knocking sound on cold engine

F

Federal

Petrolheads
started bit worried. noticed knocking sound on cold engine. sound gone when engine warmed up. and most noticeable on acceleration around 1800 rpm with more rpm its not noticeable.
put new oil still the same. engine doesnt eat oil. going good. just that sound bit annoying

any ideas what it could be? piston slap? big end bearings?
 
Could be anything, what grade of oil you using??
 
How many miles on engine, you could use a ticker grade oil like a 15/50 if its just from wear and tear
 
Its since i bought car. Then was buy didnt noticed this sound. As guy meet me on his way from work.
 
I'd have said piston slap too. I'd a 98 impreza that suffered from it. Common on late 90's imprezas apparently.... And it was something Subaru addressed soon afterwards.
 
Getting different opinions.
Ones say big end bearings just started other says piston slap third version valves clearance and last opinion timing belt idlers

How to find out wich one right :)
 
[quote author=JOHNNY T link=topic=36898.msg423214#msg423214 date=1360285724]
get it to your mechanic, only way to find out for sure what it is......
[/quote]
will try go tomorrow
 
piston slap happens when your start from cold but goes when its warn

bearing or bottom end would be noisy at a certain rev and gradualy get worse
 
Not to confuse things even more but a dodgy coil can cause piston slap when the fuel is not being burned in the cylinder. Looking at the video there is a definite rock in the engine which is a misfire. It's an easier check a loose connection or a crack at king to the engine. Might be worth a look. :thumbsup:
 
[quote author=Kmboost link=topic=36898.msg423498#msg423498 date=1360616045]
Not to confuse things even more but a dodgy coil can cause piston slap when the fuel is not being burned in the cylinder. Looking at the video there is a definite rock in the engine which is a misfire. It's an easier check a loose connection or a crack at king to the engine. Might be worth a look. :thumbsup:
[/quote]

dont get it :ponder2:
looks like no engine troubles o fault on ecu.
 
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