08 T5 2.5 Occasional Start Problems

[T54Motion]

Hi all hope you guys can help.
Recently when starting the T5 08 2.5 mostly with a warm engine from a short trip, it fails to start but if I try again it starts most of the time, I haven't been stranded yet!
I connected a battery meter, the alternator chargers at 14v and with the engine off the battery reads 12-12.5v
When I have problems starting the van the battery readout goes down to about 8v.
I have a Calcium battery unknown age came with the van, I thought it would be the battery but got it tested and the test report came back 87% health and 100% charge.
Thanks
Peter

[gregned]

Hi Peter.

When you say, you have trouble starting.
Does it crank but not fire or does it have no cranking or slow cranking?

[T54Motion]

Hi, thanks for the response!
It seems to have slow cranking.

[gregned]

Slow cranking would be indicative of a flat battery, can you confirm that it is charging. Could be an intermittent alternator, bad earth or intermittent battery. Can you borrow a battery?
I know you had the battery tested, but if it's not put under full load or under heat stress to simulate under bonnet temps it's indicative only and can't be solely relied on,

Hopefully Drivesafe can chime in and give you some advice on your problem?

[Sunny43.5]

Check the earth connections from the engine to the chassis , I had a similar problem many years ago with my T4 there is a separate cable from the engine to the frame .

[T54Motion]

Thanks for the info, I will try them and report back!

[T54Motion]

Finally got around to changing the starter motor (a real pain!) and voila! Problem fixed!
Thanks for your help.