I wanna say clean but I just wanna hear what the forum has to say...

G37 start up:

 

Belts can't be cleaned unless you know something got on it. Depending on your miles it would need to be changed or just need to be re tighten.

 

48K ... so spraying belt conditioner wouldn't help? i don't notice any cracks in the belt and i think a drop of oil dropped on it whilst checking oil... and the belt doesn't have any play in it. it's still stiff.

 

You can clean a belt if you have something on it. You can use belt conditioner. However before even considering that make sure the belt is in 100% condition and is properly tightened. If its glazed, brittle, frayed, or has tiny cracks in the ribbed side, or worn in any other way go ahead and change it out.

 

Give thx black betty

 

That sounds weird, sure its the belt?

Why do older G37s start up so weak? Mine (08 G37) starts up the same even after I changed the battery?

 

That's what I suspect because I only hear the squealing at the startup. Never again until the car has cooled down. I'll change it the belt. Did some research and belt conditioner doesn't do serpentine belts any justice. ..

I read somewhere that the alternator clutch doesn't kick in until after 8 miles or a periodic time frame. ..

 

Maybe the tensioner?

Found a DIY on how to change the serpentine belt

https://www.myg37.com/forums/d-i-y-i...an-09-g37.html