Hi guys,
I have a 2005 2.7D S type. In the course of the last 2 years, I have had 2 new batteries( 1 replaced under guarantee) but the problem of battery power still existed.
Last week, after taking it to my local garage with the same thing still happening, they advised that a new alternator was needed. So,£522 later, it was fitted, and, surprise surprise, the same things are happening.
It turns over very sluggishly and when it does start, the park brake will not release, so I have to disconnect the battery to release it, start and then reset all the windows, radio codes clock etc.
I am now at a loss as what to do next.
Any advice would be appreciated please.
Thanks.

 

How often do you run the car , maybe get a battery minder for it .
Also charge the battery and get a load test done , brand new battery's can be duds!
Check and clean terminals on battery and leads , check earth to body
An easy test is to check the car for a parsidic draw!
Here is a link with instructions and things to watch out for ,
It should be under 50ma draw !


You have 3 fuse boxes to check , eng bay,under dash & in the boot/trunk .
and you need to open your drivers door and boot and wait till the car goes to sleep after about 15 mins the boot and dome light will go out to tell you the car is asleep then start your test.

Failing all that I'd say your starter is pood and drawing too mutch current !
Good luck !

 

Many thanks for that information. I'll try the draw tests as you directed.
How do I check if the starter motor is drawing too much current?
Regards,
Steve.

 

By the way, the car is used daily. On the odd occasion it may be unused for maybe 1 day.

 

It's baisicly the same test but using an amp clamp and an amp meter with more than 250a read out so its not genraly a tool you'll have at home !
Check out the link below genral idea anyway !
Yours being diesel I'd say should be pulling around 180a
Don't quote me on that , your local sparkie should have specks on it any way!
Really thou if your battery is full and tests fine and cables are all good and it still windes over slow then you will be buying a new starter!

 

My hunch is a wiring problem reducing the flow of current to and from the battery. This could affect both the charging system and the starter circuit.

With a voltmeter, you can run a very simple diagnostic routine known as a voltage drop test. This simple test verifies the ability of a circuit to deliver the required current flow under load. Please keep in mind it only works UNDER LOAD, so ignore any readings with the circuit at rest.

This video offers a good explanation:


I highly recommend a digital voltmeter with a min/max recording feature. I have my trusty Fluke 88 and you would have to pry it from my cold dead hands to take it from me, but even a $10 cheapie will work. An analog (needle style) will also work, but you have to be very careful as it's easy to drive the needle in the wrong direction or past the end of the scale and damage the meter.

This test beats disconnecting, cleaning, and testing wires with an ohmmeter. It will even find faults an ohmmeter can't find.

Because the battery is in the back, you will need one long jumper. A length of 16 wire will alligator clips at each end is perfect.

To start, make sure the battery is fully charged. Put your meter's red lead directly on the + battery post. (I drive a small sheet metal screw into the post as a place to connect the test lead.) Using your long jumper, connect the meter's black lead to the big fat power terminal on the starter. Set the meter to DC volts. You might see battery voltage right now, but ignore that reading.

Crank the starter and see what the highest reading was when the starter was under load. Ideally, the reading should be as close to 0.000 VDC, indicating a theoretically impossible perfect conductor. In practice, any reading under 0.500 VDC is good, indicating only a slight loss of current carrying ability between the battery and starter. That was the test of the positive side of the circuit.

Now let's test the negative side of the same circuit. Unhook your meter and move the black lead to the battery's - post. Connect the red lead and long jumper to the case of the starter. Crank the starter again and look for a reading below 0.500 VDC.

If all is good there, let's test the ability of the charging circuit to get those pesky electrons moving between the alternator and the battery. Unhook the meter and put the black lead on the battery's + terminal. (Not a typo, although it seems backwards.) Connect the red lead on the fat output terminal on the alternator. Start the engine, and turn on the headlamps and manually set the heater fan to high to load up the system. Once again, you're looking for 0.500 VDC or lower as a sign the wires can deliver the current flow being supplied by the alternator. That was the positive side of the charging system.

Repeat the test for the negative side. Put the red lead on the battery's - terminal (once again, not a typo). Put the black lead and jumper on the alternator case. Start the engine, load up the charging system, and look for 0.500 VDC or less.

Run those four quick tests and let us know the results. I bet at least one will be much higher than 0.500 VDC.