Loud Squealing Sound on Cold Start, Goes Away after warmup
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  1. #1
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    Loud Squealing Sound on Cold Start, Goes Away after warmup

    In the morning, when I start the car, I get a noticable LOUD squealing sound from the engine bay until it warms up a little. It won't do it if the car has been sitting for a few hours, only in the mornings.

    I did a search, and found some posts mentioning it's the secondary air pump going bad, but no real clear way of diagnosing it. How do I know if that's going bad? What other thing could it be? The car drives fine, but I'm afraid this will begin to escalate as it does it every time now the car has been sitting.

    I'll make a video of it the next time I remember to take my camera out before going somewhere...

    This better not be expensive.... because it sure as hell sounds like it'll be judging by the noise...

    Edit: V6, 78xxx miles, tiptronic; stock air filter.

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  3. #2
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    Loose belt? That's the only thing I've heard squeal loudly in past cars I've owned.

  4. #3
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    If it sounds like a vacuum cleaner its your SAIP (secondary air injection pump). You probably have a vacuum leak to the COMBI valve which will dump hot exhaust back into the SAIP where it condenses and wreaks havoc with the pump.

  5. #4
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    i'd look at your belts. i had an S-10 that did this.

  6. #5
    PZ
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    It could be the serpentine belt tensioner too. I have seen a couple go bad, they are much worse when cold. Easy test is to remove the belt and start it when cold.

  7. #6
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    I had the same problem and it turned out to be a loose belt, accessible when the belly,air control pan is off. A quick fix anyways,

    Hope this helps,

    Chhers,

    Malcolm

  8. #7
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  9. #8
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    Quote Originally Posted by PZ
    It could be the serpentine belt tensioner too. I have seen a couple go bad, they are much worse when cold. Easy test is to remove the belt and start it when cold.
    X2 When my tensioner went at about 105k miles, it started squealing also when first started then tended to quiet down somewhat after a few minutes. After a several hundred miles the sound eventually was more constant, louder and definitely had a metalic ring to it as the ball bearings in the roller started to fail. IIRC, tensioner was about $70 at dealer. If you don't mind a few cut up knuckles not too difficult DIY. Try to pinpoint where the sound is coming from. The tensioner is on the front of the engine slightly right of center. The secondary air pump is on the lower right front of the engine bay and is accessed from below. I also had a secondary air pump go under warranty at about 80k miles. It did have a similar sound but I could easily tell the squealing was coming from the pump.

  10. #9
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    When my car did that, it was the timing belt tensioner roller going bad. I changed it right away to avoid disaster. I'd suggest you determine immediately what the source is, because if it's the timing belt tensioner pulley, you don't want to delay changing it, it will be very expensive if it seizes.

  11. #10
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    I guess I should have described the sound better, I suppose it's more of a whistling noise... Which also, with the hood open, and I rev the engine, it sounds like I have a CAI...

    Which leads me to believe it's the SAIP. But I haven't gotten any CEL's... Problem is, it's only when the car sits long enough to have completely cooled off does it make the noise.

    How do I check the SAIP on the V6? I see tons of info for the 1.8t, but little on the V6.

  12. #11
    I'm Urlik's Hero
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    I had a whistling noise on a '90 Golf which a garage wrongly diagnosed as a fan belt. I had it replaced only to have the alternator (the source of the whistle) die a few weeks later.

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