Flat spring or coil spring belt tensioners?

[05ChevyI5]

Either are $40-60 bucks for my pickup. I did notice the Gates torsion coil-spring tensioner has a lifetime warranty. A Dayco for example has a 12k mile warranty.

 

[Rand]

warranty doesnt nec. mean much... look how many lifetime brake pads are total poop.

 

[Trav]

Coil spring types are more durable and hold tension longer in my experience.

 

[Schmoe]

Coil

 

[05ChevyI5]

Originally Posted By: Trav
Coil spring types are more durable and hold tension longer in my experience.

What makes these rattle at low rpm's? Pully bearings or weak springs?

 

[Trav]

Usually pulley bearings. A weak spring will cause the belt to slip and wear quickly but rarely is the source of noises unless it has a broken spring, it can cause belt squeal.
If you remove the belt you can check the pulley bearing easily by spinning it, its its not smooth and silent its gone. It can be replaced without the whole unit.

 

[05ChevyI5]

Mine will rattle at idle like a small diesel more so when cold, but it's quiet above 1500 rpms. I'm going to change the entire unit since it's oem and 9 years old. Surprisingly the oem Dayco belt is in excellent shape.

 

[05ChevyI5]

I replaced the tensioner today and all's well. The spring body was starting to separate and slightly canted the pulley bolt in contact with a engine block casting protrusion in the pulley area, more so at lower rpm's.