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Old 11-09-2003, 05:15 PM   #1
slowme
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Question Engine Knock

This is on an MY00 RS.
When the engine is cold I can hear a knock coming from the engine. It is faint at idle, but around 1,500-2,000k on the tach it's pretty loud. After the car warms up the sound is still there, but not as loud as when the car is cold. I took it to the dealer and they said it was the timing belt tensioner. They said they replaced the tensioner...but the bolts look like they weren't touched. The sound was still there, so I brought it back to the dealer. This time they said that piston slap was the cause, that it was normal and to not worry about it. They even gave me a copy of a service note http://www.endwrench.com/current/win...03/insider.pdf Page 4 "Engine noises when cold"

I can't believe that this is normal for a car with 50k.

Anyone have any input?
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Old 11-09-2003, 05:23 PM   #2
NicEJ25
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if you have piston slap at cold. it's about normal. if it still slap when hot, then it's no more normal, nor acceptable. the dealers have been told to replace the short block under warranty when engine emit piston slap noise at normal operation temperature. if you're still under warranty, go and shout at'em loud. if not, well, wait until something fail to open the engine or change the shortblock. you could wait long. 200K miles long...
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Old 11-10-2003, 12:18 PM   #3
marcus12
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Noisy hydraulic lifters? Common on subies and is doing it on mine...try some of that Gunk oil treatment and Rislone with next oil change, it worked for mine.

//marcus
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Old 11-10-2003, 05:33 PM   #4
slowme
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NicEJ25: It's not as loud at operating temperature...but still there.

marcus12: How long to you keep the additive in the oil and do I have to use it every oil change?
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Old 11-11-2003, 01:38 AM   #5
E Newman
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Piston slap is a big issue . The meaning of this problem is slamming side to side [tipping] movement of a piston when piston-to-cylinder clearance is excesive , can produce a very audible hollow , chattering sound . If that is happening , something like rings or play somewhere in the internal parts would be something to consider looking at . I say a better mechanic or one you can trust and get to the real problem . Your symptoms dont sound like " Piston Slap "

E Newman
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Old 11-11-2003, 01:55 AM   #6
SubaruImpreza_power
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It's Piston Slap.. both my Subaru's make the same sound.. Sounds almost like a diesel truck in the morning. It's due because of the way the Pistons are made in the H-4 The pistons are short so they wont run into the Rod.
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Old 11-11-2003, 07:55 AM   #7
slowme
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As per the dealer: "It's normal and to live with it." That was the same answer for two separate dealers. So it has to be normal, which I still can't believe. I hate that sound and if the car did it when I first looked at it, I would have skipped over it.

Any ideas of a good mechanic in Buffalo,NY?
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Old 11-11-2003, 03:04 PM   #8
E Newman
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Try a high performance mech . Dealers are nothing but BS , They tryed to charge me 200$ to change a CV boot , what a joke.

Well then good Luck
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Old 11-11-2003, 03:15 PM   #9
adeliciouspizza
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hey, i have the same issue. have a look at these two threads:

It's a knock knock knock knock that seems to run in harmony with engine speed....

Heavy knocking sound when motors cold

also have a look at this page, it explains the issue and made me feel a bit better.

im just wondering if there is anything that can be done to make it better? i was in georgia and north carolina last winter when it was about 20-30 degrees outside, with about 7k miles and it was completely quiet. now i am at 35k miles in florida and its making noises when its like 60 degrees outside. i guess its a given that things will loosen up and get louder with time but it just seems excessive. it sounds like there is a wood pecker in my engine bay sometimes.

edit: i tried to link up a couple other threads about this issue. hopefully someone really smart will chime in.

Last edited by adeliciouspizza; 11-11-2003 at 03:30 PM.
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Old 11-11-2003, 05:03 PM   #10
Machine Age Victim
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I have always had valve noise (most boxer engines do, listen to a Porsche) but I've been developing what sounds like a leaky exhaust gasket, same cadence as engine RPM's and louder under load. but it doesn't go away when hot (like most exaust gasket leaks, expanding metal) sound liek your problem?

-jeff

btw I run 20w-50 because I favor the gas peddle and it gets really hot in florida
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Old 11-11-2003, 05:16 PM   #11
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almost 30k on mine and it does exactly the same thing on cold startup but goes away as the engine warms up. The only thing I could recomend is to experiment with different oil viscosities. When I switched to M1 0w-40 I noticed that the noise didn't occure as often and when it did ocure, it wasn't as loud as it was with the 5W-30 I was running previously. This deffinately sounds like piston slap especially since its effected by different oil types. I wouldn't worry about it unless it doesn't go away as the engine warms up.

-- Ed
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Old 11-11-2003, 10:34 PM   #12
Pakin
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I guess I have the "normal knock".

So a piston slap is heard louder while a knock is more noticeable in the driver's cabin?

Because on my sound, it's barely noticeable outside, more noticable inside.

-paK +2
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Old 11-12-2003, 01:12 AM   #13
Equilibrium Tuning
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mine is also more noticable inside the cabin.

-- Ed
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Old 11-12-2003, 04:54 AM   #14
SubaruImpreza_power
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in my 1995 L impreza I can hear it more inside the car and more so if you put your head down near were the passanger puts his/her feet.
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Old 11-12-2003, 05:32 AM   #15
Equilibrium Tuning
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yep.. that's exactly where I hear the noise comming from as well!
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Old 11-12-2003, 07:50 PM   #16
marcus12
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Mine's noisy lifters...and it comes and goes with warmth...never completely, but it gets quieter when my car is all warmed up. I just use a bottle of Rislone in place of a quart of oil with every oil change and a little GUNK oil treatment every 3 weeks or so. Careful with that though...it tends to gum up your oil filter over time, so be diligent with oil changes. As mentioned by everyone else, Subarus make a lot of "noise" that is pretty normal for the most part. But if it's affecting the performance of your car, you should just bring it to a trusted mechanic for a professional opinion.

FYI, lifter noise is usually caused by a cracked / mis-shaped rubber seal and is a pretty easy fix when done professionally. I'm having mine replaced this weekend

hope that all helps, sorry for the lengthy post
//marcus
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