07 Murano slight power issue

Was having trouble with my car hesitating to start/ weak start up, and found out my battery obviously needed replaced. So I replaced my battery two weeks ago, so this is a brand new battery… For reference I live in Michigan, so it’s very cold right now, and I leave for work very early (4am). My car will sit for over 12 hours and in the morning it starts without any problems, no hesitation. But, when I get out of work 5-6 hours later, and go to start the car it still has slight hesitation/weak start up. None of the cables/terminals are loose, no lights are on on the inside. I haven’t taken the car back to have the place recheck the battery just in case, but does anyone have any idea, or has had the same experience?

I assume that you are referring to the terminal connections at the battery. Try tracing both battery cables to their other end, and you just may find a loose or corroded connection at that other end.

Do you mean it seems to be cranking – that rrr rrr rrr sound – more slowly after work than the first start in the morning? hmmm … normally I get more robust cranking in my vehicles on second and third starts of the day, simply b/c the ambient temperature is warmer and the engine has retained from heat from prior runnings. So you symptom is unusual.

It could be a loose connection at the battery posts I guess. Two pieces of metal come together there and if the outer one expanded more w/heat, that might cuase it to loosen a little when the engine compartment temperature is higher. Something worth checking. On my Corolla anyway, the connections seem to get tighter with higher engine compartment temperature, so I doubt that is the explanation.

Here’s my guess. The heat of the exhaust system is somehow adversely affecting the starter motor. On some vehicles there’s a heat shield to protect the starter motor from the hot exhaust system for this very reason. Maybe you’re supposed to have one, but it fell off. Or a tech who was working on the car prior took it off to do the repair, then didn’t install it again, thinking that part had no obvious purpose and was just getting in the way.