Mercedes W169 A150 serpentine belt squeak diagnosis
Is it the belt, or a bearing? In this case, it's the belt. The principle here is I am squirting a small amount of water onto the serpentine belt as it runs around the water pump pulley. the squeak in this video isn't very pronounced, but I could hear that it disappeared as soon as I managed to get water into the right place and came back as the water dried off the belt. After looking around online, there's very little information on these little cars, but they are very similar mechanically to the W168 that came before. This simple test shows that I'm not looking at a failing tensioner or idler pulley bearing in this case. The back of the belt (smooth side) is shiny, which has been described in a few places as a sign it's ready for replacement. The mileage on my car is just over 65,000 and there's no belt slip, so I will just order a belt and replace it.
Is it the belt, or a bearing? In this case, it's the belt. The principle here is I am squirting a small amount of water onto the serpentine belt as it runs around the water pump pulley. the squeak in this video isn't very pronounced, but I could hear that it disappeared as soon as I managed to get water into the right place and came back as the water dried off the belt. After looking around online, there's very little information on these little cars, but they are very similar mechanically to the W168 that came before. This simple test shows that I'm not looking at a failing tensioner or idler pulley bearing in this case. The back of the belt (smooth side) is shiny, which has been described in a few places as a sign it's ready for replacement. The mileage on my car is just over 65,000 and there's no belt slip, so I will just order a belt and replace it.