Sounds like a helicopter
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Joined: Aug 2014
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From: Michigan
Sounds like a helicopter
Posted this in General but I thought I might get a better response here...
Just noticed a helicopter type sound coming from the top of the engine while idling in the driveway. Not like a sewing machine...literally more like a helicopter. Shut it off and started up again - sounded normal. Revved it up a few times - normal. Then it started doing it again. Just passed 100k.
Last night I noticed the oil was low (second hole on dipstick barely covered) so I put a 1/2 quart in. Did I put in too much? Dipstick looks ok...
Not loud enough to hear it in the cabin but I'm concerned. Do I have something going out?
Just noticed a helicopter type sound coming from the top of the engine while idling in the driveway. Not like a sewing machine...literally more like a helicopter. Shut it off and started up again - sounded normal. Revved it up a few times - normal. Then it started doing it again. Just passed 100k.
Last night I noticed the oil was low (second hole on dipstick barely covered) so I put a 1/2 quart in. Did I put in too much? Dipstick looks ok...
Not loud enough to hear it in the cabin but I'm concerned. Do I have something going out?
Last edited by jjaaam; Sep 15, 2016 at 06:58 PM.
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From: Michigan
No recent changes. Only issue is lately coolant has been bubbling out of the surge tank after I shut it off. That has happened twice in the last week. Just put a new cap on it tonight but I have to get some more coolant to top it off. Even though that has been happening it doesn't overheat when driving - only goes over 200 at a long stop.
I dont see how but could the two issues be related?
No codes at all, and it seems to be running fine.
Last edited by jjaaam; Sep 15, 2016 at 09:59 PM.
Le Mans Master
Joined: Sep 2014
Posts: 5,278
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From: Kelowna BC
AFAIK bubbling is likely a sign of a leaking head gasket (causing pressure in the cooling system). Hope others chime in to offer further advice. Unsure why you would get intermittent noise like that... don't know how that ties in.
Melting Slicks
Joined: Jan 2014
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From: Central Florida
air pump check valve and hose blown off somewhere.
Last edited by Forcedvert; Sep 15, 2016 at 10:56 PM.
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From: Michigan
Hopefully not. The bubbling wasn't happening all of the time, and my oil doesn't look foamy...
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Burning Brakes
Joined: Dec 2009
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From: King George VA
If the hose blew off the passenger side check valve (which is behind the intake manifold), you will have to remove the intake manifold to fix it. Unless you have a toddler's hands. The driver side check valve is right at the header on the driver side and obviously much easier to fix.
So you said it doesn't do it on a cold startup, just after the car has warmed up? On a cold start, the AIR pump will run, pushing fresh air into the exhaust manifolds, but turns off after a few minutes and the check valves close.
On the AIR pump itself there is a small vacuum line. I'm ASSUMING this vacuum port helps keep the check valves shut once the pump shuts off, and each check valve is spring-loaded. Someone correct me if I'm wrong on this...? If that vacuum line is broken or has fallen off, wouldn't that allow the check valves to pulse with the cylinder pressure? That could explain the helicopter noise... Just a thought.
I completely removed my AIR system last night, so it's all still fresh in my mind.
Because Race Car.
So you said it doesn't do it on a cold startup, just after the car has warmed up? On a cold start, the AIR pump will run, pushing fresh air into the exhaust manifolds, but turns off after a few minutes and the check valves close.
On the AIR pump itself there is a small vacuum line. I'm ASSUMING this vacuum port helps keep the check valves shut once the pump shuts off, and each check valve is spring-loaded. Someone correct me if I'm wrong on this...? If that vacuum line is broken or has fallen off, wouldn't that allow the check valves to pulse with the cylinder pressure? That could explain the helicopter noise... Just a thought.
I completely removed my AIR system last night, so it's all still fresh in my mind.
Because Race Car.
Last edited by LiteraCola; Sep 16, 2016 at 07:15 AM.
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From: Michigan
Here's exactly what happened:
-Got home after a 75 mile drive
-Left it idling for a little bit so I could turn the wheels to try and look at my sway bar end links (that's a whole different issue)
-Started seeing coolant coming out from under the car. Popped the hood and saw it coming from under the surge tank cap.
-In the process of doing that I noticed it just sounded...different. That's when I noticed the "helicopter" sound.
-Took off the fuel rail covers just to see if there was something goofy going on
-Turned it off. Had my son get in the drivers seat and turn it back on. Sounded like normal.
-Within a few minutes the helicopter sound started again. That's when I made the video.
Here's the big question - will I cause any damage if I continue to drive it? An exhaust leak from the manifold is one thing...but in all honesty I don't know jack-squat about an AIR system so I don't know what the ramifications are of this issue...IF that's the problem.
I don't want to mess it up, obviously.
Burning Brakes
Joined: Dec 2009
Posts: 927
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From: King George VA
Not quite.
Here's exactly what happened:
-Got home after a 75 mile drive
-Left it idling for a little bit so I could turn the wheels to try and look at my sway bar end links (that's a whole different issue)
-Started seeing coolant coming out from under the car. Popped the hood and saw it coming from under the surge tank cap.
-In the process of doing that I noticed it just sounded...different. That's when I noticed the "helicopter" sound.
-Took off the fuel rail covers just to see if there was something goofy going on
-Turned it off. Had my son get in the drivers seat and turn it back on. Sounded like normal.
-Within a few minutes the helicopter sound started again. That's when I made the video.
Here's the big question - will I cause any damage if I continue to drive it? An exhaust leak from the manifold is one thing...but in all honesty I don't know jack-squat about an AIR system so I don't know what the ramifications are of this issue...IF that's the problem.
I don't want to mess it up, obviously.
Here's exactly what happened:
-Got home after a 75 mile drive
-Left it idling for a little bit so I could turn the wheels to try and look at my sway bar end links (that's a whole different issue)
-Started seeing coolant coming out from under the car. Popped the hood and saw it coming from under the surge tank cap.
-In the process of doing that I noticed it just sounded...different. That's when I noticed the "helicopter" sound.
-Took off the fuel rail covers just to see if there was something goofy going on
-Turned it off. Had my son get in the drivers seat and turn it back on. Sounded like normal.
-Within a few minutes the helicopter sound started again. That's when I made the video.
Here's the big question - will I cause any damage if I continue to drive it? An exhaust leak from the manifold is one thing...but in all honesty I don't know jack-squat about an AIR system so I don't know what the ramifications are of this issue...IF that's the problem.
I don't want to mess it up, obviously.
All the AIR injection system does is inject fresh air from the intake into the exhaust manifolds to quickly heat up your catalytic converters and reduce cold start emissions. To be honest, if it wasn't working properly, you would get a CEL.
I can't honestly say nothing will happen since I dont know 100% what's going on with your car.
Did you by chance overfill the overflow reservoir? There is a "Full-Hot" line right at the seem of the tank.
Last edited by LiteraCola; Sep 16, 2016 at 08:29 AM.
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From: Michigan
All the AIR injection system does is inject fresh air from the intake into the exhaust manifolds to quickly heat up your catalytic converters and reduce cold start emissions. To be honest, if it wasn't working properly, you would get a CEL.
I can't honestly say nothing will happen since I dont know 100% what's going on with your car.
Did you by chance overfill the overflow reservoir? There is a "Full-Hot" line right at the seem of the tank.
I can't honestly say nothing will happen since I dont know 100% what's going on with your car.
Did you by chance overfill the overflow reservoir? There is a "Full-Hot" line right at the seem of the tank.
The overflow issue is new. Last Friday I cracked 100K miles. Great! Got home and put it in the garage and saw coolant coming out. Went on vacation and did some research...ordered a new surge tank cap.
Filled it up when cold to the line on the tank when I got home from vacation and drove it a few more times with no overflow. Then it overflowed again yesterday as I described. New cap came yesterday so I haven't had the chance to try it out yet.
Last edited by jjaaam; Sep 16, 2016 at 09:02 AM.
Burning Brakes
Joined: Dec 2009
Posts: 927
Likes: 6
From: King George VA
Thanks for the info. Always appreciate the help!
The overflow issue is new. Last Friday I cracked 100K miles. Great! Got home and put it in the garage and saw coolant coming out. Went on vacation and did some research...ordered a new surge tank cap.
Filled it up when cold to the line on the tank when I got home from vacation and drove it a few more times with no overflow. Then it overflowed again yesterday as I described. New cap came yesterday so I haven't had the chance to try it out yet.
The overflow issue is new. Last Friday I cracked 100K miles. Great! Got home and put it in the garage and saw coolant coming out. Went on vacation and did some research...ordered a new surge tank cap.
Filled it up when cold to the line on the tank when I got home from vacation and drove it a few more times with no overflow. Then it overflowed again yesterday as I described. New cap came yesterday so I haven't had the chance to try it out yet.
In that case, the seal on the cap is probably worn out. If it's filled to the mark it shouldn't overflow at all. Something tells me that's not related to the helicopter noise.
Have you checked all the hoses on the AIR check valves? The one behind the intake manifold will be difficult to see, but you should be able to find it with a flashlight.
Last edited by LiteraCola; Sep 16, 2016 at 09:22 AM.
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From: Michigan
In that case, the seal on the cap is probably worn out. If it's filled to the mark it shouldn't overflow at all. Something tells me that's not related to the helicopter noise.
Have you checked all the hoses on the AIR check valves? The one behind the intake manifold will be difficult to see, but you should be able to find it with a flashlight.
Have you checked all the hoses on the AIR check valves? The one behind the intake manifold will be difficult to see, but you should be able to find it with a flashlight.
Thanks!!
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From: Michigan
So I just now noticed this. Drivers side. I'm assuming it's some sort of vacuum line. Stupid mice must have chewed it through.
What is this little hose for, and do you think that's the root cause of the problem?
Last edited by jjaaam; Sep 16, 2016 at 05:51 PM.
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Started it up and put my thumb over the broken end that is towards the front of the car. Felt vacuum pulsating. And the minute I did that the helicopter sound stopped.
This line has a small green plastic **** on it that says "hand tighten only". Is this one of the AIR check valves? It looks like an entire hose assembly going from the front to the rear of the engine.
I can't seem to find a picture of it online so I can order another one.
Any ideas what it's called? Safe to drive?
This line has a small green plastic **** on it that says "hand tighten only". Is this one of the AIR check valves? It looks like an entire hose assembly going from the front to the rear of the engine.
I can't seem to find a picture of it online so I can order another one.
Any ideas what it's called? Safe to drive?
Last edited by jjaaam; Sep 16, 2016 at 06:44 PM.
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From: Michigan
Got the answer here:
https://www.corvetteforum.com/forums...post1593074023
Thanks to neutron82 for the help!
https://www.corvetteforum.com/forums...post1593074023
Thanks to neutron82 for the help!
Last edited by jjaaam; Sep 16, 2016 at 10:00 PM.