What is happening? What is this noise?
10-27-2016, 10:54 PM
#21
I PM'd the author of the other thread, hoping that he has email notification of the PM. He has not been on this site since spring, so hopefully he will get the email, and either get back to me ,or chime in here with an answer.
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LT4CMG (10-27-2016)
10-28-2016, 07:01 PM
#22
Le Mans Master
Thread Starter
Thanks a lot, I PMed him too. I noticed he signed in yesterday, really hoping to hear back
10-28-2016, 07:11 PM
#23
Melting Slicks
I say some fluid is loosing pressure. It might be coolant expansion tank, or something to do with direct injection system. I heard up to 44,000 psi?
Fill up the car and retry.
Fill up the car and retry.
10-30-2016, 10:47 AM
#24
Le Mans Master
Thread Starter
Tried to replicate the sound. Friday night was just as cold. Drove the same distance, parked in the garage. Saturday was much warmer and my drive was a bit more "spirited". Came home, checked again, and nothing, not a peep. Odd. Will keep you folks posted
11-18-2016, 10:02 PM
#25
Le Mans Master
Thread Starter
Went out for the final drive of the season, 73 today, but 39 tomorrow, hence the final drive. Out of the blue heard the noise again, about 20 mins after parking. So I'm thinking, maybe the coolent level is low. I slowly unscrewed the reservoir cap, pressure realeased, then it made the noise 3 more times quicky and stopped. I have now pinpointed the noise is coming from the radiator area upfront. I'm sure some may wonder so I'll answer the question now. There is not a drop of fluid anywhere, no smell, and I took the plastic cover under the bumper off just this week; not a drip, no residue, absolutely nothing. I want to now figure out how to check my fluid level. It's either a sticky release valve of some sort or low fluid. Please chime in if you can help.
11-18-2016, 10:24 PM
#26
What is the level in your overflow tank?
11-18-2016, 10:30 PM
#27
Le Mans Master
More than likely they work on lots of Vettes so it's very unlikely they would feel the need for speed.
11-18-2016, 11:24 PM
#28
Le Mans Master
Thread Starter
11-19-2016, 11:52 AM
#30
Racer
Sorry, had to trim the video to be able to upload it here. Drove the car about 7 miles each way to dinner tonight. Came home, went back out into the garage about 15 minutes later and it was making this noise. Please listen, in the video it does it 3 times. It continued making this noise. I started it, shut it off, it made the noise for a couple more minutes then stopped. My car is a 16 z51 m7 with rev match/MRC. On the way home, the fuel light kicked on, low on fuel, but nothing else out of the ordinary. Please help
11-19-2016, 12:05 PM
#31
Le Mans Master
Thread Starter
Runs like a bat out of hell and the steering adjusts instantly between track, sport and tour. No indication of any fuel or steering issues. This does bring up a question though. Is the fuel pump under the hood? I thought it was in the rear
11-19-2016, 10:23 PM
#32
There's a mechanical fuel pump under the intake manifold to build high pressure for the direct injection and an electrical fuel pump in the fuel tank that feeds fuel to the mechanical pump. So no electrical fuel pump under the hood.
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LT4CMG (11-19-2016)
04-18-2017, 10:43 PM
#33
Le Mans Master
Thread Starter
Got my car back today. Long story short, I can now say with 100% certainty that the noise is due to the AC compressor. It is a very rare occurrence on the C7, but it happens and mine was replaced. So sharing this in case someone else is trying to understand why their car is chirping.
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owc6 (04-18-2017),
Rebel Yell (03-18-2019)
04-18-2017, 10:49 PM
#34
Can you give us some more details as to what exactly was found?
04-18-2017, 11:10 PM
#35
Le Mans Master
Thread Starter
The noise is likely caused by a shut-off valve that malfunctions from time to time. Again, an extremely rare occurrence on our cars.
03-18-2019, 11:15 AM
#36
03-18-2019, 11:19 AM
#37
Le Mans Master
Thread Starter
To date, nothing to report. All is normal, no noise or any other issues
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thelastday (03-18-2019)
03-18-2019, 02:08 PM
#38
Pro
Got my car back today. Long story short, I can now say with 100% certainty that the noise is due to the AC compressor. It is a very rare occurrence on the C7, but it happens and mine was replaced. So sharing this in case someone else is trying to understand why their car is chirping.
My Z06 recently started showing this issue intermittently. My fear is that on the day I take it into the dealer the car may not show the chirping/buzzing sound and the dealer will claim they couldn't find anything wrong.
03-18-2019, 02:15 PM
#39
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Interesting read and glad you finally found the source of the noise. It would have driven me 
too trying to find something like that.
too trying to find something like that.
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LT4CMG (03-18-2019)
03-18-2019, 03:22 PM
#40
Le Mans Master
Thread Starter
My dealer was a performance oriented dealer, meaning they did a lot of work on high performance Camaros, vettes and Cadillacs. Take a video, show them this thread, anything to help your cause. Tell them it’s hard to recreate because it’s not an everyday issue.