2005 Porsche 911

On cold starts the engine makes a continual squeal. Within minutes if I drive it or simply rev the engine a few times the sound is gone and the engine again sounds glorious. If I spray the belt with water the sound immediately ends. I have replaced the water pump, belt tensioner roller, idler rollers and of course the belt. All to no avail. I’ve run out of ideas. Any suggestions?

You might have a component with bearings that are failing and loading down the belt. You should check for his with the belt removed. Failing bearings can be felt as excess force required to turn and often as lateral play in the pulley.

By the way, I just noticed you said you changed the “belt tensioner roller”… did you check the belt tension? The tensioner might be getting weak.

One of the accessories is probable causing it to slip. Try turning the wheel a little while it’s squealing. If it changes pitch than power steering pump is the likely cause. You could remove the belt and turn each while they are cold and listen for bearing noise.

Sounds like you’ve done what is logical, now why not go a little further? Start the engine and go back and open the lid and listen while someone is turning on/off accessories, lights, AC, stepping on the brakes, turning the steering wheel, and so forth. I think that the other folks who have posted have put you in the correct direction. Now try to eliminate what is causing your belt to slip, gotta be something. Good luck! Rocketman

Make very sure that it’s not just coincidence that the squeal stops when you spray it with water. Those engines were prone to intermediate shaft bearing grease seal failure which can cause the bearing to lose its lubricating grease, which then makes a squeal that mimics a slipping serpentine belt, shortly before the bearing fails and destroys the whole engine. There is a retrofit kit available to replace the improperly-designed sealed bearing with an open one that uses engine oil as lubrication rather than grease.