Piston Slap

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Mon 26 May 2003 13:19
Piston Slap - kam
I own a '99 VW Golf 1.4 which has always had a pronounced ticking from the engine, initial thoughts are possible camshaft wear although the car has only done 53k but further investigation has led me to believe that it is piston slap. After contacting VW UK they do not want to know as the car is now over 3 years old!
Could you tell me if this is a known problem and is there anything I can do about it?
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Mon 26 May 2003 13:53
Piston Slap - Dynamic Dave
More likely to be the hydraulic valve lifters (or tappets, if you prefer) which is a common problem with Golfs; or at least it was with earlier engines anyway. Is the ticking louder/more clattery when the engine is initially started up?
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Mon 26 May 2003 16:04
Piston Slap - Aprilia
Typically piston slap is heard as the thrust side of the piston 'slaps' the cylinder wall - usually only when the engine is cold and the piston is the 'wrong' size. As the piston heats up it expands and so the slap ceases (or is much less pronounced).

Hydraulic tappets on the other hand (on Golfs) tend to clatter a bit for the first few seconds and then very soon quieten off.
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Mon 26 May 2003 19:07
Piston Slap - Matt A W
I really don't mean to be a doom monger but my Golf 1.4 needed a new engine after 8000 miles! It had always sounded pretty rough but it started sounding more and more like a diesel, especially when cold. It was most noticeable under load first thing in the morning when it had a pronounced 'knock'.

When I took the car to my dealer, I had barely finished describing the problem when the foreman said that it will need a new engine. As you can imagine I was horrified. Apparently there is/was an issue with certain 1.4 16v engine losing a teflon coating on the pistons which causes the pistons to 'slap' resulting in the noise I was hearing - at least this is what I was told. VW was aware of the problem and was replacing engines as soon as somebody reported the issue rather than recalling cars which would be hugely embarrassing for them.

Apparently my 2000 model car was one of the last to be affected by the bad batch of pistons so your 1999 car could well be suffering the same problem.
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Mon 26 May 2003 22:03
Piston Slap - John S
kam

Matt A W is right. Piston slap is more a hollow-sounding knocking or clonking from the area of the block than a tapping noise. As he says, it usually fades as the engine warms up and the pistons expand - the expansion of aluminium being greater than that of iron.

Tapping is usually associated with the top end of the engine. However, if it does emanate from lower down, suspect piston damage.

Regards

John S
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