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DISCUSSION => General Topics => Topic started by: BJMW on April 30, 2014, 10:36:20 PM

Title: '91 318is high pitch sound
Post by: BJMW on April 30, 2014, 10:36:20 PM

I just bought my second car, a '91 318is. My other is an '89 325i.  The 318 is great. It's smooth, light and nimble.  The car runs perfectly fine, but it makes a high pitch noise with rpms. I almost want to say its a whine but it may just be how it's supposed to sound. It's not terribly loud but I wanted to know, is something wearing? Or Do the 318's just have a higher pitch sounding engine compared to the 325 m20 engines?

Thanks,
Brian

Title: Re: '91 318is high pitch sound
Post by: Slowered318 on May 01, 2014, 06:52:20 AM

Sounds like you got lucky with this 318 if you can describe it as "smooth". I found m20's to be very smooth compared to m42's but the valve train could get noisy if not maintained and the motors have a distinctive "woosh" sound to them.

As for the m42, the timing chain guides and injectors can get a little noisy but the exhaust note is not exactly high pitch. I'm thinking the noise is something aside from the motor. 318's came with a little less sound deadening so it could be the fuel pump, bad ground on the stereo, possibly a bearing along the driveline or something is lose in your exhaust.

Title: Re: '91 318is high pitch sound
Post by: keflaman on May 01, 2014, 09:46:36 AM

Quote from: BJMW on April 30, 2014, 10:36:20 PM

The car runs perfectly fine, but it makes a high pitch noise with rpms.
Thanks,
Brian

All my cars do that when my wife rides with me.

Title: Re: '91 318is high pitch sound
Post by: Slowered318 on May 01, 2014, 12:42:21 PM

Quote from: keflaman on May 01, 2014, 09:46:36 AM

All my cars do that when my wife rides with me.

Oh that noise? I find it gets loudest after I install a bunch of new parts.

Title: Re: '91 318is high pitch sound
Post by: Nick_318is on May 01, 2014, 05:08:28 PM

Quote from: keflaman on May 01, 2014, 09:46:36 AM

All my cars do that when my wife rides with me.

Mine gets louder the faster I go around corners.

OP, can you post a video or something of the sound, hard to diagnose it without a better description.  Where does it come from, the engine bay or someplace else?

Title: Re: '91 318is high pitch sound
Post by: BJMW on May 02, 2014, 02:34:18 PM

It's coming from the engine bay.  I'll keep an eye out for this "wife".  Heard it's forced some to sell.

Here's a few videos.  The video from inside the car, you can barely hear the noise so turn it up a little.  It's louder in person.

Thanks

https://vimeo.com/93646674?utm_source=email&utm_medium=clip-transcode_complete-finished-20120100&utm_campaign=7701&email_id=Y2xpcF90cmFuc2NvZGVkfGExYzVmNzY4OGRhYmVlMTRiZjg4NGY2NDM2NTJlYTIzNjQzfDI3NTkwMDM3fDEzOTkwNTYyMDJ8NzcwMQ%3D%3D

https://vimeo.com/93646763?utm_source=email&utm_medium=clip-transcode_complete-finished-20120100&utm_campaign=7701&email_id=Y2xpcF90cmFuc2NvZGVkfDI2YWNiMjE1ODZiOTE1ZTJjODlmODI3MWI2MmFmN2RhMzk4fDI3NTkwMDM3fDEzOTkwNTg1OTN8NzcwMQ%3D%3D

Title: Re: '91 318is high pitch sound
Post by: keflaman on May 02, 2014, 06:01:38 PM

I'm inclined to suggest you rule out accessories by removing the belts and see if it stops. Hold a wooden dowel or something similar up against your ear and touch different areas of the engine and see if you can locate where the noise is coming from. Definitely not coming from the front passenger seat. :)

Title: Re: '91 318is high pitch sound
Post by: 281Lew on May 04, 2014, 08:10:41 AM

My car made a high pitch noise.  It turn out to be a loose belt.