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16valve horrible clattering noise , whats the cause ?

Discussion in 'Classic Audi Forum' started by MHage, Nov 22, 2005.

  1. MHage
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    MHage New Member

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    My 16valve Coupe with 141,000 on the clock makes a horrible clattering noise , it sounds like a ford diesel ! The car runs fine with 170psi compression in each cylinder . I know this problem is common with 16 valves as my mate had one with 60,000 genuine miles on the clock , full service history etc which sounded worse than mine but went like stink up to the day he sold it years later with the same noise !Before I plan to take the head off please could I have some advice with what the likely problem is and why is this common to 16 valves and not the 20 valvers with twice the mileage etc .The noise does not go away and is present throughout the rev range but more disguised by exhaust noise etc I have been told to lap the valves to the seats but this will only be good for up to 10,000 miles and then need doing again ! why? Could it be the chain linking the cam shafts ?If its the valves why such good compression ?Is it just the hydraulic buckets but if so why not on other engines ?How about the cams , lobe wear maybe ?What is so unique to the 16 valve engine to make such a racket . The car is in superb overall condition but the noise really lets it and me down . Please can you shed some light on this or has somebody rectified the same problem , thank you.
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  2. Rev-head
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    Rev-head Active Member

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    Dont think its the camshaft chain ,it sound like the cog that drives the Distributor very common fault with all of them even twenty valve models,if you take out distributor you will see the wear on the cog ,sure that is the problem

    Tell us how you get on

    Cheers

    ..Steve
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  3. scotty33
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    scotty33 Member

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    Without hearing it, it's hard to say, but I would say that distributor gear noise is not a 'clatter'. A few of my hydraulic tappets are noisy for a few minutes when the car is warming up, at their worst I would call this noise a 'clatter'.
    I've read a few 'fixes' for tappet noise, some say mobil 1 oil works, some say removing the sump and cleaning the pick up pipe strainer works.
    I once changed big ends on an Astra GTE 16v and the tappets were silenced, so it seems improvements to oil flow to the top end help. The astra started tapping again a few months later, so I put 3 new ones in, picked the 3 most worn cam lobes. Ok til I sold it!
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  4. atc
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    atc Member

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    I have owned a couple of 8V Golf GTi's and a 5 cyl 2l Audi one was a real tapper but the noise would eventually go away as the engine heated up. Seized hudraulic tappets are quite common on Audi's and VW's. The 4 and 5 cylinder engines all stem from the same basic design. I have been told that the chain on the 16V linking the cams is almost indistructable so it's unlikely to be that.
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  5. audi5e
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    audi5e Member

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    Tend to agree with the above posts on the tappets. Use a good synthetic oil. If that does not fix the problem then try putting in new hydraulic tappets.
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  6. MHage
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    MHage New Member

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    Thank you , the sound it makes is like the noise of the valves closing at different times ( obviously) a kind of hollow clattering . If the head was off and stripped and you placed a valve in and pushed the valve shut quickly with your fingers then thats the noise it makes , a hollow tap ! but with 16 becomes a clatter , sorry for this but its hard to explain please bare with me !
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  7. atc
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    atc Member

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    Yep sounds like tappets. Over time especially with low usage the oil ways to the hydralic lifters (tappets) become restricted, thus preventing the lifters from lifting. Therefore the cam hits the lifter/tappet from too greater distance and makes a lot of noise.

    The synthetic oil is a good idea! You can also get additives that you put in the oil that are supposed to clean the oil ways for the tappets. I have tried these in the past with no joy. I have since read in Practial Classics magazine that the editor had a similar problem with a Jag and he simply doubled the dose and took the car on a long run giving the car some beans on the way and that did the trick. Try this at your own risk! If you do use an additive I personally would change the oil soon after. Maybe try an additive in your current oil then change to synthetic. But it would be a lot cheaper than relpacing all the tappets!

    Good luck, keep us posted.
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  8. atc
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    atc Member

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    Forgot to say additives available from all good motor factors and often labled as hydralic tappet cleaner. If you are going to try it go for a good quality one, like Wynns or Slick 50.
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  9. gags100
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    gags100 Member

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    do you know when the chains were last changed ? as with mine it wore to such an extent that it had damaged 2 lifters, so had to replace all 16
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  10. scotty33
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    scotty33 Member

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  11. MHage
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    MHage New Member

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    Thank you all for the sound advice , I will post my findings / results when I've had a go at it over the Christmas hols ( if its not too cold !!! ). The way I feel now is that I think I will take out the tappets and replace . I will do the timing belt also as I'm not sure what mileage its done although looks fine .
    Then its onto my power steering problem ( tell you all about it shortly, I know you can't wait ! )but one job at a time and it will soon be up to my sort of standard, cheers ,have a nice Christmas.
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