Thanks litch it is quite reluctant to turn over il investigate tomorrow.The 300TDi normally starts straight away without any pre-heating regardless of the external temperature so if you are having this issue at this time of year (i.e. not cold yet) then yes, you have a problem.
You ask if it is the battery, is it turning over ok? If so then the battery is ok.
You should check the glow-plugs, make sure they are working (both the circuit and the plugs themselves) and if either is faulty then you may have found the problem but as I said, the 300TDi doesn't normally require any pre-heating anyway. Luckily checking the circuit is a simple electrical check and there is a pre-set timer-relay which also activates the light on the dash. Replacing a glow-plug is little more than replacing a spark-plug in a petrol engine, just take care and don't snap it if seized.
I had a glow-plug fail on me once (on my old 2.5NA D lump), took them all out and checked them on the bench and it was easy to see the faulty one, replaced them all though.
Is it actually cranking slow or cranking at the normal speed but just taking a while to catch? If normal speed the leak off pipes may be letting air in and the pump is having to reprime on first start of the day. I've just replaced mine (also a 96) as they were getting a bit frayed and loose. 1m of pipe was £3 ish od ebay.
Op's profile says Def 90 so wont have a sedimentorOr sedimentor playing up, one of my old disco 1's did this at this time of year aswell, couldn't undo the pipes on it so i cut the pipes and bypassed it running a fresh piece of pipe from tank-lift pump once i was happy with it i removed the sedimentor and bin'ed it
Op's profile says Def 90 so wont have a sedimentor
if it is just cold mornings battery would be my choice you can prove it by using a jump pack or jump leads for the first start next cold morningThanks litch it is quite reluctant to turn over il investigate tomorrow.