Iv had my impreza for a couple of weeks now, it makes a knocking sound when cold, and literally lasts for the first 5 - 10 mins then it is completely gone once the car is upto operating temp. i filmed it this morning so i could put it on here.

From what iv researched it sounds like piston slap or cambelt tensioner or both.
The car has 84,000 miles on it with good history, however it is due a cambelt change. There are no issues when upto normal temp, drives fine, no noises and the sound it had when cold has completly gone.

What do you think it could be....

Cheers in advance.

2 vids here

http://s606.photobucket.com/albums/t...0cold%20start/

 

has the engine been forged? because forged engines are i little noisier when cold

 

It's a similar sound to my old Legacy which had Piston slap, only alot louder.

 

as far as im aware it hasnt had forged pistons etc, Tim are you saying the legacy was louder or my car is? cheers

 

Sorry, yours seems louder. Mine went away when warm as well, which they say is the thing to look for. I'd say its nothing huge to worry about, but it may be worth getting a specialist (you can trust) to take a look at it.

 

Had this exact problem on my old sport and eventually it got a bit louder for longer in the mornings ..and got a bit to annoying for me so I broke the car in the end ...but if u can deal with it I wouldn't worry

 

has anyone had experience with the cambelt tensioner? i found vid on youtube that i thought may have a similar noise to what ive got possibly? or is it more likely piston slap? Is there anything that can help with piston slap if thats what it is ?

http://www.youtube.com/watch?v=2J0vgN_nJbs

cheers

 

i dont think its a tensioner because it stops when the temp is normal

 

It does seem like piston slap but it is much louder than mine. Just make sure you warm it up properly (i.e. 5 miles of driving) before you boot it and it'll probably be ok.

Mark

 

any other thoughts please?

 

Ive just took my 60K 98 WRX block out and replaced it because of piston slap. The symptoms i had are identical to what you have.I had the tensioner checked as i read various posts on different sites saying the noise could be this and also had it checked out my a Subaru mechanic,it wasnt that. Besides the slap from cold it was fine and pulled very well but i couldnt put up with the noise when it started as i have OCD!

Just watched your vids, if you flick the revs in the engine bay when warm do you hear it just slightly as you flick the revs up off tickover?

P.S Whereabouts in west mids are you mate, could pop round weekend and have a listen?

 

cant hear it at all when warm, which i guess is a good sign, even from underneath.

iv just changed the oil last nite, so il see if its any better with this slightly thicker stuff (quieter).

i flushed the engine and had some clumps of fibrous material come out, kind of like cotton strands all mixed together, imagine hair on bath plug but smaller scale, so maybe that could have been restricting the oil movement when cold? il post up my progress.

Im near cannock mate, you?

 

If your only in cannock pop over to Pole Position in Wolves mate, Have a chat with them and they'll take a look for you. Top Guys!

 

i didnt even no they existed mate, thank you! do they remap? do u have number?

 

Phone Number is 01902 605037

And address is Pole Position UK Ltd.
South Street
Willenhall
West Midlands
WV13 3TG

They do everything mate, Matty from there is on here but is currently on holiday. Recently finished a 400+ conversion on one of my wrx's.

Get yourself signed up on the west mids section too if you havent already mate

 

Definately piston slap mate, mine does it when cold, sounds like a bloody diesel for about 5 - 10 mins. It's fine once warm though. no smoke or anything, Makes sense cause the piston rings expand when the engine warms up making a tighter seal, so the noise goes away.
I find it really irritating but I can wait til I can afford to sort it out, I wouldn't worry too much i've heard stories of people having piston slap for 30,000 miles and not had any issues.

 

Mine has slapped for the last 60,000 miles.

 

I have Forged pistons in my wagon and it is noisey when cold but not a loud as that. Strange what you found in the oil have you a catch can? is it using any oil?

 

Could be material from your oil filter - if you've still got it dissect it and see what's inside, if a foreign body has ripped the filter fabric that might explain the fibers.

 

BTW did the chap you bought it off allow you to start it from cold when you viewed it or did he tell you upfront?

 

Right a bit of an update chaps. I started her up this morning, and it was a lot quieter!! and after about 2 mins driving it was very quiet!

now i put a 15w oil in so this could be helping, but i definatly think its due to the fibrey stuff i pulled out ~(See pics)

I am thinking this may have been causing a little oil starvation when cold, as it would probly be sitting hard in the block, what do u think?

the chap i bought it off didnt tell me anything about it apart from letting it warm up is a good idea, the engine was warm when i got it, so i guess i know what to look for next time!!

There's a video of this mornings start up called new start up. (most of the noise is exhaust because i'm by a wall) and a couple of pics of that s**t that came out after a flush.

All here, see what you think, watch the old cold start compared to today.

http://s606.photobucket.com/albums/t...0cold%20start/

*and no its not using any oil, no leaks etc all clean underneath, iv got a gauze filter in my funnel that i use to put oil in, but i always filter the old oil into the drum using it, so thats how i can see what is in the oil if anything.

 

Just listened to the vid mate, thats alot better isnt it,you can barely here the slap. What oil have you put in,what year is she btw?
Yeah id say he knew it was slapping a bit but i think he thought it was more serious than it actually is. Did you get it for a good price?

 

its a 99 V reg mate, i put some 15w 40 castrol gtx in it as a temporary oil, i just wanted to see if the thicker stuff would make a difference before i shelled out for some better stuff (will probably flush it again when i do it)

Yeah i got it for a good deal, if we meet up one of the days il tell ya :-p
but i think you are right about the guy i got it off. He probly thought it was shot, but then it was overdue a service by 4k miles when i got it :-/

 

Good stuff Man

 

i have no idea wtf piston slap is,my engine sounds like that when its cold, i thought they all did? sounds like a normal engine in every scoob to me with high mileage which most have! i wouldnt worry if its gunna go bang its gunna go bang lol

 

my legacy gtb had it gone when warm nothing to worry about just not a nice noise i sold mine now but ive heard of gtb's with 30000k on with it devoloping so let it warm up should be ok

 

Update for all of those guys googling piston slap etc, this ended up NOT being piston slap, it was in fact one of the tensioners on the cambelt. Had new belt, tensioner and pulleys fitted and runs sweet as a nut now. Hope this helps someone. was a bit late updating but hey ho.