GMC Terrain Belt Tensioner Troubles & Repair Tips

I had a similar issue with my 2018 GMC Acadia, as someone with some experience working on cars, I recognized those belt squealing symptoms right away. The belt tensioner was indeed the problem, causing issues with the entire serpentine belt system. My idler pulley was showing signs of wear which affected engine performance pretty significantly. I took it to my regular workshop where they diagnosed a defective belt tensioner assembly. The repair process involved replacing both the tensioner and related components to ensure proper automobile maintenance. The total cost came to 455 Euro including parts and labor. The repair wasn't overly complex, they had it done in about 3 hours. Since the fix, the engine has been running smoothly with no more squealing or irregular noises. To better assist with your situation, could you provide: Current mileage on your Terrain, When you first noticed the symptoms, Whether youve had any recent belt or pulley work done, If youve noticed any changes in engine performance besides the noise This information would help determine if youre dealing with the same issue I experienced and whether there might be related components that need checking.

Last service was done 3 months ago at 85000 km. The engine performance has definitely declined since then, especially when accelerating. I checked under the hood and noticed the belt tensioner seems loose, causing the timing belt to make that awful squealing sound. The engine noise gets worse during cold starts and when turning the steering wheel fully. Given my current mileage of 88198 km, I am wondering if this could be related to routine automobile maintenance that was perhaps overlooked during the last service. The belt tensioner assembly might need complete replacement rather than just an adjustment. Thanks for sharing your experience, the repair cost and timeframe helps set my expectations. I will schedule an appointment to have it properly diagnosed.

Thanks for providing those details about your Terrain. Your symptoms match exactly what I experienced with my Acadia before the repair, especially that intensified noise during cold starts and steering. Based on the mileage you mentioned, timing is about right for a serpentine belt system overhaul. In my case, the entire belt tensioner assembly needed replacement because simple adjustments wouldnt fix the underlying wear. The technician also noticed the serpentine belt had developed small cracks, which contributed to poor engine performance. One thing I forgot to mention from my repair, they also checked the water pump pulley since it can cause similar symptoms when failing. With your mileage, it might be worth having them inspect that component too while they have the belt system apart. After my repair, the engine noise completely disappeared and power delivery became much smoother. The belt handover function also started working perfectly again once the new tensioner was properly calibrated. Would recommend getting it checked soon before the worn tensioner potentially causes damage to other components in the belt drive system.

The symptoms you described match my situation perfectly. Those cold start noises and steering-related squeals were exactly what I experienced. Good to know I'm not alone in dealing with this. My mileage reading of 88198 km definitely suggests it could be time for a complete serpentine belt system service. The fact that the belt tensioner is visibly loose and causing timing belt noise is concerning. I appreciate the heads-up about checking the water pump pulley, will definitely have them inspect that too. I will book an appointment right away since I dont want to risk further damage to other components. The 455 Euro repair cost you mentioned seems reasonable for the work involved. The 3-hour timeframe also helps me plan my day when I take it in. Really appreciate the detailed information about your repair experience. It gives me confidence that replacing the belt tensioner assembly should resolve these issues and restore proper engine performance. Will update once I get it fixed.