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The dreaded piston slap - I need answers (please)

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Old 11 October 2000, 12:52 AM
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scoobysnacks
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I know this is probably a drivetrain post, but no-one has replied to me there, so:

I've got an MY98 WRX (42,000 miles )and it appears to be suffering from piston slap (knocking when cold, goes away when when hot). Now, can anyone tell me the definitive answer to this question? - How serious is piston slap? Will my engine explode, implode, melt, die etc. or will it just continue with no other simptoms other than the cold knocking noise. It's been doing it for at least 5000 miles, but probably longer without me really noticing until I read about it - I've only had the car since early this year, 9000 miles ago). It's not burning any oil and I haven't needed to top up once, before or after my recent service. How worried should I be? How much to fix it? Is it worth it? etc. etc.
I've been told by a porsche mechanic that I shouldn't really worry, just maybe take a more serious look at it in a few years (90,000 miles or so). Is he right or should I really sort it out straight away before something nasty happens? If so, can anyone recommend a contact name/number of someone who may be able to help, preferably not too far from the Bedford(ish) area.
Thanks for any help.
Old 11 October 2000, 03:19 PM
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scoobysnacks
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You got my hopes up then as well when I saw there had been a reply....
Does anyone have answers for me???
Old 11 October 2000, 05:50 PM
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AlexM
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Scoobysnacks,

Sorry for the off-topic post. This thread had a reply count of minus 3.

WRT to your post - I would go along with your mechanic here. I think everybody gets in a panic about piston slap, but provided it is quiet when warmed up you shouldn't worry too much. It obviously isn't ideal, but doesn't imply immediate doom . I've had two turbo cars which have had piston slap to some extent with no more serious problems resulting.

If you can get it done as a warranty fix then go for it, otherwise wait until it needs seeing to and carry out a major overhaul at the same time. You should get plenty of warning if the piston clearences are too big when running at normal temps.

Cheers,

Alex
Old 11 October 2000, 06:48 PM
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Shark
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Sorry to hear about your problem.

My thoughts are that it won't get any better, and that you should get it sorted (ie new piston and rings) before it damages the block.

Keep a very close eye on oil consumption as a sign that things are getting worse.

Thats my opinion, perhaps some real experts will reply. I'm not sure how long before block damage will occour.

David

[This message has been edited by Shark (edited 11 October 2000).]
Old 12 October 2000, 09:02 AM
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scoobysnacks
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Thanks,

As it's a third party warranty I've got, I'm sure they'd refuse to replace pistons etc. especially considering that some dealers even argue the case. I guess the costs would be very high if I paid for such work, so I couldn't really justify that unless some other symptoms appeared. I'll certainly watch the oil level. I'm considering taking it to a Subaru specialist for a check out anyway to get another opinion. Maybe Lockyear Cars. Anyone got any experience of them or other recommendations?
Old 12 October 2000, 09:11 AM
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Steve Wilson
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Don't worry unless the noise is audible when the engine is warm. Many engines are noisy at startup so you are probably worrying over nothing.

If it starts to tap when the engine is warm get it fixed soon.

When and if your engine does make the dreaded 'slapping' noise when warm it is more likely to be a bigend bearing problem than a piston wear problem.
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