How often should the cam belt be changed on a 1996 Vauxhall Astra Estate car with GM 1.7 DTL Diesel Engin?

Vauxhall doesn't specify a mileage interval for cambelt changes on the 1.7 DTL engine in a 1996 Astra; instead, they recommend a time-based replacement at 5 years. This is regardless of mileage.

However, it's crucial to consult your owner's manual. The specific recommendation might vary slightly depending on the exact model and any service bulletins issued since the car was new. Even though it's time-based, exceeding the 5-year mark significantly increases the risk of catastrophic engine damage if the belt fails.

Therefore, if you don't know when it was last changed, it's best to have it replaced immediately. The potential cost of a broken cambelt far outweighs the cost of a preventative replacement.