Battery and/or Alternator???

[madnesstiger]

Hiya guys,

I wonder if anyone could help me out a little and possibly save me some pennies?!

Here's my problem, and would appreciate any advice as to which component is likely to be at fault (if not both!)...

1> The orange 'engine diagnostics' light (next to the battery light) had been illuminated for a while whilst I used my 406 (3.0 v6 auto, X-plate) around 4 months ago. It never seemed to affect the performance, and car started first time, everytime.

2> A few days ago I tried to start the car, and wouldn't start. Ended up jump-starting via my trusty Cinquecento! I had to do this again to day to get it going.

3> Once the Pug was running, I measured the battery terminals after turning on the full headlights, rear window heater, full-speed fan/heater, cd player. I got a constant reading of around 14.5v.

4> Left car running for about 10minutes, before switching off the engine.

5> After around 5 seconds, I tried starting the car again with no success, although there was enough power to operate the central locking system.

6> I immediately went to measure the battery terminals, and got a reading of 12.05v.


Note: When I turned on the headlights etc, I revved the engine and did not notice any dimming of the lights at all.


What is my likely problem guys? Any advice is greatly appreciated. Thankyou.

[teamster1975]

Welcome Tiger

If you're getting 14v across the battery when the engine is running you must have a fault with the battery, the car draws a lot of current when you crank it; you may be seeing 12v with the ignition off but as soon as you turn the key the battery won't be able to supply enough current to the starter motor.

[Longintooth]

Have to agree with that - alternator is delivering the correct voltage and your lights remain bright so current ok too. The check light just may be a coincidence of something else that threw a fault code up, you can get a code reader to find what it was and if the fault corrected the light will go out after a predetermined number of good cycles. Cheap code readers are available. As for your starting problem, do we assume this has just got worse with the cold weather, if so it could be your battery is expiring. You can try to condition it and get a bit more life out of it if your are suffering the crunch. To do this you really need to borrow a smart charger that can give a high rate of charge to remove the sulphate from the plates - it effectively boils the electrolyte, then goes to a longer lower rate, then a trickle. The success will depend on whether any plates have shorted or just plain broken up. sorry I just re read your post - you say it has been stood a while, if so it is almost certainly just flattened, BUT older batteries simply don't like being stood without cycling and it may be you have lost it, but you can try the aforementioned.

[Doggy]

All may not be lost - my son's Golf was laid up for a few months & always as flat as a pancake when left for more that 3/4 days. I was certain it would need to be replaced once he got it on the road, but once in regular use has proved OK for the last 5 months. I thought the first real cold morning would kill it off, but so far it's fine.

[teamster1975]

See if you can get an Optimate cheap at Halfords; they may have knocked a few quid off in the sales!

[madnesstiger]

Thanks for the replies

I have taken out the battery, and found that there's some acidy-gunk stuff growing near the terminals, so think it's probably best to replace the battery.

However, after a quick look on the 'net, I've found quotes of between £35 and £87 for a new battery for my Pug.

Anybody have any good recommendations with decent prices? The battery I took out had a code of 046-614 L2 300v, if that's of any use. Its a 3ltr v6 GTX 'Auto' model (Oct 2000).

Cheers again guys. Thanks.

[steve_earwig]

Does it have a bar code? Thin line, thick line, thin line, thin line? The code desn't mean much (I even Googled it), what you need to know is the size, where the terminals are, the capacity (in amp hours) and the cold cranking capacity (cca, in amps). Although this doesn't cover for the possibility the car has the wrong battery in it. There's loads of battery sites in the interweb, most of which seem to say your 3.0 needs the same battery as a 1.8 manual Big engine, auto, should need something pretty massive. This one seems a bit more sane http://www.performancebatteries.co.uk/f ... ttery_info
I can't really recommend anything as I've got no idea myself (and more or less in the same boat). There does seem to be a bit of "you get what you pay for" about it, they start cheap and cheerful, then the lead calciums are supposed to be good but a little pricey, then you get to the glass fibre matt ones, which are meant to be the dog's danglies but for about three times the price of a Halford's special

[teamster1975]

This one seems a bit more sane http://www.performancebatteries.co.uk/f ... ttery_info

Free next day delivery?! Thanks very much for that link Steve!

[steve_earwig]

Oh! I didn't notice that, do they do outside the EU?