Light Knock at Idle

Heads, valves, pistons, rods, crankshaft, etc...

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Minglor
In Neutral
Posts: 7
Joined: Sat Oct 06, 2007 5:55 am

Light Knock at Idle

Post by Minglor »

I have a very light knock sound at idle.
This is only when the car is warm and has been driven for a bit.

My idle is a touch low close to 600 rpms.
and if I bring the rpms up the sound disappears

Not present on startup / when the car is cold.

It doesn't sound like rod knock mainly going by what this sounds like.
http://www.youtube.com/watch?v=-G6_4wzAETM
I have no smoke or anything and the car runs very smooth.

Suggestions or Ideas as to what this could be?
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ericem
Fifth Gear
Posts: 3242
Joined: Mon Oct 16, 2006 9:44 pm
Location: Toronto,ON Canada

Post by ericem »

Lifters sticking. Try some seafoam in the oil and do a oil change after 10 minutes of driving. I did that was gone for good :D
1993 Subaru Legacy L AWD Wagon R.I.P
1994 Subaru Legacy SS R.I.P :(
2004 Nissan Titan LE 4X4
2007 Subaru Legacy GT :)
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tris91ricer
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Location: Valdosta, GA

Post by tris91ricer »

My guess exactly! At least change the oil, guy. It'll solve itself.
[b]'92 L Sedan[/b]
EJ20g 4.11 5sp LSD

[quote]e46 owners tend to be twats.
[/quote]
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Minglor
In Neutral
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Joined: Sat Oct 06, 2007 5:55 am

Post by Minglor »

hmmm.

I only noticed it after I changed my oil. But I never gave it a good listen before this, mainly because I got the car.

I will seafoam the oil and go with a different weight and synth.

Thanks for the input guys.
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thehookeup
Third Gear
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Location: portland OR

Post by thehookeup »

is it a tick or a knock?
-93 2.2T (RIP), 93 N/A best car on earth.
-00 legGT, 18" PIAA sport mesh wheels, front/rear Rallitek sways, lowered whitelines, coming soon: 2.5L sti internals, 20g heads P&P, twin charged. motor is almost ready to go in.
Andrew
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Minglor
In Neutral
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Joined: Sat Oct 06, 2007 5:55 am

Post by Minglor »

thehookeup wrote:is it a tick or a knock?
Seems to be easier to hear from the front under the car.
I would venture to guess a knock.
but very hard to pick out over engine noise.
could just be drivetrain noise.
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Kelly
Fourth Gear
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Joined: Sat Nov 01, 2003 5:35 pm

Post by Kelly »

You need one of these.

Image


Is it coming from the middle of the motor, or out on the heads.
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