Toyota 3.5L V6 piston slap? [Toyota]

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From: johngdole on 6 May 2008 21:26

Graybeard's experience with other Lexus on the lot and Toyota suggests
the relaxed piston-bore production tolerance is common on the 3.5L
V6.

How about on the Camry V6/Avalon? Anyone?

From: "Graybeard" <graybear...(a)cfl.rr.com>
Date: Mon, 28 Apr 2008 10:04:01 -0400
Local: Mon, Apr 28 2008 7:04 am
Subject: Reply from Lexus

The following is the reply from Lexus in response to the "piston
slap"
noise that we hear from our ES350 and also from a randomly selected
car on
the dealers lot.

Graybeard

Subject
Defective Lexus Design

Discussion Thread
Response (Heather Mauu) 04/28/2008 06:34 AM

Thank you for contacting the Lexus Customer Satisfaction
Department
regarding Concern. We appreciate the time you have taken to share your
thoughts.

Lexus understands your concerns with the engine noise heard in
your
2007 ES 350, Vehicle Identification Number JTHBJ46G772142795. Lexus
has done
thorough research into this matter and has found that this engine
noise is a
normal operating condition. We apologize that the vehicle has not met
your
expectation. Please be assured that your dissatisfaction has been
documented
in our records for product improvement consideration.

If you require further assistance, please contact the Lexus
Customer
Satisfaction Department at
1-800-255-3987, Monday through Friday, 5:00 a.m. to 6:00 p.m.,
or
Saturday, 7:00 a.m. to 4:00 p.m., Pacific Standard Time.

Sincerely,

Heather Mau'u
Customer Satisfaction Representative

From: ransley on 6 May 2008 23:03

On May 6, 8:26 pm, johngd...(a)hotmail.com wrote:
> Graybeard's experience with other Lexus on the lot and Toyota suggests
> the relaxed piston-bore production tolerance is common on the 3.5L
> V6.
>
> How about on the Camry V6/Avalon? Anyone?
>
> From: "Graybeard" <graybear...(a)cfl.rr.com>
> Date: Mon, 28 Apr 2008 10:04:01 -0400
> Local: Mon, Apr 28 2008 7:04 am
> Subject: Reply from Lexus
>
> The following is the reply from Lexus in response to the "piston
> slap"
> noise that we hear from our ES350 and also from a randomly selected
> car on
> the dealers lot.
>
> Graybeard
>
> Subject
> Defective Lexus Design
>
> Discussion Thread
> Response (Heather Mauu) 04/28/2008 06:34 AM
>
> Thank you for contacting the Lexus Customer Satisfaction
> Department
> regarding Concern. We appreciate the time you have taken to share your
> thoughts.
>
> Lexus understands your concerns with the engine noise heard in
> your
> 2007 ES 350, Vehicle Identification Number JTHBJ46G772142795. Lexus
> has done
> thorough research into this matter and has found that this engine
> noise is a
> normal operating condition. We apologize that the vehicle has not met
> your
> expectation. Please be assured that your dissatisfaction has been
> documented
> in our records for product improvement consideration.
>
> If you require further assistance, please contact the Lexus
> Customer
> Satisfaction Department at
> 1-800-255-3987, Monday through Friday, 5:00 a.m. to 6:00 p.m.,
> or
> Saturday, 7:00 a.m. to 4:00 p.m., Pacific Standard Time.
>
> Sincerely,
>
> Heather Mau'u
> Customer Satisfaction Representative

I thought issues like that were a thing of the past, from before
computer controlled machining.

From: Ray O on 7 May 2008 00:58

From: C. E. White on 7 May 2008 09:21

<johngdole(a)hotmail.com> wrote in message
news:a2fda3fe-79ab-480a-8bb8-2b80aeab6a25(a)v26g2000prm.googlegroups.com...
> Graybeard's experience with other Lexus on the lot and Toyota
> suggests
> the relaxed piston-bore production tolerance is common on the 3.5L
> V6.

Piston slap is common on lots of engines these days. In an attempt to
maximize fuel economy, engineers have worked to reduce piston to bore
friction. This has been done by reducing the piston's skirt length
(think height of the piston) and optimizing the piston to bore
clearance for a warmed up engine. The 3.5L V6 has aluminum pistons and
iron liners. They expand at different rates, plus the pistons are no
cooled directly, so they run hotter than the bores. Since aluminum
expands at a higher rate than iron (steel), the piston to bore
clearance is greater when the engine is cold. This increased clearance
along with the shorter skirt allows the piston to rock slightly in the
bores. As a piston passes top dead center and bottom dead center the
trust angel of the rods change direction. This causes the piston to
shift angles in the bore. The pistons shift so that the bottom of the
skirt swings from one side of the bore to the other (opposite side of
the piston now rides against the bore). If the piston is slightly
loose in the bore, the piston can build up enough speed during this
shift that it strikes the opposite side of the bore with enough force
to generate an audible noise. Many older engines (including Toyota
engines) had so much lifter and chain clatter that you could not hear
this noise, even if it was present. And many older engines ran tighter
clearances, which reduced the noise when the engine was cold, but
increased friction and hurt fuel economy. And many older engines had
longer piston skirts that limited the piston's angle changed, but the
longer pistons were heavier and had higher friction, again decreasing
fuel economy.

I think every manufacturer is hearing complaints about piston slap.
Even with really good machining techniques, there is some variation in
piston to bore clearance. When you are trying to run at the perfect
clearance, a few are going to miss. In general if the piston slap
noise goes away shortly after you start a cold engine, it is nothing
to worry about. If the noise persist after the engine is warm, you
probably need to have an expert check it out. It might not be piston
slap at all.

> How about on the Camry V6/Avalon? Anyone?

Same basic engine. I would expect it to behave in the same manner.
This is really nothing new. A couple of years back when I was shopping
for a pick-up I test drove three V8 Tundras. All three exhibited
marked piston slap noise when started. The salesman told me they all
did that and not to worry. Interestingly Ford replaced thousands of
engine for this same concern - I guess Ford owners just weren't used
to the rap rap rap of quality. I did not buy a Tundra in the end. I
ended up with a Nissan Frontier - which makes the piston slap noise on
cold morning....errrrrrrrr. I've learned to live with it.

Ed

> From: "Graybeard" <graybear...(a)cfl.rr.com>
> Date: Mon, 28 Apr 2008 10:04:01 -0400
> Local: Mon, Apr 28 2008 7:04 am
> Subject: Reply from Lexus
>
> The following is the reply from Lexus in response to the
> "piston
> slap"
> noise that we hear from our ES350 and also from a randomly selected
> car on
> the dealers lot.
>
> Graybeard
>
> Subject
> Defective Lexus Design
>
> Discussion Thread
> Response (Heather Mauu) 04/28/2008 06:34 AM
>
> Thank you for contacting the Lexus Customer Satisfaction
> Department
> regarding Concern. We appreciate the time you have taken to share
> your
> thoughts.
>
> Lexus understands your concerns with the engine noise heard in
> your
> 2007 ES 350, Vehicle Identification Number JTHBJ46G772142795. Lexus
> has done
> thorough research into this matter and has found that this engine
> noise is a
> normal operating condition. We apologize that the vehicle has not
> met
> your
> expectation. Please be assured that your dissatisfaction has been
> documented
> in our records for product improvement consideration.
>
> If you require further assistance, please contact the Lexus
> Customer
> Satisfaction Department at
> 1-800-255-3987, Monday through Friday, 5:00 a.m. to 6:00 p.m.,
> or
> Saturday, 7:00 a.m. to 4:00 p.m., Pacific Standard Time.
>
> Sincerely,
>
> Heather Mau'u
> Customer Satisfaction Representative

From: ep45guy on 7 May 2008 13:07

On May 7, 9:21 am, "C. E. White" <cewhi...(a)removemindspring.com>
wrote:
> <johngd...(a)hotmail.com> wrote in message
>
> news:a2fda3fe-79ab-480a-8bb8-2b80aeab6a25(a)v26g2000prm.googlegroups.com...
>
> > Graybeard's experience with other Lexus on the lot and Toyota
> > suggests
> > the relaxed piston-bore production tolerance is common on the 3.5L
> > V6.
>
> Piston slap is common on lots of engines these days. In an attempt to
> maximize fuel economy, engineers have worked to reduce piston to bore
> friction. This has been done by reducing the piston's skirt length
> (think height of the piston) and optimizing the piston to bore
> clearance for a warmed up engine. The 3.5L V6 has aluminum pistons and
> iron liners. They expand at different rates, plus the pistons are no
> cooled directly, so they run hotter than the bores. Since aluminum
> expands at a higher rate than iron (steel), the piston to bore
> clearance is greater when the engine is cold. This increased clearance
> along with the shorter skirt allows the piston to rock slightly in the
> bores. As a piston passes top dead center and bottom dead center the
> trust angel of the rods change direction. This causes the piston to
> shift angles in the bore. The pistons shift so that the bottom of the
> skirt swings from one side of the bore to the other (opposite side of
> the piston now rides against the bore). If the piston is slightly
> loose in the bore, the piston can build up enough speed during this
> shift that it strikes the opposite side of the bore with enough force
> to generate an audible noise. Many older engines (including Toyota
> engines) had so much lifter and chain clatter that you could not hear
> this noise, even if it was present. And many older engines ran tighter
> clearances, which reduced the noise when the engine was cold, but
> increased friction and hurt fuel economy. And many older engines had
> longer piston skirts that limited the piston's angle changed, but the
> longer pistons were heavier and had higher friction, again decreasing
> fuel economy.
>
> I think every manufacturer is hearing complaints about piston slap.
> Even with really good machining techniques, there is some variation in
> piston to bore clearance. When you are trying to run at the perfect
> clearance, a few are going to miss. In general if the piston slap
> noise goes away shortly after you start a cold engine, it is nothing
> to worry about. If the noise persist after the engine is warm, you
> probably need to have an expert check it out. It might not be piston
> slap at all.
>
> > How about on the Camry V6/Avalon? Anyone?
>
> Same basic engine. I would expect it to behave in the same manner.
> This is really nothing new. A couple of years back when I was shopping
> for a pick-up I test drove three V8 Tundras. All three exhibited
> marked piston slap noise when started. The salesman told me they all
> did that and not to worry. Interestingly Ford replaced thousands of
> engine for this same concern - I guess Ford owners just weren't used
> to the rap rap rap of quality. I did not buy a Tundra in the end. I
> ended up with a Nissan Frontier - which makes the piston slap noise on
> cold morning....errrrrrrrr. I've learned to live with it.
>
> Ed
>
>
>
> > From: "Graybeard" <graybear...(a)cfl.rr.com>
> > Date: Mon, 28 Apr 2008 10:04:01 -0400
> > Local: Mon, Apr 28 2008 7:04 am
> > Subject: Reply from Lexus
>
> > The following is the reply from Lexus in response to the
> > "piston
> > slap"
> > noise that we hear from our ES350 and also from a randomly selected
> > car on
> > the dealers lot.
>
> > Graybeard
>
> > Subject
> > Defective Lexus Design
>
> > Discussion Thread
> > Response (Heather Mauu) 04/28/2008 06:34 AM
>
> > Thank you for contacting the Lexus Customer Satisfaction
> > Department
> > regarding Concern. We appreciate the time you have taken to share
> > your
> > thoughts.
>
> > Lexus understands your concerns with the engine noise heard in
> > your
> > 2007 ES 350, Vehicle Identification Number JTHBJ46G772142795. Lexus
> > has done
> > thorough research into this matter and has found that this engine
> > noise is a
> > normal operating condition. We apologize that the vehicle has not
> > met
> > your
> > expectation. Please be assured that your dissatisfaction has been
> > documented
> > in our records for product improvement consideration.
>
> > If you require further assistance, please contact the Lexus
> > Customer
> > Satisfaction Department at
> > 1-800-255-3987, Monday through Friday, 5:00 a.m. to 6:00 p.m.,
> > or
> > Saturday, 7:00 a.m. to 4:00 p.m., Pacific Standard Time.
>
> > Sincerely,
>
> > Heather Mau'u
> > Customer Satisfaction Representative- Hide quoted text -
>
> - Show quoted text -

Excellent and informative reply - thank you.

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