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Discussion Starter #1
Hello Everyone;

I know a bit about engines but I'm no mechanic so I'm not going to make an assumption that my engine has piston slap. I have been reading everywhere and I have come to the conclusion that the Lexus IS350 is a loose motor and has piston slap. My car has a very faint knocking noise when cold and goes away once the car is running at proper temp. I have already had the recall done for the cam gears so I know its not that. I have brought it to the dealership and they have said that nothing is wrong with my motor. I am just looking to get a definite answer one way or the other. I asked the dealer today if its common to have piston slap on these motors and they said no. Has anyone else experience piston slap and has anyone got the dealer to replace the motor due to this condition. I was thinking about using Redline Oil and hopefully that will help. Any help would be greatly appreciated.

Thank you.
 

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In the ~4 years I've been reading the 2IS forums I've not read of any genuine cases of piston slap, so it's not a design issue with the engine in general (not to say YOUR specific one might not have a real problem)

The cam gear issue is more a grind noise for maybe 10-30 seconds on start up (though some folks HAVE reported it coming back after being fixed).

Many folks think there's some kinda knock/tick going on from the sound of the direct injection system (which sounds like a diesel, since diesels use the same type of system), but they all do that and it's not piston slap (and doesn't go away when the car is warm either).


Easy solution here is to ask to test drive another IS350 on the lot and see if it makes the same noise or not from a cold start. If not you have evidence yours has a problem.
 

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Discussion Starter #4 (Edited by Moderator)
In the ~4 years I've been reading the 2IS forums I've not read of any genuine cases of piston slap, so it's not a design issue with the engine in general (not to say YOUR specific one might not have a real problem)

The cam gear issue is more a grind noise for maybe 10-30 seconds on start up (though some folks HAVE reported it coming back after being fixed).

Many folks think there's some kinda knock/tick going on from the sound of the direct injection system (which sounds like a diesel, since diesels use the same type of system), but they all do that and it's not piston slap (and doesn't go away when the car is warm either).


Easy solution here is to ask to test drive another IS350 on the lot and see if it makes the same noise or not from a cold start. If not you have evidence yours has a problem.
Yes probably a good idea. I left it at Lexus for 3 days straight and they said the service manager, a senior tech and a few other people listened to the motor and heard nothing. What makes me annoyed is that the problem started at 69, 500 miles (Warranty run until 70,000) I brought it to them and the problem has continued and the warranty has expired. Im not sure what I can do now.

In the ~4 years I've been reading the 2IS forums I've not read of any genuine cases of piston slap, so it's not a design issue with the engine in general (not to say YOUR specific one might not have a real problem)

The cam gear issue is more a grind noise for maybe 10-30 seconds on start up (though some folks HAVE reported it coming back after being fixed).

Many folks think there's some kinda knock/tick going on from the sound of the direct injection system (which sounds like a diesel, since diesels use the same type of system), but they all do that and it's not piston slap (and doesn't go away when the car is warm either).


Easy solution here is to ask to test drive another IS350 on the lot and see if it makes the same noise or not from a cold start. If not you have evidence yours has a problem.
I have heard the ticking you are talking about. Back left of the motor this is more of a piston slap sound. It goes away once warm. I wish I could record the sound. Maybe I will drop it off @ Lexus again.
 

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There is definitely some upper end block noise from the engine when it is very cold that goes away when it warms up,...I lovingly refer to it as the sound of carpenter tools in a crocus bag. During the summer here never hear it, only winter months.

Could be piston pin or piston slap, allot of clatter.

My daughter's RAV4 does the same thing in winter.

It runs well so I'm not too concerned,...yet :)
 

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Discussion Starter #6
I cant really hear the noise with the hood up I can normally hear it when its cold and I open the passenger door then I can hear under the motor that way.
 

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I've replaced the cam gears and still had problems with cars rattling on cold start up. I think the oil must drain out of the controllers over night or while sitting causing the top end to make a bunch of noise during the first few seconds of running. It goes away as soon as everything is up to pressure. Fyi, there will also be a ticking noise while cold from the passenger side of engine near the firewall because of the mechanical fuel pump that sits there. It usually gets quieter when warm also.
 

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The ticking sound is the injector pulses,...this is more of a muted clacking sound like a bearing not having enough lube on very cold start up, could be the VVTi gear mechanism or pistons,...not really familiar with this engine design.
 

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Discussion Starter #13
So I just did an oil change and went from regular oil to motul full synthetic and the engine noise has got worse. It honestly sounds like lower engine knock. Lasts until the engine starts to warm up.
 

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Sounds good.

Could it possibly be the transmission needing a flush? What would an oil test show?
It's physically impossible to flush the transmission.

It's a sealed unit with lifetime fluid.

Even dropping the pan only gets about 10-15% of the fluid in the system out.
 
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