Knock, knock, who's there? Piston slap, Thats who. (2 Viewers)

[r3run33]

ok if the problem is in fact the piston slap it is not repairable in cold weather the piston hits the side of the block because of its size; once the engine warms up there is less friction thus no noise. someone may explain this better then me but yes i dont think its a major problem. just try to warm up vehicle before bolting down the road in cold temps. there is someone one this board that has gone thru the whole process of trying to fix it but i dont think they got very far with toyota. anyone remember this???

 

[knorrena]

Sorry for the delay in getting this posted.

I have a few vidoes on picasa. It was not that cold last week, so the knocking was not as bad as I have heard it. This week is supposed to get really cold, around 0*F so I will take a few more videos then.

Here is the link to the videos:

Picasa Web Albums - Karl - 2009_02_23

I hope the link works as I have never linked a video this way before.

The chick that took my report was not clear in the work order so they did not wind up starting the truck until it was quite warm (a relative statement for the area i know) thus they did not observe any noise. I spoke with the service manager, in fact he called me under his own volition. I explained the problem to him and he asked to have the truck in again. I have arranged to drop it off there again this week.

On another note I had the truck aligned while there because it was almost as darty as my 80. It drives much better now.

 

[Liam]

Sorry for the delay in getting this posted.

I have a few vidoes on picasa. It was not that cold last week, so the knocking was not as bad as I have heard it. This week is supposed to get really cold, around 0*F so I will take a few more videos then.

Here is the link to the videos:

Picasa Web Albums - Karl - 2009_02_23

I hope the link works as I have never linked a video this way before.

The chick that took my report was not clear in the work order so they did not wind up starting the truck until it was quite warm (a relative statement for the area i know) thus they did not observe any noise. I spoke with the service manager, in fact he called me under his own volition. I explained the problem to him and he asked to have the truck in again. I have arranged to drop it off there again this week.

On another note I had the truck aligned while there because it was almost as darty as my 80. It drives much better now.

to me, and i am no expert, it doesnt sound like an exhaust leak. I've heard a few LC have the manifold issue and it never sounded "wobbly", if that makes sense....

 

[e9999]

darn, sounds like an 80...
definitely way louder and not as smooth as our 100, although the latter admittedly in balmier climates, sorry....

 

[hoser]

I would PM LexusBen and ask him to listen to vid.

 

[dclee]

That seems very similar to what mine sounds like, but oddly enough, it's smooth when in Park or Neutral. The "diesel engine" noise only starts once I put the truck into gear. Granted, putting it in gear causes the RPMs to change, so maybe it's just RPM-based, but that sounds weird if it's actually piston slap.

 

[SWUtah]

What does it sound like "inside" the Lexus? I bet most don't notice since the truck lives in the garage and is warmer when started and or they have the radio on and don't here the sound. Problem has been around for years. Traced back to the booring machine getting out of spec during engine block production and also the shorten skirt and lighter pistons. With every run of blocks some are bored when the engine machine gets a little out of spec. I got this info several years ago and posted it somewhere on here. I think my name on here back then was Pitbull??? Good luck I have never heard of Toyota/Lexus doing anything about it. Just turn up the heat in your garage. Keep us posted.

 

[Topoguide]

Yep, sounds like the piston slap to me (although not a technician). Mine sounds the same, and does get much louder when it gets really cold, like below 0 deg F (not here btw).

As for why it is louder in gear, it should be due to the motor being under a load thus making it sound louder. If you were to accelarte prior to warm up it should be even louder still.

As far as what it sounds like in the cabin, I did not hear mine until one day my wife got in right after I started the motor. After that I noticed it more regularly, and then on a trip to Utah in cold weather I eperienced the full diesel sound.

Also, I noticed a post of thicker oil reducing the sound. That is great it worked for your buddy. The theory behind using syn oil with a lower viscosity is to get better lubrication during the time of warm up thus reducing wear and hopefully noise. You could put straight 50 SAE in it and your noise would most likely be reduced a bit quicker, but the motor would wear quicker over the long term. Although since no-one has studied this specific to the piston slap it is really all speculation based on studies under normal conditions.

One thing for sure is after this thread I don't feel so alone. I was begining to think perhaps I should go join the Tundra forum and put a disguise on my Cruiser