Why is my Audi 80's engine making a rattling noise on startup?

Whenever I start my 1990 Audi 80, I hear a loud rattling noise coming from the engine. After a few minutes, the noise goes away and the car runs smoothly. What could be causing this and is it something I should be concerned about?

It is likely that the rattling noise is due to a worn or loose timing chain tensioner. If left untreated, it could cause damage to other engine components. I would recommend taking your car to a mechanic for a thorough inspection and potential replacement of the tensioner.

Another possible cause of the rattling noise could be a failing oil pump. It is important to check your oil level regularly, as low oil can cause the pump to work harder and produce a rattling sound. If this is the case, have your oil pump inspected and replaced if necessary.

I had a similar issue with my Audi 80 and it turned out to be a problem with the ignition coil. If the coil is failing, it can produce a rattling noise on startup. I suggest having your coil tested and replaced if needed.