I had my truck at a dealer about 4 months ago. The head was pulled on the passenger side. Since it was finished there has been a popping noise coming from the engine compartment. It sounds like metal expanding. It's loud enough that I can hear it from inside the cab going about 15 mph. Any ideas? Manifold torqued incorrectly??? It's not a tick from an injector but a loud pop.

 

It's the dealers headache not yours, or it will be. Tell them the prob and tell them to fix it. Any work should be guaranteed for 12 months or 12000 km's (whatever in miles).