I just got a camping grill. I hooked up the propane tank and it makes this loud ticking sound. What is it?

It is a hand-me-down grill. I have cleaned the heating element. When I go to turn the grill on, it ignites normally, but makes this loud, fast, clicking or ticking sound. I'm afraid the propane cylinder is going to blow up in my face. Does anyone have any idea why this ticking sound occurs? Is it normal?