Need input on weird engine sound

[illmatic37]

Tonight I started my 6, I finally have the time to try and get her up to speed and back on the road again. I put the battery back in the car, it was dead, used a jump pack to start it. When idling its making a weird noise that I can only describe as sounding like a cross between a duck honking and a horn. ( musical instrument kind of horn like a trumpet/oboe, not car horn). My first thought was maybe a pulley or bearing, but it's not a high pitched squeal. When my idler pulley on my 3 series went bad it had a totally different sound. Sounds like it's coming from the front of the motor, around the fan area. The sound is not high pitched, more of a lower droning tone, speeds up with increase in throttle which leads me to think it might be accessory related? Would a bad alternator or water pump or compressor make that kind of sound? I have enough experience and tools to fix/repair things, but a lack of experience/knowledge in diagnosing.

Background on the car, '89 635, 33,xxx miles, auto trans. I am the second owner, to my knowledge everything under the hood is factory original with the exception of the oil filter. The car had sat for years and years and years at a time, garaged by the previous owner, I've had it for about 8 or so years, also sitting for the majority of the year. The last time I drove it was about a year and a half ago, it ran well as it always has, tonight however was a different story. Also coolant light is illuminated on the control panel, will check the level tomorrow, also "check" is flashing on the dash. Never saw that illuminated before.

if anyone can advise as to what to check, or if they have any experience with what I'm describing I'd appreciate a lot.

[Dschart]

Sounds accessory related. Remove the fan from the engine and run it again to see if that's it. I've had viscous fan clutch sound like that. It's a 32mm nut on the front of the water pump, and Left Hand thread. I take the 2 upper rad bolts -10 mm socket- pull the rubbers off those 2 mounts. Push the radiator forward when removing that fan. I damaged a core once, and am very carefull sliding that fan off once the LH thread is backed away from the WP drive.

The other thing that comes to mind is the belt alignment and alternator mount bushings. If the fan does not resolve, take the alternator belt off the engine and run it again...not too long...because WP won't be feeding JW.

Anyhow....isolate 1 thing at a time and pinpoint the culprit.

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[Dschart]

Sorry, 1st priority, make sure the coolant - Jacket Water, is full and burped. There is an 8mm needle valve on top of the T-stat housing to burp the system when filling JW.

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[EuroGeorge]

Make sure coolant is topped. Worn alt bushings can allow the alternator to shift "sideways" making a strange sound. Check the belts for tightness. Fan clutch, water pump can make some strange noises when they go south. If it's from drivers front, could be power steering pump. If its from passengers side front could be a/c compressor.

[illmatic37]

Thank you Dschart and EuroGeorge for the input. Today after I washed it, it was super dusty from sitting, I started it again, the noise is still there, it's less loud now, but the noise changes (getting louder and softer) as I turn the steering wheel. As such I suspect the power steering pump. Are the power steering and brake systems connected? Last night when I moved the car I noticed that the first initial few presses of the brake pedal were very easy, but after moving the car from its parking space to wash and back, the brakes feel normal again. I've done some research, it seems my next step would be to change the filter in the PS reservoir and see if it remedies the noise?
Are the PS and braking systems connected, and if so if I drain and refill the PS reservoir would I need to bleed the brake system?

Sounds accessory related. Remove the fan from the engine and run it again to see if that's it. I've had viscous fan clutch sound like that. It's a 32mm nut on the front of the water pump, and Left Hand thread. I take the 2 upper rad bolts -10 mm socket- pull the rubbers off those 2 mounts. Push the radiator forward when removing that fan. I damaged a core once, and am very carefull sliding that fan off once the LH thread is backed away from the WP drive.

The other thing that comes to mind is the belt alignment and alternator mount bushings. If the fan does not resolve, take the alternator belt off the engine and run it again...not too long...because WP won't be feeding JW.

Anyhow....isolate 1 thing at a time and pinpoint the culprit.

Sent from my SM-G900V using Tapatalk

Make sure coolant is topped. Worn alt bushings can allow the alternator to shift "sideways" making a strange sound. Check the belts for tightness. Fan clutch, water pump can make some strange noises when they go south. If it's from drivers front, could be power steering pump. If its from passengers side front could be a/c compressor.

[Dschart]

The brake fluid and power steering fluid are separate. The power steering fluid does power the brakes...Hydro assisted power brakes. There is an accumulator " brake bomb" and a hydraulic assist on the master brake cylinder. The brake fluid does not need to be blead if you are servicing the power steering system.

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[bmw6fan]

The check light is on because of the coolant light. It should clear when you clear the coolant light. Check the power steering fluid level. If low fill and bleed by turning wheels full left and right a few times.

[Sprocket]

This is where a stethoscope would help. I don't use mine often, but it would at least isolate the source pretty closely.

[illmatic37]

Thanks for the responses guys, I'll check the PS level this week. I've read dextron 2 or 3 should be used. Is one preferred over the other?

[bmw6fan]

I use 3 only because it's usually easier to find.