I need some help from the mechanical experts on the board. I am an Electrical Engineer by trade so if it doesn't envolve electrons I am lost.

During my most recent oil change the Stealership told me I need to have my engine belts replaced. I read on the board that some moderate cracking is ok in the belts. What symptoms will the car exhibit if my belts are going bad i.e. squeeling, slow acceleration, etc. ?

I have attached a picture of one of the belts where I can see the ribs.

If I do need new belts are there aftermarket belts which last longer? Where can I purchase OEM belts online. I tried everythingg35.com but they did not have any

 

Believe 50-60K is the suggested interval, but yeah...I'm seeing cracks in your pix. Probably good idea to replace. Non Nissan belts are fine or if you still want oem go here:
http://www.riversideinfiniti.com/j/i...LineParts.html

 

50-60K is the right interval. I'm goin to change mine this week. Don't go to the stealership. Coz when i asked them they told me it will cost $280 to change it...

 

its time for my belts to change also...any suggestions on which belts to use...i dont mind buying oem belts if aftermarket belts will be squeaky etc

 

Definitely change them yourself if you can. $280 to change belts is ridiculous. The belts themselves will cost you less than $40 and as long as you can follow directions and use basic tools you can do it yourself. Here's a great write up to use

https://g35driver.com/forums/engine-drivetrain-forced-induction-diy/117355-diy-power-steering-alternator-air-conditioning-belt-change.html