Why does my 2008 Cadillac SRX with the North Star V8 sound like a diesel engine

Hello -- if there is noise like that in the engine, it could be a sign of internal engine wear or damage. Or, it could be a timing concern. I'd highly recommend a professional evaluate your vehicle, because pretty quickly to a trained ear it will be apparent what is going on. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops