RPM dependent whine, any advise?

[ME30W]

I have an automatic 89 325i. Recently I've been hearing a sight whine that becomes higher pitched as RPMs increase. It's usually drowned out by the engine noise, but at higher RPMs it becomes more audible.

My first thought was the water pump, but it only has about ~7,000 miles on it

Everything else with the car has been completely normal, so I'm not quite sure how to go about diagnosing the problem.

Any advise or help would be greatly appreciated. This might be a long shot, but if anyone who knows these cars well lives in NYC and wouldn't mind lending a helping hand I would certainly make it worth their while.

[IRON-E]

Sounds like the t-belt tensioner, but you can always visit Guten Parts Service in Jersey, for a full rundown of the mechanicals.



Good luck

[e30Rooster]

Power steering....?

Sent from my C771 using Tapatalk 2

[jlevie]

Assuming the whine is audible when the car is stationary and being rev'd, the belt driven parts can be eliminated as a cause by removing them. With the engine cold, no harm will come by running the engine briefly with the water pump belt off. If the noise isn't coming from one of the belt driven parts, the timing belt tensioner pulley is the next most likely cause. After that it could be from the transmission.

[ME30W]

Assuming the whine is audible when the car is stationary and being rev'd, the belt driven parts can be eliminated as a cause by removing them. With the engine cold, no harm will come by running the engine briefly with the water pump belt off. If the noise isn't coming from one of the belt driven parts, the timing belt tensioner pulley is the next most likely cause. After that it could be from the transmission.

I don't seem to hear anything when the car is in neutral and I rev it. I'd love to take it to Guten for a look-over, but I called them earlier in the month and was told they have no open appointments until the middle of the summer!

[dnguyen1963]

Don't forget to check your alternator. Degenerating alternator can make whining noise.

[ME30W]

Don't forget to check your alternator. Degenerating alternator can make whining noise.

I just took a quick drive to listen a little closer to the sound, and it seems that it is more of a hum, kind of like an electric motor noise, that gets higher pitched as RPMs increase.

Would this then exclude the timing belt tensioner? I'm thinking its the alternator now, but maybe someone can help clarify the situation for me

[slammin.e28]

It's not coming from your speakers is it?

You heard it outside of the car?

[ME30W]

It's not coming from your speakers is it?

You heard it outside of the car?

definitely not coming through the speakers, I can hear it inside the cabin while driving

[dnguyen1963]

Use a long screw driver (if you do not have a stethoscope) and place it on the alternator housing and other suspected locations. Listen to it with a friend revving the engine. You can isolate the sound better.

[ME30W]

Use a long screw driver (if you do not have a stethoscope) and place it on the alternator housing and other suspected locations. Listen to it with a friend revving the engine. You can isolate the sound better.

Thanks! I'm planning on getting that done tonight, other than the waterpump, and alternator is there anywhere else that I should pay close attention to?

[dnguyen1963]

Thanks! I'm planning on getting that done tonight, other than the waterpump, and alternator is there anywhere else that I should pay close attention to?

Timing belt area...listen for the tensioner.

[hamilton325i]

I would try to get an ear on anything that has a crank driven pulley if it were me. You can also quickly rule out individual belts by giving each one a small burst of brake clean and see if the noise goes away.