Starter motor noisy on cold mornings

Hi, can anyone help with a starter motor noise problem, its ok in the summer or when the engine is hot, but on cold mornings the car starts fine, but it sounds like the starter is staying engaged for a second or two, i noticed this problem last winter but did not do anything about it. Its not really what i would call a "mechanical noise" more of a higher pitched whine, can anyone shed some light into any possibilities. Is replacing the starter motor on a A4 1.8T 1996 an easy job?

I am afraid you need to take it out and clean it. It happens to some people, a lot of small metal bits due to wearing of the cog wheels, from on/off positions.
Other option is the key barrel not rotating back after starter on position to ignition on position.

this is happen on my a4 thought i would need a new one

i will give it a go and let you no what happens