Excessive engine ticking noise 1.9TDI AFN

[Jimbob1981]

Looked all over the forum but can't find this one!

I have owned my 2000 110 TDI Estate from new and to date I have covered 153K. I have been running the car on a 70/30 blend of Diesel and KTC for the past few months with no ill effects.
Yesterday I covered a run of about 450 miles at an average motorway speed of 70mph, I usually do small 5-20 mile trips and then every few weeks when working away I might cover up to 500 miles in a day.
Today I started it up with the usual loud ticking which deadens in a few seconds after the bowls of the engine get covered with oil, but as I drove it away the loud ticking persisted.
It got quieter after a few miles but any hard accelerating would bring this ticking back which would stay for a few more miles.
I used to get this with the Hydraulic valve lifters on my Mercedes 190 but the Passat is usually pretty quiet.
The trip today was about 20 miles in total and the ticking was there for the majority of the drive.

Anyone got any ideas or suggestions, Cheers

[a8 tech]

poss small end,try to locate noise by using a long scew driver placed in the location and putting your ear to the scew driver to hear the knock,it should be louder when revved

[Jimbob1981]

Cheers A8 Tech, I'll do as you say. Although would this sound usually happen imediately or gradually over a period of time? The reason I ask is becuase it happened literally over night!

[stevegrass777]

I would take the rocker cover off and see if there are any signs of play or wear.
It is most likely to be a top end problem like a tappet or injector problem.