00 tdi golf- no start

Was driving my tdi golf yesterday, and it failed on me, just cut out, tried starting her again but nothing, i felt maybe the diesel filter was blocked as it had given me trouble before, but not for awhile now, then i thought injector pump was frigged. when towing it home in the eve, i said id try jump her to see like, but nothing, then after a min or so of doing it oil light started flashing, I was worried, i replace sump two weeks ago, and was beginning to worry about the job i had done. alas i checked oil, it was sound, but foolishly when i sumped her two weeks ago i drve her (was not leaking much) to where there was a sump for nothing and changed it topping her up with 5w-40, ot much mind you, no I put in sump and replaced it with same oil as i only serviced her week prior to that. is there a chance oil was too thin and has gone up the o rings?

tdi golf would run on low ash oil as that oil should be ok you reused,any pipe on fuel line/filter including seal gone and drawing air.i had one in and diesel leaked out due to bad seal on filter,had to get a filter off vw as the motor factors ones kept leaking.think it may need diagnostics to be looked at for fault codes.