how to get rid of exhaust smell in cab?
Check for exhaust leaks with stethascope + hollow tube to zero in and repair as required. Clicking when cold and going away when hot = exhsaust leak ussually manifolds
Yep, most likely exhaust leak at manifold
Search GMC Sierra 1500 Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
GMC Sierra 1500 Experts