Hi Guys

I've owned a 2004 2.0 DTI diesel astravan for a year now and had 20k trouble-free miles out of it.

I'm told the engine has a timing chain rather than a belt, and it just wants leaving alone. Is this true? It doesn't rattle or do anything uptowards, just wondering there's and scheduled/preventative maintainance (guides?) I ought to do on it.

My other query is about the recent smoke test for the MOT. It scored 1.3 out of 1.50 and the MOT the previous year it got 0.32.

Does this indicate a potential problem (injector cleaner required?) or are these results often all over the map? It was given a full service (by me) less than a week before the MOT.

Any advice would be most welcome