Determining whether you can reuse diesel engine head bolts depends on several factors. While it's generally recommended to replace head bolts whenever you remove the cylinder head, there are situations where reuse may be possible. Here are a few considerations:

1. Manufacturer guidelines: Consult the manufacturer's recommendations for your specific engine model. They may provide guidelines on whether head bolts can be reused or if they should be replaced with new ones.

2. Bolt condition: Inspect the head bolts carefully for signs of wear, damage, or stretching. If the bolts show any signs of deformation, such as stretching, corrosion, or uneven surfaces, it's generally advisable to replace them.

3. Torque specifications: Head bolts are typically designed to be used only once, as they are often designed to stretch during installation to create the proper clamping force. Reusing stretched bolts may compromise the integrity of the seal and the overall performance of the engine.

4. Engine history: Consider the engine's history, such as the mileage and maintenance records. If the engine has undergone significant stress or has a high mileage, it's generally recommended to replace the head bolts to ensure a proper seal and prevent potential issues.

5. Cost-benefit analysis: Replacing head bolts is a relatively inexpensive precautionary measure compared to the potential risks and costs associated with a failed head gasket or other related issues. Considering the critical role of head bolts in maintaining the integrity of the engine, it's often advisable to err on the side of caution and replace them.

Ultimately, the decision to reuse or replace head bolts is best made after careful inspection and consideration of the factors mentioned above. It is always recommended to consult a qualified mechanic or follow the manufacturer's guidelines for your specific engine to ensure optimal performance and reliability.