ml 270 cdi alternator

[Gazz270]

alright guys,i have a bit of a strange problem with my alternator,
whilst driving around the battery light illuminates on dash but on tickover it goes off,but the cars been starting ok.
last night we were out with the lights on and wipers and heater and the car stalled and wouldnt start without jumping it,ive checked it all out the battery is fine and seemed to charge ok on tickover but whilst driving nothing,i am thinking it may be a pully fault but it seems to turn ok,
thinking of trying this first before shelling out for new alternator.

cheers in advance
gazz

 

[BlackC55]

Check the charging voltage firstly. It should be 14V to 14.4V engine running.

 

[Gazz270]

cheers for the quick reply ollie,
on tickover its bang on 14.4v,
i can rev it while stationary and its all fine but as soon as you start to drive it stops charging and light comes on,

 

[Jane270ML]

Check all the wiring & connections from battery to alternator, & just as important, all earth connections.

Sounds like something's losing a connection when car is moving, so not charging properly.

Also, have the ignition switch checked.

 

[Gazz270]

all wiring seems ok,not really checked ignition other than turning key,still drawn to the pully but then again that moves freely,

 

[dokalj]

You need to put your vehicle on STAR. Get down to a good Indie.

 

[Gazz270]

update

just a quick update,took the alternator off to get tested,whilst doing this a piece of metal dropped out looked like something broke inside and must have been shorting out,put it back on and it was charging fine just a quite bad vibration from it,i can only asume they are balanced and whatever this broken bit was it was part of the balancing,
got a recon alternator from alternatorman in portsmouth,rang him yesterday morning and ordered it and paid for it over phone and it arrived 730am this morning.
£160 for recon with free overnight delivery and collection of old unit,pretty good i thought.

 

[jay1983]

How hard are they to remove/refit

 

[Gazz270]

not too bad really,ive done one before laid on my back underneath but this time i dropped the turbo off aswell and you can get it all from above,took about 2 and half hours with a butty and a brew about half way through,just remember its watercooled if you do it from underneath wear some safety glasses because you will get coolant in your eyes.

 

[Jane270ML]

a piece of metal dropped out looked like something broke inside and must have been shorting out,put it back on and it was charging fine just a quite bad vibration from it,QUOTE]

Well spotted, glad you're back up and running & not a bad price for a recon unit.

 

[Gazz270]

thanks,couldnt fault the price,next cheapest was £240,
12 month guarantee aswell.
he does starter motors aswell,im going to send him the starter off an old mini digger i have to see if he can do anything with that,its not turned in 4 years so i will be impressed if he can fix that.

 

[jay1983]

its watercooled if you do it from underneath wear some safety glasses because you will get coolant in your eyes.

this is the part that puts me off as its not a normal alternator. I may do it from underneath as I don't want to remove turbo if I can help it

 

[Gazz270]

so long as you drain the system theres only about 150ml in the alternator,keep
an eye on the little rubber gasket that fits between the alternator and block,its a dealer part,its only a fiver but they've got to order it so it would mean another day off the road,