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mechanical-expert opinion sought.

1K views 19 replies 12 participants last post by  arcon 
#1 ·
The patient : ST2.2 Mondeo MK3

Age : 9 years

Mileage : 90k

Friday Morning
Jump in car first thing in the morning to go to work... starter not firing, can hear a clicking sound when turning the key. Dash still lighting up ok.

Friday Evening
Get the jump leads on the battery and start up from a neighbours car, and drive round town for an hour to charge it.
Get home, take key out, put it straight back in to test I can start the engine and yes I can.


Saturday Morning
Back to square one - starter not firing, just a clicking sound when turning key, but dash still lighting up ok.

Despite being a chap who knows very little about what goes on under the bonnet of a car, I have done a fair bit of reading online to see if a dead battery is the only likely cause, and I have found suggestions that other elements could be to blame, problems with the starter; cracked bridge plates (whatever that means); voltage issues; to name a few.
I have scoured the car for anything electrical that might be draining the battery while the car rests, and haven't found anything obvious.

Given that I was able to charge the battery back up again after an hours drive such that I could then start the car, does that suggest the battery might not be at fault? Or was that a red herring and in fact just the last few spurts from an almost lifeless battery which is just breathing its last breath.

I'm considering asking the neighbour for another jump start so I can take it down to halfords and buy a new battery. (they only charge a tenner to fit it) although I read online about one guy who forked out to get a new battery, and then days later when the new one was unexpectedly flat, got the experts on it, and established that something else was to blame. Naturally I'd prefer not to follow that path - hence my decision to write this post!

I think I'd like to avoid going to a garage for a full assessment if I can, because this strikes me as the sort of problem that could be exploited in terms of what expensive components they tell me need replacing.

Any thoughts from the experts on here - based on the symptoms described above would be very much appreciated.

Cheers,

Dinelli.
 
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#4 ·
#6 ·
I had this issue.. But only when the engine was cold. Car would refuse to start and click. Jump leads made no difference.

So I resulted in hitting the starter with a hammer and it would fire up and behave all day.. Then next morning when engine was cold I'd have to get the hammer out.

Turned out to be an over tightened nut on the starter which was causing a small gap.

I paid attention at school and realised that tho ha expand when hot, which is why my starter was fine when engine was hot
 
#7 ·
Check connectors to battery and starter are tight ... just give them a wiggle to make sure they are done up well........ If nothings loose do a battery test first or get Halfrauds to test it for you.

Charging a battery where the charger says all is good does not mean the battery is good ... I have a 12v motorbike battery all charged up and showing 12.16 volts ... which actually means its faulty as it should read above 12.4 volts..

The difference between those two voltages can be as much as 75% in the battery.
 
#11 ·
You can see that even amongst people who do know cars this isn't as clearcut as you'd like!

I'm going to waffle on a bit more but one thing which is critical - if you go for a new battery, make sure it is a calcium type. Your car has a charging system designed to work only with this sort of battery., which can withstand much higher charging voltages. An ordinary lead acid battery will work for a short time but will quickly be killed by the higher voltages. Ufortunately this information doesn't seem to have reached some suppliers yet. You may pay a little more for the correct type but it will outlast an ordinary battery by many years. (Not the same as choosing between a standard battery with a one or three year warranty, where you basicailly pay for reserve capacity in the construction to keep it working longer; the battery types are sufficiently different not to be interchangeable. ) Bosch S4 or S5 are examples of batteries with the correct chemistry.

Because of the long life of the battery, as already mentioned yours may be original.
At 9 years old it doesn't owe you anything. If you have the means to give it a proper charge then doing the battery and alternator test signposted by Purple_2l_lx may give you confidence that one course or another is the correct one.

Assuming you don't have a multimeter, I would use the builtin dash diagnostics to display system voltage.
 
#12 · (Edited by Moderator)
You can see that even amongst people who do know cars this isn't as clearcut as you'd like!

I'm going to waffle on a bit more but one thing which is critical - if you go for a new battery, make sure it is a calcium type. Your car has a charging system designed to work only with this sort of battery., which can withstand much higher charging voltages. An ordinary lead acid battery will work for a short time but will quickly be killed by the higher voltages. Ufortunately this information doesn't seem to have reached some suppliers yet. You may pay a little more for the correct type but it will outlast an ordinary battery by many years. (Not the same as choosing between a standard battery with a one or three year warranty, where you basicailly pay for reserve capacity in the construction to keep it working longer; the battery types are sufficiently different not to be interchangeable. ) Bosch S4 or S5 are examples of batteries with the correct chemistry.

Because of the long life of the battery, as already mentioned yours may be original.
At 9 years old it doesn't owe you anything. If you have the means then doing the battery and alternator test signposted by Purple_2l_lx will give you confidence that one course or another is the correct one.

As it started with a jump, and recovered enough to start the car later, your alternator is probably working to at least some extent. If it is working properly, you will see the system voltage rising.

Assuming you don't have a multimeter, I would use the builtin dash diagnostics to display system voltage.
(Press and hold milage trip reset while turning ignition on, then ontinue to hold until display changes to test. Press the button repeatedly to step through various values until you get to "bat". You can start the car with the display shown, it gows back to normal when you switch off.

If you don't fancy startkng doing your own maintenance, then getting battery swapped would worst case cost you a battery. (Make sure you have the radio code, or fitter uses a device to keep it powered during the swap).

Simplest way to check if your battery is being drained by something overnight is to disconnect it. But a weak battery which has just been charging may start a warm engine but not a cold one next day.

Clicking under the bonnet when you try to start is the solenoid connecting. When it does, the starter tries to draw a lot of current from the battery, whi h drops the battery voltage, which makes the solenoid release, which stops the current draw, so the voltage and current to the solenoid recovers and it pulls in again and so on. Hence continuous clicking. One click, it either doednt have quite enough to crank engine or too little to activate main solenoid.

I think the cracked bridge you mentioned is a reference to parts internal to the battery.

Dont rev your car more than a tad if jumpstarting from another car. Your car may put out more volts than other cars are designed to cope with.

You may like to google smart charge for more info about your cars charging system.

You can get a lot of info with a multimeter. Sometimes a battery can show a reasonable voltage but collapse under heavy load. Thats what the battery tester imposes. Watching the voltage when you try to crank gives similar info but specialist has experience and tester not subject to what the car is doing. Swings and roundabouts...
 
#13 ·
Op probably did that yesterday...:)
 
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#15 ·
Is there an emoticon for heavy sigh squirt?
 
#19 ·
Okay, here is a easy way to test your battery and your charging.

You will need a multi-meter - try to get something up from the really cheap chinean ones are those are dreadfully inaccurate.

Once multi-meter in hand, pop the hood, ensure the car IS in neutral, get someone you trust and put then in the car to start it at your command, ensure your multi-meter is set to a good range of Voltage DC, like 20V DC if not auto ranging capable.

Now place your probes on the battery terminals - mind the polarity, + on + and - on -.

Ensure your multi-meter is on and keep your eye on the screen - you will likely have a reading of 12.xx V upwards, if lower than 11.7 then you already have a suspect since the battery is unable to keep a charge and at 11.7 a battery is already flat.

Now let your trusty person turn the key - check the reading - there is normally a drop in voltage as that poor battery pushes all it's guts into your starter motor.

But, if this value drops way low, like 7 - 8 volts, you have a diagnostics - your battery is konk and needs replacing.

And you did not have to get your fingers blackened by all those amp thingies = like.

Now once you get your motor up and running and idling, we will test the alternator - again using the same voltage scale - I'm steering you away from the amps side as people can mess up a whole lot of stuff by fiddling with these setting since the way amps are read is way different.

Okay, the engine is idling - same thing you done before with multi-meter probes on battery.

Now you should have a healthy voltage of probably 13.8 or higher - mine runs normally at 14.22V while idling. This is not the battery voltage any longer - remember your battery is 12 V, but is the charge voltage that comes from the alternator. Now, important, if your voltage reading is something pewny like 12.4 or less, you have a problem - your battery will never be able to charge to full capacity, it is just how it is, take your car to an auto elec to confirm your diagnostics and say to yourself ouch as alternators are bloody expensive.

But it does not end there, everything in your car runs off DC voltage, but your alternator generates AC voltage - that is a problem as the two are not compatible, so the alternator also have an regulator, which is a piece of electronics to make the AC voltage turn to DC, but note, that DC voltage will always have a ripple component, in other words it's DC, but not purely flat, there is a bit of sinus wave behaviour to it that comes from AC.

If your Voltage reading on the multi-meter while the engine is idling jumps up and down quite a bit, then you may have a problem with the regulator that is part of the alternator - again see your local auto elec to help you out.

Enjoy the ride.
 
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