The case of the mysterious squeal... e90 330d... solved

matt_s · 09-07-2019, 05:32 AM

Hello just thought I’d post in here regarding my mysterious squeal... e90 330d with m57 engine
About two years ago, I replaced the belts, pulleys and tensioner. Shortly after that, started getting a squeal in start up, and then more recently a rotational squeal which varied with speed, and went away when the engine was warm.
In the original maintenance activity, I used BMW genuine tensioner and pulley, a Gates ac belt and a Dayco belt from ECP.
When this squeal started, I thought “it can’t be anything I’ve just replaced as it’s all new, it must be another pulley/alternator, right?” Wrong.
Fast forward two years, 1 child later and I’ve had enough of the squeal, quite frankly it’s embarrassing every time I start the engine and it’s getting on my nerves. Read a few forum posts on here. Fan out, belts off, replace the dayco (lowest priced part)... replaced with a more expensive continental conti tech serpentine belt.
Nervously start the engine... no noise. Fixed. The dayco belt is smooth on the back side, the continental belt is rubberised/grippy on the back.
Morale of the story, buy cheap, buy twice. Sure I’ve read that in this forum before...
M

09-07-2019, 05:32 AM	#1
matt_s Private 15 Rep 55 Posts Drives: 330d e90 Join Date: Jul 2012 Location: Costa del Sheffield iTrader: (0)	The case of the mysterious squeal... e90 330d... solved Hello just thought I’d post in here regarding my mysterious squeal... e90 330d with m57 engine About two years ago, I replaced the belts, pulleys and tensioner. Shortly after that, started getting a squeal in start up, and then more recently a rotational squeal which varied with speed, and went away when the engine was warm. In the original maintenance activity, I used BMW genuine tensioner and pulley, a Gates ac belt and a Dayco belt from ECP. When this squeal started, I thought “it can’t be anything I’ve just replaced as it’s all new, it must be another pulley/alternator, right?” Wrong. Fast forward two years, 1 child later and I’ve had enough of the squeal, quite frankly it’s embarrassing every time I start the engine and it’s getting on my nerves. Read a few forum posts on here. Fan out, belts off, replace the dayco (lowest priced part)... replaced with a more expensive continental conti tech serpentine belt. Nervously start the engine... no noise. Fixed. The dayco belt is smooth on the back side, the continental belt is rubberised/grippy on the back. Morale of the story, buy cheap, buy twice. Sure I’ve read that in this forum before... M
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