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weird tapping noise? Help!

Discussion in 'A4/S4 forum(B5 Chassis)' started by B5QUAT, Mar 4, 2013.

  1. B5QUAT
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    B5QUAT Member

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    Noticed the other day with my window down while the car was static quite a loud tapping coming from under the bonnet.

    It sounds to be coming from where the injectors are and it is worse when the engine is warm. It's a metallic tap about once every quarter second.

    Any ideas??? Noisy injector? valves?

    Any help appreciated
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  2. Bradderz_1988
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    Bradderz_1988 Dont replace it, Upgrade it !!

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    Could be the cam chain tensioner due to low oil or lack of pressure also could just be the purge canistor solenoid valve on top of the airbox.
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  3. B5QUAT
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    B5QUAT Member

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    Cheers mate I'll check that out.
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  4. B5QUAT
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    B5QUAT Member

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    You were right. Oil was low. Topped it up and it's quiet as a mouse. Thanks. Thought these things has a low oil light? Mine never came on???
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  5. Danny-boy
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    Danny-boy Member

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    Odd.

    I had exactly the same on my B7 2.0T yesterday.

    Sounded like the cooling fan blade was hitting something, very worrying.

    350ml of Castrol Edge and all is perfect.

    I'll be monitoring more carefully from now on!!!!
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  6. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    How low? I've run mine off the dipstick before and its not made any noises.
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  7. Danny-boy
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    Danny-boy Member

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    So have I.

    I've had it off the stick before and it's not made noise, this time it was just below min and sounded terrible.
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  8. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    Incidentally, on my old A4 which had a knackered oil pump, a combination of hot oil, lots of idling and a low oil level would make it start tapping really loudly.

    Driving around town in stop start traffic used to be really bad if the engine was fully warmed up, and i ended up holding the revs up around 1500rpm while stationary which built enough pressure to quieten it down.

    It was mainly due to a worn out oil pump though, i guess the low oil level just meant the pump had to work harder and it couldnt keep up.

    It stayed like that for about 30-40 thousand miles, although towards the end of that time, any length of idling, even with a full sump, would start it tapping unless you held the revs up. I stuck an oil pressure guage on it and used to register only 8psi of oil pressure at idle!
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  9. B5QUAT
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    B5QUAT Member

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    I put a litre in and it was halfway up the stick so quite low!
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