TARManiAC

occurs only when engine is cold i.e. first start of the day.
When engine is warm there is no noise. Suggestions had it that
it was a belt tensioner, but others said that this one also
was noisy when warm. Does piston slap noise go away when
engine is warm? My dealer came to me one morning to listen
and he said that many Impreza´s had this noise when cold until
pistons had warmed up and expanded and that it definately was
not a belt tensioner as it was a much louder noise. The noise
is hearable both inside and outside the car. Occured first
time at 3500 km´s. Car has now 4300 km´s and noise has not
gotten worse. Normal? They all do that sir? others had this?
HELP

chrisp

Yep its disappears with the engine warms up. The biggest problems were on the last of the phase one engine MY97-MY98. Very rare on an engine after that but I have read about a few. The cure for the MY97/98 was either a new short engine or a replacement piston. The noise is caused by the piston rattling in the bore and only has a be a few '000s out. As your dealer says as the engine warms the piston expands so there is no play and no slap.

Do a search on here for piston slap there is .wavs file and loads of stuff.

good luck

ChrisP

[Edited by chrisp - 11/25/2002 10:14:57 PM]

TARManiAC

appreciate the help. Should I wait and see if it gets
worse, and if it doesen´t then just live with it?

chrisp

I would try and get it fixed under warranty (thats what they are for ), if it is piston slap its a well known fault on imprezas but the problem is not that common on MY01 engines. Looking at your location you arent dealing with Subaru UK so I wouldnt know if they would look at it in the same light.

scoobyslut

would suggest geting it fixed under warranty,afterall, Subaru Uk do know of problem and have parts on the shelf to fix it, as simply replace the one noisey piston now. At least then, when it comes to resale, you aint gotta explain about the noise or why you are only selling it with the engine "warm"!

HELLOM8

Get on to the dealer and say the noise is unbearable and removing your enjoyment of the car etc. Funny noises should be fixed under warranty, don't just put up with it.
Cheers.
Ian.

TonyBurns

iTrader: (3)

TARManiAC,
Try changing the oil in your car, it sounds silly but depending on which oil the dealer uses it could just be the tappets (which will sound loud until the car is warm if the oil is thin).
Its very rare that a phase 2 engine suffers this problem but it isnt impossible, oil is your cheapest option to start with (go for a 15w50 rated,Mobil1 motorsport or Motul 300v or 10w60 Castrol RS fully synthetic).
If the symptoms stil persist then pursue the option that its then piston slap, it would be ashame if it was only down to a thin oil and noisy tappets though.

Tony

TARManiAC

Thanks guys for all the help.

TonyBurns I don´t know if the oil is especially thin.
It is Duckhams 10w40 and is what my rallydriving dealer
uses in his rallycar and for 8 hour endurance crosskarting
with Subaruengine. Wouldn´t using a thicker oil to cure
the noise just be disguising the problem? or is this
common pratice?

Claus

TARManiAC

Ok now i´ve read all the posts bout piston slap. From
listening to the sound files mine doesen´t sound like this.
But then again it could be difficult to determine a noise
via a computer. I would say that slap is more like a rattle
whereas mine is more like a knocking. I forgot to tell that
the noise does not get louder by increased rpm´s more like
the opposite, it becomes more difficult to hear.

scoobyboy

check the paint mark on the tensioner if it's blue get it changed for the modded type with a green paint mark.

TARManiAC

But I only get the noise when engine is cold so I tought that ruled out the tensioner. Like I posted earlier, my dealer listened to the noise and said it wasn´t the tensioner as it would make a completely different noise according to him.

DO'B

Excuse me, don't all the late cars have shimmed tappets?? in which case it can't be tappet noise.

TARManiAC

My car now has 11000 km´s (6875 miles) on it and the noise is still there. Nor worse nor better. And still only when engine is cold. My question is: If this noise is piston slap would it normally had gotten worse/louder in 7500 km´s (4687 miles)?
I ask because servicetime is up soon and if necessary I will tell my dealer to fix it. On the other hand I´m not interested in having
some careless mechanic (i´ve had some bad experiences with Volvo) taking my engine to pieces if it is not a must. Can the slap develop to an enginefailure or will the noise always be the same? I listened to the sound file and I doubt that the engine was like this from new??

Oh, by the way Belgium is white at the moment and I´m having alot of fun. How is it over there?

naturbo2000

piston slap can be heard best through a (very long) screwdriver. With the engine running, put the end of the screwdriver on the cylinder and the handle to your ear - a healthy cylinder just makes swirling noises, a bad one makes slight knocking sounds (even when the engine has warmed a little). You can see why it needs to be a long screwdriver (about 60cm)!

Generally clatter at startup is normal, but sounds very similar to slap.

How do I know? - mine was diagnosed a fortnight ago - very minor but there...

scoobyboy

the tensioner noise can be mistaken for piston slap and can be there when hot cold or both i.m will ask the dealer to change this as they say piston slap does not appear on that year engine.

naturbo2000

I promised someone I'd post a little more on the subject. I can't promise the accuracy of anything written here and would appreciate it if someone can tell me I'm talking ut of my @ss.



MY 97 and 98 are most likely candidates for slap, since Subaru changed the engine design, and put too short piston heads in... Hence the fix for such engines is pistons with a slightly longer skirt (so they rattle less).

The difficult thing is that (apparently) most scoobs have engine clatter of some description when they're cold - and asking about mine (and having it checked 6 months ago) met with the response "no diagnosable fault" and "they all do that". I haven't had a scoob before the current one, so have no point of reference.

All I can offer is that you have it checked by a Subaru Dealer - preferably from cold (i.e. leave it overnight). Chance of long term damage is apparently slim - any fix need only be applied if it worsens (cost of fix is driven by labour costs to take the engine appart - 57 quid an hour at most dealers!).



Hope this helps.

TARManiAC

Now that my tensioner has been changed the noise is still there.
What will happen next is that some "expert" from the importer will have a listen at it and tell me "they all do that, can´t help you".
I WILL NOT take this as a new engine should not make a knocking noise for the first 10 min. it is started. What about cylinder ovality as the miles and years pile on? I intend to keep my car for many years for tax reasons (Denmark).

Claus