To find the timing marks on a Toyota 2C diesel engine, you will need to:
1. Remove the valve cover.
2. Look at the camshaft sprocket. You will see a small dot or mark on the sprocket.
3. Look at the crankshaft sprocket. You will see a small dot or mark on the sprocket.
4. The two dots or marks should be aligned with each other.
If they are not aligned, you will need to adjust the timing belt.
