Hello. In trying to keep this simple without explaining the entire issue.
My question is: My 2018 Silverado has an idler pulley for the AC and Water pump that has an inside dimension of 17mm. There is a dust cover on the front and insert on the back of the bearing.
Can I use a new idler pulley with a 10mm inside dimension bearing instead of a 17mm factory one?

Thank you.

 

If you’re still needing an answer….

The critical points to consider when replacing a pulley are:

1) Correct outside dimension.

If it has a larger OD, the belt may be over tight or not fit at all; if it’s smaller, it may not allow for the belt to be tensioned properly.

2) Correct width.

If it’s not as wide, the belt will overhang and that will wear the edges out quickly, causing cracks or tears in the belt.

3) Correct fore/aft and left/right positioning.

The pulley needs to be in the correct position to maintain belt alignment and tension. Incorrect alignment and tension will cause noise and/or create additional load on the bearings.