M60 V8 - Strange noise

[Frank87]

So I am rounding up the few remaining technical jobs on the E34. Once these are complete, it will get a full respray and body rebuild.

My last technical issue, is a strange low pitched whining noise from the engine bay that has been there since I bought the car. The noise sounds like a pump or bearing, anything that spins. Some info on the noise:
- Noise there when accelerating between 600 RPM idle and about 1.500 RPM
- Noise when decellerating and going under 1.500
- Noise sounds like a tired object, it doesnt sound constant like a bearing failing "whoooooooooooooooooooooooooosh" but more like "whooOOOhoooOooooOHoooosh"

I cant film or record it as I can not reproduce it when the car is running idle. Even when I play with the throttle body. However, right after firing up the car, the noise is there for about a second.


Alot of items can be excluded:
- Waterpump, belts, tensioners, idlers all replaced. Belt not too tight. Checked by my capable indy.
- PCV valve replaced
- Autobox and torque converter replaced


I am now making a list of items that can cause noise. So far I have:
- Fan clutch? (Replaced after buying the car but used aftermarket brand)
- Alternator (about to be replaced by one I rebuilt myself)
- Steering pump
- A/C compressor (I am taking off the belt tonight to drive for a week without the A/C on the belt system)
- Any ASC item? I think I have the vacuum operated ASC
- Brake booster? Can this object produce noise?
- Vacuum control system, where can I find its air pump? (saw this on realoem: http://www.realoem.com/bmw/enUS/show...diagId=11_4953)


My car should not have the pierburg secondary air pump as it is a 12/93. Where can I find this pump? To check if I have it..

The steering box itself does not make noise does it? Would be the pump if it was steering related right?


If anyone has any other suggestion of parts that I can exclude, let me know. I want to have this fixed as I am nearing technical perfection on this car. Oil consumption is about 1 liter per 10.000 kilometer, perfect idle, fuel consumption steady at 10/100, just fitted 4 ATE PowerDisc brake rotors+pads and my home-rebuild gearbox shifts excellent. Gotta nail this noise thing.

[whiskychaser]

As you can't replicate it when you are under the bonnet, a wild stab in the dark - could it be your heater fan or the fan in the heater control unit?

[Frank87]

Forgot to mention this:

Week back I was under the car and someone on the lift started the car. I heard the noise for about 2 seconds and it came from the front of the engine. So anywhere behind the head lamps but in front of the last 4 cilinders, this is the target area where the noise came from.

It is definately coming from the engnie bay.

[632 Regal]

Power steering pump can make that sound. It could be low, should be about 1 inch from the top. If you have the incorrect fluid it can also make noise.

[Frank87]

In theory, I have the incorrect fluid. I should use Pentasin but I am using DIII as it is cheaper. Since I dont have SLS, the Pentasin is not needed for SLS. I have seen people switching to DIII on LuK pumps often without any trouble. Also on E39 and E38 models without sls. Even when I bought the car, there was already DIII in the system.

I just saw 2 hoses in the low pressure area of the steering system that are a little wet and have crappy old hose clamps. I am going to replace those hoses and use new hose clamps. If, for some reason, the system sometimes sucks in a little air, that would explain noise from the pump. Fluid level was never below minimum. I check oil, brake, coolant and steering system each month.

[genphreak]

DIII as it is cheaper. (than what, CHF 7.1)? Just use Pentosin CHF11S- or pretty much any green synthetic transmission fluid. Synthetic trans fluid is barely more than Dexron and will not break down.

Make sure the noise is not an idler or tensioner pulley- I replace these (and the serpentine belts) on all my cars fairly promptly after buying, as it keeps them quieter and they will fail at some point otherwise.

[Clarksonvalley]

Try removing the radiator fan. It has a left hand thread. My 540i makes the same sound and I'm pretty sure the noise is coming from the fan. Let me know the results of the fan removal.

[bennyg]

I bought my 5/93 540i with dex3 in the PS reservoir (owner went f*k-it-cheap-a$$ on negotiated fixes for the rwc). Had it flushed straight away but a flush only gets 3/4 of the fluid apparently. I read somewhere dex3 eats the seals in the Pentosin system. Whether or not that's true, a year later issues with both a leaky ASC and now another year on a whine I'm sure is related to a PS leak that causes my steering to lock under heavy acceleration. I have not had any spare time to do anything about it yet though but hope to soon.

Sent from my GT-I9305 using Tapatalk

[Clarksonvalley]

My 540i whines in 1st gear when it is first started and also when it has warmed up, but then quiets down after about 2000 RPM, but the whine is always there at low RPM. I use Prestone Power Steering fluid. I also have replaced the power steering lines with 'Earl's Superstock' hose from the cooler to pump and reservoir to cooler using 'Earls' threaded fittings. I also brazed threaded fittings onto the cooler tubing - the hose replacement eliminated the leaks I've had for years, but had nothing to do with the whining - just wanted to get rid of the leaks. Anyway, if you think the whine is from the PS pump, remove the serpentine belt and start the engine briefly - removing the belt will also take the alternator and water pump out of operation. Or, remove all of the belts and run the engine briefly. One of the belt driven accessories is causing the whine. Let me know how it turns out.

[Frank87]

Replacing all PS hoses this saturday. I also have some leaky lines in the low perssure area. Now that its cold, the sound is gone so Ill have to wait till spring.