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I really don't know how else to describe it. Car has no issues starting or running, but for about the last 2 months every time I cold start it, the engine makes a sharp, high-pitched noise like a sneeze.

Can anyone tell me what this is or why it's happening?

UPDATE:

Ok, I finally managed to record the noise. I realised in my attempts to record that it certainly does not happen "every time". It happens maybe one time in ten, and rarely on a cold start. More often than not, it happens after I've been driving for a while and then stop and start the engine.

Here's the link to the video. You can clearly hear the squawk just after it starts.

http://www.youtube.com/watch?v=UlqBFf63wXE

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  • Do you think you could record the noise? Sneeze and high-pitched are kind of ambiguous ways to describe engine noises...
    – vlsd
    Nov 3, 2013 at 22:15
  • yes, I'll record it today and edit my original post
    – roryok
    Nov 4, 2013 at 6:51
  • A "sneeze" usually means air is coming out of something it shouldn't. That means a crack in an air hose or a clamp that's not tight enough, or your turbo's plenum(or is it called a diaphragm?) may have a tear in it. But this is the first time I've heard about it happening on start-up. Best thing is to open the engine bay and record a video while someone else starts up the car. Also try to focus in on exactly where the noise is coming from as that will help isolate the cause. Nov 4, 2013 at 11:54
  • I tried recording the sound this morning but it didn't make it. I should explain this issue is intermittent. Frequent, but not constant.
    – roryok
    Nov 4, 2013 at 15:38

2 Answers 2

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We have a Mk4 TDI Jetta that makes a sound after startup that might be described as a sneeze. I'm fairly confident that it's the starter motor's overrun clutch.

As soon as the engine "starts," it begins turning faster than the starter can turn. For this reason, starters have a one-way clutch, called an overrun or sprag clutch. This permits the starter to turn the engine, but prevents the engine from turning the starter, protecting the starter.

On my vehicle, I imagine there's some play or a worn bearing in this clutch, because as soon as the engine fires, there's a short (~1-2sec) buzzing noise that starts high in pitch and decreases in pitch quickly as the sound dies away. One might desribe this sound as "throat clearing" or "sneezing" in nature.

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  • I'm still trying to record it, as it tends to not happen when I have the camera on it (bloody typical). Mine lasts less than 1 second, and doesn't change pitch. It's probably better described as a kind of squawk like a chicken might make. I'll try and record it again this evening.
    – roryok
    Nov 4, 2013 at 15:40
  • 2
    problem solved. turn on camera before starting car.
    – mac
    Nov 4, 2013 at 17:25
  • =) thanks mac, that seems to be working alright
    – roryok
    Nov 5, 2013 at 6:59
  • Have you checked the tension on your belts? A "squawk" could also be a belt slipping ;) Nov 6, 2013 at 9:13
  • @roryok I just watched your video. That's the same sound that I was describing. For what it's worth, ours has done this off-and-on for years now. It may grenade itself to pieces at some point, but so far so good.
    – mac
    Nov 8, 2013 at 15:14
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This is a noise typical to Volkswagens. It is the starter motor. The starter motor extends into the bell housing of the gearbox. The extension on the starter acts as a support for the front of the starter motor. It runs in a bushing which becomes dry over time. You can either ignore it, or remove the starter motor and with a long artists brush and put copper based grease into the bush, then refit the starter. The noise is the starter slowing down and chattering in the bush.

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  • Been there and done that. Never thought of the chatter as a sneeze, but in retrospect, it does sound similar.
    – mongo
    Sep 18, 2019 at 13:22

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