Completely Dead T25 DG

[Blrsjer]

Hello all,

So I’ll start this post with a small story: It’s a cold autumn morning and I go to start my T25 DG, she starts up first time and whilst idling begins to die a little on me, I rev her and she stalls. Go to restart and nothing, just a slow cranking noise that gets weaker with each try. I try a few more times and now nothing completely dead, I turn the key and absolutely nothing happens no noise at all, completely dead. The lights are fine, windscreen wipers too.

I decide to try a jump start but still absolutely nothing. Take the battery out and it’s definitely not right, it’s sounds like sloshing water and when I try to charge it it sounds like it’s fizzing. I try with another fully charged battery I have lying around, this is less powerful at only 43ah. Again lights work and so do windscreen wipers indicators etc, not quite as well as before. I turn the key and again nothing.

I’m a bit baffled to be honest, I’m assuming it’s probably a dead battery and the charged one isn’t powerful enough to start the starter motor. However I also have concerns the starter motor may have packed up completely, however prior to this I had had no problems starting and no indication of the motor beginning to give up on me.

Before I shell out for a replacement battery I wanted to check here if anyone had had similar experiences or could point me in the right direction of what’s gone wrong.

Thanks in advance. Wasn’t sure whether to put this in the electrical or mechanical section!

[maxstu]

Put a multimeter across battery terminals and check voltage. Anything below 12.3 will struggle to start the engine.

[Blrsjer]

Forgot to mention that! I tried that too, both batteries are operating at about 13v and 12v respectively.

[AngeloEvs]

I would check the wiring to the starter motor, condition of battery connections, etc, also the ignition switch.

[TONYT25T25]

Best to try when its daylight so you have better visibility of issues, when cranking do you have the lights on and do they fade, the battery will slosh if you move it around but be careful as obviously it has an acid content.  Continually trying to crank the engine on a dodgy battery will draw current and possibly overheat the battery and cables.  Worth having a good read of previous posts on the forum to narrow down your issues so see if it highlights your problem.  In meantime I would disconnect it.

[maxstu]

Make sure you have a decent battery that holds a charge. 12 not good. 13 but fizzing not good.
Thoroughly clean the battery terminals with wirewool. Then the same for the cable terminals. And again for earth strap post under drivers seat.
And again for gearbox earth strap.

[Mr Bean]

When you say you tried a jump start was it from another vehicle with a fully charged battery i.e. one known to be good? Fizzing inside a battery under load is a sure sigh of high internal resistance - classic duff battery.  
Re cranking volt drop I Goggled this:
Question: How many volts should a starter engage? 
Answer: While cranking, check the voltage at the starter terminal. It should also have a minimum of 9.6V. If it does not, remove and clean the cable connections.
For my part I have seen sub 10V in freezing conditions but wouldn't expect to see it so low in present weather conditions. A poor connection somewhere between the battery positive terminal and the starter terminal could result in volts being lost on the way and at typical starting currents could be generating a lot harmful of heat at some point. Checking at the starter terminal is the only sure way of knowing what is really going on. I did have an intermittent starter connector terminal open circuit on My WBX and found some kind of coating on the terminal which had to be abraded off to guarantee a start every time. Puzzled me for ages as the nut had been well tight and I only discovered it by clipping my multi meter direct onto the starter motor thread . I suggest doing the multi meter test at the starter terminal with a known good battery. Needs two people really. Good luck.