Strange Electronic Noise near radiator when car sitting off & other unusual noise

sf70h · 12-19-2017, 08:51 PM

Just thought to post here in case anyone has any insights as to what this could be.

After driving home, parked as normal went inside ate dinner. Was lurking in the garage afterwards and instantly noticed a loud electronic hum coming from the car (car was completely off - no headlights on, no map light left on etc..). After investigating it some, I popped the hood it seemed to be coming from inside the engine compartment near the nose of the car or radiator area. Really high frequency, but loud electronic noise - similar to if you hold your ear up to a florescent lamp or something but this was loud enough where you heard it about anywhere in the garage. Again, the headlights were completely off. After I opened the driver's door to pop the hood, the sound transitioned to a louder hum and kind of a "pop" noise every 5 seconds or so then would repeat. This is from the radiator (same) area in the front of the car that the huming was coming from originally. I couldn't isolate where in the front but it seemed like it was lower in the engine bay, not anywhere I could isolate from the top of the engine bay - but could tell it was coming from the front.

I decided to go ahead and start the car, what's interesting is the radiator fan after starting the car went to full blast for about a minute then cut off (maybe that is the standard start sequence, but I don't recall that ever happening before). The radiator fan cut off after about a minute (it was definitely cranking at max speed from what I could tell and the noise), and I let it sit and run a few more minutes then shut it off. The noise is completely gone now. Strange but thought to post it.

Another unusual noise I noticed this morning was when I got into the driver's seat before starting the car I noticed what sounded like liquid sloshing/pumping from the right side of the car. It happened for about 10-20 seconds and stopped. This is just me sitting in the car before starting it or touching the start button and just the interior lighting on after I unlocked the car. It was a little alarming. I am assuming that is oil or fuel being moved around? The gas tank is about 3/4 full and oil levels are good. I checked temps in the Performance section of the display and everything looks good as well during a 15 mile ride.

KLR ZL1 · 12-21-2017, 06:54 PM

I too have heard the high pitch noise in the engine compartment. Mostly when I am cleaning the car with the hood open. I'm sure it is normal. I also hear noises under the dash when first sitting in the car too. Almost like systems are starting up. Figured it is mormal too.

Gunkk · 12-21-2017, 07:08 PM

It’s onstar uploading all your telemetry.

To stop this you have to wrap the car in tinfoil.

slick3 · 12-22-2017, 10:08 AM

Thought I was crazy. I have heard it before a couple of times. Assumed my tinnitus was acting up again LOL

Jamaison · 02-04-2019, 07:25 PM

I just started hearing this on my 2016 2SS -- exact same scenario you described: came home from work, went in the house for 45 min or so, came back to the garage and could hear it coming from front end of car. I thought I was losing my damn mind. It's been doing that off and on for a few weeks now. So has yours ever returned?

jcor3 · 02-08-2019, 08:59 AM

My 2018 SS does it all the time. I thought the neighbors had their golf cart set to reverse in their garage until I figured out it was my car, lol.

sadpanda · 02-09-2019, 10:06 AM

Try walking out without the key fob... BCM wakes up all kinds stuff when key fob is detected. Trying the door handle without the keyfob should trigger some noises as well. Some 'after run' is normal for cooling fans etc.

protovack · 02-11-2019, 10:23 AM

I think this might have something to do with the HID headlights, I'm not sure though.

geaux_tigerss · 02-11-2019, 01:34 PM

Quote:

Originally Posted by sadpanda

Try walking out without the key fob... BCM wakes up all kinds stuff when key fob is detected. Trying the door handle without the keyfob should trigger some noises as well. Some 'after run' is normal for cooling fans etc.

Huh, makes me wonder. My fob stays in my car most of the time. We have to leave the keys in our vehicles when we part where I work, and when I'm at home it's in my garage. Wonder if the BCM stays awake all the time.

Jamaison · 02-25-2019, 07:07 PM

I managed to catch mine on video around the :20 and 1:14 marks. https://youtu.be/X_4Xgi4P7N8

Gunkk · 02-25-2019, 07:17 PM

Quote:

Originally Posted by Jamaison

I managed to catch mine on video around the :20 and 1:14 marks. https://youtu.be/X_4Xgi4P7N8

sounds a lot like the hvac bleed down noise posted by some folks last summer.

12-19-2017, 08:51 PM	#1
sf70h Drives: 17' 2SS Camaro A8 Vert NPP Join Date: May 2017 Location: Virginia Posts: 43	Strange Electronic Noise near radiator when car sitting off & other unusual noise Just thought to post here in case anyone has any insights as to what this could be. After driving home, parked as normal went inside ate dinner. Was lurking in the garage afterwards and instantly noticed a loud electronic hum coming from the car (car was completely off - no headlights on, no map light left on etc..). After investigating it some, I popped the hood it seemed to be coming from inside the engine compartment near the nose of the car or radiator area. Really high frequency, but loud electronic noise - similar to if you hold your ear up to a florescent lamp or something but this was loud enough where you heard it about anywhere in the garage. Again, the headlights were completely off. After I opened the driver's door to pop the hood, the sound transitioned to a louder hum and kind of a "pop" noise every 5 seconds or so then would repeat. This is from the radiator (same) area in the front of the car that the huming was coming from originally. I couldn't isolate where in the front but it seemed like it was lower in the engine bay, not anywhere I could isolate from the top of the engine bay - but could tell it was coming from the front. I decided to go ahead and start the car, what's interesting is the radiator fan after starting the car went to full blast for about a minute then cut off (maybe that is the standard start sequence, but I don't recall that ever happening before). The radiator fan cut off after about a minute (it was definitely cranking at max speed from what I could tell and the noise), and I let it sit and run a few more minutes then shut it off. The noise is completely gone now. Strange but thought to post it. Another unusual noise I noticed this morning was when I got into the driver's seat before starting the car I noticed what sounded like liquid sloshing/pumping from the right side of the car. It happened for about 10-20 seconds and stopped. This is just me sitting in the car before starting it or touching the start button and just the interior lighting on after I unlocked the car. It was a little alarming. I am assuming that is oil or fuel being moved around? The gas tank is about 3/4 full and oil levels are good. I checked temps in the Performance section of the display and everything looks good as well during a 15 mile ride. Last edited by sf70h; 12-19-2017 at 08:56 PM. Reason: More detail

12-21-2017, 06:54 PM	#2
KLR ZL1 H-Town Camaro Club Member Drives: 17 Hyper Blue Metallic KLR-ZL1 Join Date: May 2009 Location: Pearland Tx. Posts: 2,035 View My Garage	I too have heard the high pitch noise in the engine compartment. Mostly when I am cleaning the car with the hood open. I'm sure it is normal. I also hear noises under the dash when first sitting in the car too. Almost like systems are starting up. Figured it is mormal too. __________________

12-21-2017, 07:08 PM	#3
Gunkk Thank you Al Oppenheiser! Drives: Red Hot A10 ZL1 Convertible Join Date: Jun 2017 Location: Sarasota, FL Posts: 4,975 View My Garage	Really, honest! It’s onstar uploading all your telemetry. To stop this you have to wrap the car in tinfoil.

02-04-2019, 07:25 PM	#5
Jamaison Drives: 2016 2SS Garnet Red Convertible Join Date: Feb 2016 Location: North Texas Posts: 138	I just started hearing this on my 2016 2SS -- exact same scenario you described: came home from work, went in the house for 45 min or so, came back to the garage and could hear it coming from front end of car. I thought I was losing my damn mind. It's been doing that off and on for a few weeks now. So has yours ever returned? __________________ 2016 2SS convertible, garnet red, black interior, MRC, NPP, black bowties, low gloss black wheels Ordered 2/4/16, built 3/9/16, delivered 4/20/16

02-25-2019, 07:07 PM	#10
Jamaison Drives: 2016 2SS Garnet Red Convertible Join Date: Feb 2016 Location: North Texas Posts: 138	I managed to catch mine on video around the :20 and 1:14 marks. https://youtu.be/X_4Xgi4P7N8 __________________ 2016 2SS convertible, garnet red, black interior, MRC, NPP, black bowties, low gloss black wheels Ordered 2/4/16, built 3/9/16, delivered 4/20/16

12-22-2017, 10:08 AM	#4
slick3 Drives: Garnet Red - 20 ZLE Join Date: Jun 2016 Location: Southern California Posts: 1,010	Thought I was crazy. I have heard it before a couple of times. Assumed my tinnitus was acting up again LOL

02-08-2019, 08:59 AM	#6
jcor3 Drives: 2018 2SS & 2002 1500HD Join Date: Jan 2018 Location: California Posts: 9	My 2018 SS does it all the time. I thought the neighbors had their golf cart set to reverse in their garage until I figured out it was my car, lol.

02-09-2019, 10:06 AM	#7
sadpanda Drives: 2014 ATS 2.0T 6MT Join Date: Mar 2018 Location: ohio Posts: 66	Try walking out without the key fob... BCM wakes up all kinds stuff when key fob is detected. Trying the door handle without the keyfob should trigger some noises as well. Some 'after run' is normal for cooling fans etc.

02-11-2019, 10:23 AM	#8
protovack Drives: 2019 2LT 2.0T M6 Riverside Blue Join Date: Jan 2018 Location: WA Posts: 847	I think this might have something to do with the HID headlights, I'm not sure though.

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