Thinking of getting a 190D...

[Targa-NF]

I was looking at a 86 or 87 190D. The engine sounded a little too tappy.
It is a 4 cyl non-turbo. With only 111,Miles. It was not a lower end knock.
It was a loud tapping. It did not sound like my SD when she needs a valve
tune-up, It was a higher pitched tap tap tap... I have never heard a 190D
4 cyl diesel running before so it hard to compare. Any addvice would be great.
Thanks, Jay