164 km. According to Baidu map, it takes 3 hours and 5 minutes from Kulun to Tongliao 164 km, and the driving route is provincial highway 304 and 305. The specific steps are as follows:

1. Start from Kulun and drive 57.6 kilometers to provincial highway 305.

2. Secondly, drive 73.7 kilometers to reach National Highway 304.

3. Finally, drive 3.5 kilometers to Tongliao.