High-pitched, Hydraulic Whine
 

Driving the Chevy Express today and when I came to a stop at a stop light, I heard a high-pitched, hydraulic-pump like whine coming from the front of the vehicle. I had had the transmissions fluid replaced a week ago (preventative--it was a used rental when I bought it). I became concerned that something might be going with the transmission. But the sound clearly sounded more like a power steering pump whining.

On the way home I grabbed lunch for the family at a drive thru, and I found that the sound went away when I put it in park. Did taking a load off the engine have something to do with it? Even stranger, I found the sound returned when I shifted into neutral (either from drive or park).

I got home and got to investigating. I had my wife help as I needed someone to shift it to drive and keep their foot on the brake. She put it in drive and I immediately heard the whine but I couldn't place it. I got out my mechanic's stethoscope and checked the power steering pump. Nope. I checked the brake booster. Nope. I checked the engine block. Lots of noise, but no whine.

Then I found it....

The driver's side headlight! I had put cheap, $10 LED bulbs in a year ago. The one on the drivers side was not lighting but the fan on the back was making the whining noise. I was actually really happy with the performance of the headlights, but I'm not surprised that they failed so quickly given the price point. I had actually ordered two sets so I removed the year-old set and replaced them with the new ones. I'll order another set of nicer ones for when these fail.

Well, I would have never guessed that one .

Try replacing the blinker fluid next... ;)

I most likely would not have heard it. High frequency doesn't exist to me anymore...

Interesting find though.

I put LED headlight bulbs in my wife's Odyessey and when the car is in the garage, key on but not running and headlights on I can hear a whirring noise from the fans on the bulbs. Can't hear it when the engine is running but that may just be one of the benefits of being half deaf.

Now that you mention it, there are aftermarket LED's in our Denali, and likewise, they make noise . You could never hear it with the engine running , or even from inside the cabin, but outside of the vehicle, there is a dull humm. I just had to replace one of the chineesium ballasts ., and remember hearing that when I was trying to diagnose it.

Wait.....headlights have fans now?

When replacing the standard headlight bulb with LED, they often have a little cooling fan attached...

http://forums.pelicanparts.com/uploa...1609104234.jpg

WOW.

TF kind of headlights are those?

rjp

Yep, I have some of those in my truck, makes it much safer to drive and I have never had anyone flash their lights at me.

Well not exactly like that, but similar. Mine were not that cheap.

Of course I can't hear squat over the PowerStroke.

Nice fine. I have an occasional whine from the passenger seat area... there are times it’ll continue even after I shut off the ignition.

I was going to guess bad pulley, take the belt off engine run for a few seconds and if sound goes away it's one of the pulley bearings or something else the serpentine belt rotates.

Headlight light bulb?

New one to me.

None of our cars use LED - yet.

late last night as i was taking out the trash i heard a whine coming from the rear of the Subaru. We used it earlier to do some errands. Engine was off. Been off for about 7 hours. This morning i decided to find out what the hell was going on. Turns out they have an auto fuel evaporating leakage checking system that runs for @ 15min. 5-10 hours after the engine is shut off. Never heard of such a thing, but it's in the owners manual. Some GM vehicles do the same.