Toyota 3.5L V6 piston slap?

<johngdole.TakeThisOut@hotmail.com> wrote in message
news:a2fda3fe-79ab-480a-8bb8-2b80aeab6a25@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.
>

The piston slap noise is not the result of relaxed piston-bore production
tolerances. The noise is the result of shorter piston skirts.
--

Ray O
(correct punctuation to reply)
 >> Stay informed about: Toyota 3.5L V6 piston slap? 

<johngdole RemoveThis @hotmail.com> wrote in message
news:a2fda3fe-79ab-480a-8bb8-2b80aeab6a25@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... RemoveThis @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
 >> Stay informed about: Toyota 3.5L V6 piston slap? 

On May 7, 9:21 am, "C. E. White" <cewhi....RemoveThis@removemindspring.com>
wrote:
> <johngd....RemoveThis@hotmail.com> wrote in message
>
> news:a2fda3fe-79ab-480a-8bb8-2b80aeab6a25@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....RemoveThis@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.
 >> Stay informed about: Toyota 3.5L V6 piston slap? 

This message is not archived
 >> Stay informed about: Toyota 3.5L V6 piston slap? 

"Scott in Florida" <MoveOn DeleteThis @outa.here> wrote in message
news:4kn32456pfn9kctce74jd5v1ukgpl5io4r@4ax.com...

> That can't be 'good' for an engine...
>
> I'm wondering if using synthetic oil would help keep damage to a
> minimum while the piston is slappin against the bore....

I run 5W30 synthetic in my Frontier. It made no difference in the
rapping sound on cold morning compared to conventional 5W30. A few
years back a lot of people in an Ford Expedition mailing list I follow
complained about 5.4L Ford engines and piston slap. Ford claimed it
would not hurt durability and based on what people say in that list
have reported over the years, I think it has proved to be true. Some
people in that list tried synthetic to combat the noise - some claimed
it made a difference in the noise, some didn't. I tend to think it
shouldn't. Two lines of thought - when really cold, synthetic is
likely to be less viscous than conventional oils of the same rating
(they should have the same viscosity at 0, but probably not at -10).
This could mean the synthetic oil won't provide as much of a cushion,
thereby increasing the noise. Or, that because the synthetic oil flows
better at really cold temperatures, it will coat the bores sooner and
help dampen the noise. My personal experience was that there was no
consistent detectable difference between a synthetic oil and a good
quality conventional oil. My last Expedition would do the rap very
briefly on cold NC mornings (but cold in NC is not really all that
cold). I played around with different viscosities, and sort of, kind
of, thought that maybe 5W30 Mobil 1 reduced the occurrence of the
noise compared to 0W20 Motorcraft synthetic blend, but honestly I
don't think it is provable.

Ed
 >> Stay informed about: Toyota 3.5L V6 piston slap? 

This message is not archived
 >> Stay informed about: Toyota 3.5L V6 piston slap? 

"Scott in Florida" <MoveOn.DeleteThis@outa.here> wrote in message
news:kou324htrq9miro2khoa52ucela2jf2q2u@4ax.com...

> Not the right time to ask this but.....
>
> I wonder if you used a block heater for a bit before start up....

It might actually make things worse....I wonder if the bores wouldn't
warm up more than the pistons, increasing the clearance, or maybe
because of the differential expansion rates reduce it. Might depend on
how cold it is outside and how powerful a block heater. Interestingly
my first Expedition actually came with a block heater, which I never
used. But then it never had a problem with piston slap in the 149,000
miles that I owned it.

> Playing the car stereo loud around here isn't a good idea. We have
> a
> law against stuff like that.....LOL

Well if you have really good sound insulation (like in a Lexus) you
probably shouldn't hear it anyhow. And if you have an egg better with
no sound insulation (like a 1992 F150 stripper with the 300 inline
six), then the other mechanical noises probably cover it up.

Ed
 >> Stay informed about: Toyota 3.5L V6 piston slap? 

This message is not archived
 >> Stay informed about: Toyota 3.5L V6 piston slap? 

"C. E. White" <cewhite3.DeleteThis@removemindspring.com> wrote in message
news:482209d8$1@kcnews01...
>
> "Scott in Florida" <MoveOn.DeleteThis@outa.here> wrote in message
> news:kou324htrq9miro2khoa52ucela2jf2q2u@4ax.com...
>
>> Not the right time to ask this but.....
>>
>> I wonder if you used a block heater for a bit before start up....
>
> It might actually make things worse....I wonder if the bores wouldn't warm
> up more than the pistons, increasing the clearance, or maybe because of
> the differential expansion rates reduce it. Might depend on how cold it is
> outside and how powerful a block heater. Interestingly my first Expedition
> actually came with a block heater, which I never used. But then it never
> had a problem with piston slap in the 149,000 miles that I owned it.
>
>> Playing the car stereo loud around here isn't a good idea. We have a
>> law against stuff like that.....LOL
>
> Well if you have really good sound insulation (like in a Lexus) you
> probably shouldn't hear it anyhow. And if you have an egg better with no
> sound insulation (like a 1992 F150 stripper with the 300 inline six), then
> the other mechanical noises probably cover it up.
>
> Ed
In 1994, I bought a new Jeep Grand Cherokee with a straight 6 and the piston
slap was consistently noisy and sounded like a diesel even after warmup. To
me, excessive noise usually means wear of some sort. If you shouted loud
enough, Jeep would extend the engine warranty to 100,000 miles.

Dave C.
 >> Stay informed about: Toyota 3.5L V6 piston slap? 

Excellent detail. This still points to excessive piston-bore
clearance. Maybe Ford fixed it by using the more expensive
hypereutectic pistons, which seems to be the case looking at Mahle
pistons clearance specs instead of the cheaper Aisin pistons
specifications.


On May 7, 6:21 am, "C. E. White" <cewhi....RemoveThis@removemindspring.com>
wrote:
> 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
 >> Stay informed about: Toyota 3.5L V6 piston slap? 

03-01-08, 06:27 PM
MD350
Join Date: Aug 2006
Location: MD

Still waiting on a recall on the new 6 speed transmission on the ES
that flares. The 3.5L engine piston slap on cold starts. Keep being
told the piston slap is normal

I will give them credit, they recalled the front driver side floor mat
because it jammed up the gas pedal. But, that was only after the
Federal Government did a full investigation and they were forced to do
so.
__________________
2007 ES 350 UL Package TP/Black
XM radio and 3M clear bra

2007 Honda Pilot EX-L (wife's)
 >> Stay informed about: Toyota 3.5L V6 piston slap?