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Knock at start up?

Just like the title says, when I first start my car it has a noticeable knock sound until it warms up then I don't hear it. My car go through oil kinda bad. I just ordered an oil cap, I also know the seals on the turbo are no good. The car does not smoke or leak oil, but I will have to add a quart almost every other week. Any ideas?
 

It has 3g lifters, and it's a knock not a tick. I'm just wondering why it goes away when it warms up?
 

AnotherNewb

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Apr 25, 2010
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Almost sounds like a wrist pin. Once the aluminum in the piston warms up it expands and takes up the play.
 

AnotherNewb

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Try this... on a cold start when it knocks, try pulling plug wires one by one until the knock disappears. Narrows it down to the cylinder with the knock.
 

PreskitVR4

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Jun 28, 2008
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Prescott, Northern AZ
^^^^^^BTW, if it goes away it's prob a rod bearing issue; although I've never heard of that going away afta warmup.
 

AnotherNewb

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Which is why I suggested a wrist pin. Aluminum expands more than steel or iron will at a lower temp.
 

Olson

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Oct 7, 2006
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Moreno Valley CA
Quoting PreskitVR4:
^^^^^^BTW, if it goes away it's prob a rod bearing issue; although I've never heard of that going away afta warmup.


Happened to me, now I'm rebuilding a motor with a spun bearing
 

galant344

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Sep 23, 2006
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oakforest il.
what kind of pistons are in the car? could be wrist pin noise but i thought that doesn't go away when the engine is warm either? I know piston slap can go away when the engine warms up.
 

I was listening to my car at start up and noticed the sound seems to be in the back of the motor where the balance shafts are. Is it possible for a balance shaft to make a knocking sound?
 

AnotherNewb

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Yes it is. I have a 6bolt motor in a talon right now that has a balance shaft knock, only when I got it it was really bad. Kinda laborous but you can pull the timing belt and connect a drill to the oil pump pulley, that's how I found mine.
 

Balance shaft will do that to you. I rebuild 2 bottom ends last season for what they thought was a rod knock. It was a spun bearing at the rear balance shaft that the bearing fell into the oil pan. pull the pan and front over off, and double check. A great time for a BSE kit.
 

Ehhh, I pulled the plug wire out of cylinder #4 and the knock stopped. /ubbthreads/images/graemlins/frown.gif That's no good...
 
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