[VolvoRob38]

Last night I lock the car with the manual key so that the alarm wouldn't be activated and drain the battery. Ive just been out in the car and started up as normal, although I can hear a squeek like a belt is slipping.
Can someone please confirm if I have a timing belt or chain on my c30 1.6d 2009 (photo attached). Reading online it sounded like it had a chain, but looking in the engine I can see a plastic case that makes me not so sure. This does seem to be directly above the alternator belt though, so possibly something else. Ive not taken the engine cover off for a proper look. which is still getting very hot I might add.

I tried checking the battery voltage, not sure if I have it on the right setting because I read set it to 20 on V, but as there are two Vs on my multimeter I wasn't sure what the additional squiggly / dotted lines mean.
Testing on this setting anyway shows 11.65 with engine off and with engine running, so I assume there is still charge in the battery but not being charged by the alternator?
I dont understand why it died last night, but today starts ok, and charge in the battery (assuming thats the correct setting/reading). Unless that 11.65v is from the jumpstart and drive home last night?

I reckon I can do the alternator, not so sure about the timing belt. Im at 69k now so it probably due a change, if its a belt.