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mr.oogieboogie

strange noise piston slap?

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well I had noticed a strange noise coming from the car (on tick over and low reves) sounded a lot like exhaust leak. I knew there was a stud missing so i took the manifold off and replaced 3 studs and refitted the exhaust. noist still there. when fired up it sprayed what looked oil out of the exhaust but it may have been petrol.. car drived fine and has plenty of pull. so im wondering if its not fireing on one cylinder (as it seems similar to when one of the coils went the other year and it looks like one of the coil packs has a split) I will pull the plugs one at a time to see if the noise goes tomorrow evening.

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 any advice welcome

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I don't think that is piston slap. I'm betting my money on a gasket in the exhaust somewhere. I have also heard a loose spark plug sound like that, but your noise seems to be focused on the bottom side of the engine.

Use the old plastic tube in the ear to listen, you'll find it.

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That's a hole in the manifold somewhere, mine sounds similar, good luck

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I'll throw in lifter, (noisy tappet) check oil level and condition.

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oil should be in top condition as car has only done a couple of hundered miles since last oil and filter change oil level is fine and clear. cant see a leak or hole anywhere on the exhaust manifold or further down the exhaust, no cracks or pinholes. maybe gaskets as i noticed that a couple of them has seperated as they were tri ply but i was unsure if they were seperates that were built up like shims. the turbo gasket looks like new (well it was new a couple of hundered miles ago)

noise is from the bottom of the engine. goes away when accelerating but returns when at low reves and tickover. Car does not get hot and drives well. but im concerned about the black spray thet came out of the exhaust could have been moisture and crap.

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"goes away when accelerating but returns when at low reves and tickover." points to low oil pressure, (lifter).

Million Dollar question, are you using the same oil as previous, or have you changed brand?

Do you see any abnormalities in the readings of the pressure gauge, hot to cold ?

I had a Mazda 626, every 9000 kl a lifter would start to rattle on start up, an oil change fixed it, so my 10,000 kl service schedule got shortened to 9000, no issues.

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Lets hope it isnt end float or big end bearing.

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I lost an engine through end float, was about 8mm, it sound sweet as a nut before I pulled it apart.

So may not be that, personally I would not run it too much until u understand what's going on.

Good luck

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When you drain the oil check for bits in it, it would be worth eliminating end float, does the clutch feel right, sometimes end float can be felt, gently lever the crank pulley to see if there is any movement.

Not sure but it might be worth, and some should confirm this, when on tick over remove each spark plug lead in turn to see if it makes any change to the sound.

Hope this helps.

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Best of luck with it Peter.

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Well i took the plugs out and a couple ofvthem were very oily. Cleaned and put back in. Noise is still there but not as bad. If i take the 2nd plug lead from the fire wall off the noise stops. So im thinking lifter

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That would be my thought as well.

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What mileage has the car done. If two plugs are oily then manifold gasket will not affect this although it could be the source of the noise.

 

Have you done a compression test to check the state of the engine. If all ok then oily plugs and oil spraying from exhaust will indicate other problems such as turbo oil seal.

 

Its beginning to look like you might need to delve a bit further and check the liners etc  

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Well big thanks to derek aka sailorbob for having a spare set of gaskets and dropping them off. Finished fitting them in the early hours this morning. Now the car sounds as it should. Big relief.

Had a good look at dereks new manigold. Nice piece of kit

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