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Whistling at idle = Vacuum leak?


briandye

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Noticed when I got my Edge back on the road (09 Limited) in the carwash baby with it running, I heard a slight whistle noise. Didn't think much of it, but then noticed it again recently and it's bugging me.

 

After searching online, it seems to be a vacuum leak, which makes sense. I have no experience with the vacuum system on a vehicle, nor how to check it. I saw some videos and they said to have the engine running, and spray some kind of parts cleaner, or starting fluid around all the vacuum lines to narrow it down (the RPMs should surge a bit where the leak is).

 

I was just wondering if there are any common spots on the Edge where hoses or connectors might wear out to cause a leak? The only symptoms I have are in the mornings, my idle will drop a little lower than normal for a split second, then go right back to normal. Not a fast "surge" just a small dip and then back up.

 

It ONLY does it at idle, if I touch the gas pedal at all enough to raise the RPMs then it will stop.

 

I'll try that spray trick later on today and see if I can't track it down.

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I have the same issue! I just didn't think much of it to post and it's never gotten worse. Now I am reading that vacuum leaks can affect acceleration and shifting, an issue I have been having since the purchase of my car just hasn't been bad enough for me to say something

Edited by mcali6301
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  • 2 weeks later...

Check Engine light came on yesterday evening and I brought it straight to the dealership.

 

Prior to this I was testing the brake booster by following some instructions online. The instructions were to, with the engine running, depress the brake, the sound of air should be heard but then go away, the rpm should raise slightly and go back down...Instead the sound of air continued and the rpm stayed slightly raised.

 

From my perspective, it seems as there is a vacuum issue since there is also a slight acceleration and hesitant shifting issue. It all has been extremely minor to me, I thought perhaps the car just had a lower quality tranny but all I needed was for that check engine light to come on to really confirm some kind of issue and better plead my case to the dealer.

 

Luckily I have the extended warranty...Will keep you guys updated.

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Check engine light was due to the following:

 

P0456 Ford Description

This diagnosis detects leaks in the Evaporative Emission System (EVAP) purge line using engine intake manifold vacuum. If pressure does not increase, the Engine Control Module (ECM) will check for leaks in the line between the fuel tank and EVAP canister purge volume control solenoid valve under the following vacuum test condition.

The vacuum cut valve bypass valve is opened to clear the line between the fuel tank and the EVAP canister purge volume control solenoid valve. The EVAP canister vent control valve will then be closed to shut the EVAP purge line off. The EVAP canister purge volume control solenoid valve is opened to depressurize the EVAP purge line using intake manifold vacuum. After this depressurization is implemented, the EVAP canister purge volume control solenoid valve will be closed.


Read more: http://engine-codes.com/p0456_ford.html#ixzz3WB0DzwR0

 

Remaining issues are being looked it but it seems to me that everything is pointing the "vacuum" lines or system.

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Another update: Brake booster internal failure and its' being replaced. I know this is not directly link original thread but once they do replace, they will then address the whistling issue if the brake booster wasn't the cause to begin. I'm pretty sure there is a vacuum line that runs into the brake booster.

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Mechanics found nothing else wrong with car aside from the brake booster. They test drove it with a scanner and they found no issue. I'm very curious now to see if the whistling has gone away, I doubt they'd even be able to hear it where they are but once I get in my driveway I'll know.

 

I'm not too convinced it was the brake booster causing the whistling since when I tap the gas, it gets a little louder and goes away..

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Whistling still exists however I noticed better acceleration. Perhaps since the brake booster was connected to a vacuum line, replacing the brake booster formed the necessary seal within which let the vacuum line operate normally for the throttle body? Can only guess...

 

Obviously the mechanic could not hear the whistling and since there are no issues with the car that they can fin, I don't think there's any reason to push it.

 

The only other thing I can think of is the throttle body, they mentioned getting it cleaned but I've heard so many conflicting opinions on this. (I've seen the very long threads on the TB)

 

Perhaps I'll get it done during next maintenance.

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  • 3 weeks later...

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