* Incorrect tensioner installation: The most likely culprit is that the new tensioner wasn't installed correctly. This could mean it's not providing the right amount of tension, or there's some interference preventing proper function. A slightly misaligned tensioner pulley can cause uneven belt wear and breakage.
* Defective tensioner: While less likely if it's a new part, it's possible the replacement tensioner is faulty. It might be failing internally, not providing consistent tension, or the pulley itself is defective.
* Worn or damaged pulleys: The AC compressor pulley, crankshaft pulley, or alternator pulley could be damaged (grooved, out of round, or seized). A damaged pulley will cause the belt to slip and eventually break. Inspect these pulleys carefully for wear and tear.
* Seized AC compressor: A seized AC compressor will put excessive strain on the belt, leading to breakage. Try to manually rotate the compressor pulley – it should turn freely. If it's difficult or impossible to turn, the compressor is likely seized.
* Bent or misaligned components: Something might be out of alignment, forcing the belt to run at an angle or rub against other parts. This could be a misaligned engine mount, a bent bracket, or even a slightly bent crankshaft pulley.
* Belt routing issues: While less common after a tensioner replacement, ensure the belt is routed correctly around all the pulleys. Incorrect routing puts uneven stress on parts of the belt, causing premature failure.
* Incorrect belt size or type: A belt that's too small, too large, or the wrong type (e.g., wrong material or construction) won't last. Double-check that the correct belt was used.
Troubleshooting Steps:
1. Visually inspect all pulleys: Look for grooves, cracks, or any signs of damage. Check for pulley wobble.
2. Check AC compressor operation: Try to rotate the compressor pulley by hand. If it's stiff or seized, the compressor needs attention.
3. Verify belt tension: Even with a new tensioner, make sure the belt tension is correct. There are usually specifications for this in your vehicle's repair manual. Use a belt tension gauge for accurate measurement.
4. Inspect the belt routing: Make sure the belt follows the correct path around all pulleys.
5. Check for alignment issues: Look for anything that could be causing misalignment.
If you're not comfortable performing these checks yourself, it's best to take your Silverado to a qualified mechanic. They have the tools and expertise to diagnose the problem accurately and perform the necessary repairs. Simply replacing the belt repeatedly without addressing the underlying cause is a waste of time and money.
