e34 chassis noise troubleshooting

[mc625569]

I'm at a bit of a loss trying to troubleshoot a loud squeaking noise on my e34. I don't expect a vague post like this to reveal some type of a-ha moment, but I'm looking for advice on how to approach troubleshooting with home mechanic tools.


Intermittent sqeak happens starting at about 45mph , loudest from inside the car in passenger footwell.

it sounds like its coming from right behind the glovebox. I tried some silicone spray on the control arm and stabilizer bar bushings but no real imapct.

It does not sound like a typical wheel bearing grind. I've recently replaced the shocks and subframe bushings and this didn't seem to change the noise at all.
Does not sound like a wheel bearing grind.

I'd chalk this up to a bushing on one of the suspension parts, but It only seems to happen at speed which is what's throwing me off.

Are there any tips/tricks/tools I can use to try and narrow this down, its hard since I can only replicate the noise at highway speeds.

I've been looking into some type of home brew chassis ear type device but figured I'd post here first for suggestions.

[roguetoaster]

Split it in to rotational, abrading, or vibration noises. Isolate the cause, engine RPM, speed, pavement, temperature.

[AndrewBird]

Brake pad dragging on the rotor maybe?

[marshallnoise]

I am willing to bet its the blower motor for the HVAC. Next time you hear that, turn the fan off and see if it goes away.

[mc625569]

Wanted to update. Thank you everyone for the suggestions. I tore the car apart and ended up having to get a hold of a steelman chassis ear unit. The loud noise is coming from something in the sunroof.. the noise was projecting from the footwell but when I put the sensors all around the car I eventually narrowed it down and once I took the headliner off that confirmed it. I think I’m only hearing it at speed because that’s when the car is getting the most wind blowing over the sunroof. I literally tore out the dash and replaced a ton of suspension parts playing “shotgun” part replacer and finally found it. Side note : I now have a steelman chassis ear that I’m thinking of renting out to recoup some costs. Again, thank you for replies - each one helped me continue to narrow down options. Sent from my iPhone using Tapatalk