. The chart below wil help to diagnose it. Standing voltage should be as per the chart but when the alternator starts then the voltage should climb to about 14.5V. If it doesn't then it's the alternator.

MrTeach73 · August 27, 2020

Many thanks. That sounds like what the AA man said to my wife.

And should the belt get replaced at the same time as I've heard that it may have stretched ?!

Herbie · August 27, 2020

Yes, for the price of a belt you may as well and then you know it's right.

MrTeach73 · August 27, 2020

Thanks again.

Really annoyed as we missed our flights to see out daughter in Newcastle who was moving into her new apartment because of the car.

Tried to get the garage to do a goodwill gesture and give us the airfare but no luck...

Barry14UK · August 27, 2020

I am sure the AA would have checked this in your case but the click click can also be down to a poor earth. Learnt this with my first proper car when I knew nothing about cars. Car would not always start just giving clicks sometimes, so got garage to check and the posts and terminal connectors were cleaned and reattached. Problem solved which cost me half a crown - well it was a long time ago!

royoftherovers · August 28, 2020

10 hours ago, Barry14UK said:

I am sure the AA would have checked this in your case but the click click can also be down to a poor earth. Learnt this with my first proper car when I knew nothing about cars. Car would not always start just giving clicks sometimes, so got garage to check and the posts and terminal connectors were cleaned and reattached. Problem solved which cost me half a crown - well it was a long time ago!

T`was only yesterday, young man!

MrTeach73 · August 28, 2020

UPDATE!!!

So I used a multimeter on the Battery and it is reading 12.5 is is around where it should be i guess.

Started the car and it went up to 13.7 which i think is low.

Then switched on everything and it dropped to 12.4

Is this confirming that it is indeed the alternator that isnt doing its job?

Thackeray · August 28, 2020

If the alternator wasn't working at all, the Battery would eventually go completely flat. If you could start the car, you could probably drive quite a long way just running down the Battery to provide sparks to the engine. But there might not be enough power remaining in the Battery to restart the car after a longish journey.

The good voltage when standing and the raised voltage when the engine is running suggest the alternator is doing something - maybe it's fine. The figure of 13.7 volts may be because of regulation for Battery temperature or air temperature or something else. If you leave it running it might rise above 14 after a bit.

When it dropped to 12.4 was this with the engine still running?

MrTeach73 · August 28, 2020

Hi yes. The engine was still running when we turned the electrics on...

Herbie · August 28, 2020

Could be a slipping belt - look for glazing on the belt and/or squealing when a high electrical load is on.

Could be loose and/or dirty connections in the charging circuit.

Was the engine just idling when you took the voltage readings or did you rev it - alternator output can vary with spin speed so see what the voltage is when the engine is at about 2 or 3000rpm.

There are a few good videos on Youtube on how to go about testing the alternator on the car, so have a look here for some good suggestions.

Finally, but perhaps most importantly, unless you bought it privately then you really shouldn't be doing any of this anyway. You've only had it a few days so you should take it back to the trader/garage/dealer you bought it from and get them to put it right at their expense under warranty.

MrTeach73 · August 28, 2020

Clickmechanic were going to charge 388 to change the alternator so the garage gave us the money but now it seems no garage will do it for that so I am now chasing the garage we bought it from to sort it and we will give the money back. Such a pain.

Herbie · August 28, 2020

18 minutes ago, MrTeach73 said:

Clickmechanic were going to charge 388 to change the alternator so the garage gave us the money but now it seems no garage will do it for that

I've never used 'clickmechanic' so can't say anything about that but the rest of that sentence gives me cause for concern.

It's not yet been proved that the alternator is the problem so even if a garage did change it, it may not cure the fault. It needs to be properly diagnosed in a logical and methodical way and preferably by a proper auto electrician rather than a mechanical garage or, God forbid, somewhere like Halfords.

I don't know whereabouts you are in Hampshire but a cursory googling shows a 5-star rating for https://www.amtecautoelectrics.co.uk/ and also 5-star rating for http://petersfieldautoelectrical.co.uk/

Above all, remember that you've got rights under the Sale of Goods Act and that the garage you bought it from should be doing all this for you.

is200 Newbie · August 28, 2020

What make of a Battery is installed on the car? Do you have a date stamp on it to tell how old it is? - if its a Panasonic then its the original Battery - i would suggest its your Battery that's on its way out. Batteries on these that are on their way out can cause some strange goings on

I have had the chattering noise before on a previous IS and it was due to the Battery being disconnected after a bit of work was done on it. Connected it back up and it chattered for a bit while turning over then started.