Sienna Engine Sludge Problem

if you do a search on toyota sienna in this forum, you will see some posts indicating sludge issues as late as 04. Thats what I was referring to.

I have no problems with a toyo. I owned a 1987 camry for 15 years and had absolutely no problems.

Maybe I an naive but how can ppl not change oil a required?

The Toyota sludge problem involved LESS than 1% of six cylinder engines built between 1997 and 2001, but ANY engine of ANY make can develop sludge or gelling if oil changes are not done at an "appropriate" time.

The problem has been, owners don't know WHEN to change oil based on their driving pattern. A person driving only two miles a day in cold weather should change oil every 2,000 miles, or 3,000 miles at the outside. A person who drives a hundred miles per day on the highway at 60 mph could go 8,000 miles between oil changes.

GM has put a monitor in their recent models that tracks usage patterns. The "one mile a day" driver will see their oil change light come on after only 2,000 or 3,000 miles. The 100 mile a day driver won't see the oil change light until 8,000 miles or 10,000 miles. But, for Toyota owners, the best rule is every 3,000 miles for "short trip only" drivers, and every 5,000 miles for mixed local/highway driving.

Are you saying that care of a Toyota has to be different from other brands????

Motor oil behaves in consistent ways. GM studied motor oil behavior in each of its engines to design its oil monitor system. The studies showed that short trips (under four or five miles) in cold weather, or towing a trailer in hot weather or mountains required oil changes every 2,000 to 3,000 miles; short trips in warm weather required oil changes every 3,000 to 4,000 miles; the mixed short trip/highway driving required changes every 5,000 to 7,000 miles, and driving at cruising speeds on the highway (but NOT towing) enabled oil to last up to 10,000 to 12,000 miles.

But, oil behaved slightly differently in each GM engine, so GM calibrated its oil monitor differently for each engine.

Toyota does NOT have an oil monitoring system in any of its current vehicles. That means that Toyota owners need to be their OWN monitor and pay attention to their driving patterns. And, they need to pay attention to their warranty requirements.

My 2001 Toyota, with 305,000 miles on the engine, is still under Toyota's extended warranty for vehicles covered by the oil sludge class action suit settlement. That Toyota extended warranty requires changing the oil every 5,000 miles except in non-severe highway driving, which allows changes at 7,500 miles.

So, the "conservative" thing for Toyota owners to do to protect their warranty coverage is to change every 3,000 miles if most of their driving is trips of less than five miles, and change at 5,000 miles if their driving is a mixture of short trips and highway driving. That way, they have clearly met or exceeded the requirements of the Toyota warranty.

What about synthetic oils? Many people like to use expensive synthetic oils, such as Mobil I. And, these are great oils. Yet, every engine warranty that I have read has EXACTLY the same oil change requirements for synthetic oil as for generic oil. A friend of mine just bought a Suburu.

The Subaru warranty makes clear that the oil should be changed at 3,500 miles in severe use (short trips) and at 7,500 miles in routine use (highway trips). But, the warranty specified that the oil change requirements are the SAME for synthetic oil as for conventional oil.

The GM engine warranty requires changing the oil when indicated by the oil change monitor...which could be anytime between 2,000 miles and 10,000 miles.

The sludge problem occured with LESS than 1% of Toyota engines built between 1997 and 2001. There have been ZERO documented and proven cases of a Toyota engine built after 2001 that was PROPERLY maintained having a sludge problem...precisely ZERO.

According to the massive Consumer Reports data base of surveys of vehicle owners, the Toyota's built between 1997 and 2001 match Honda as being the MOST reliable vehicles built in that era...no American built van or mini-van comes close.

If you are buying any used vehicle, you should have it inspected by a good technician. A fifteen minute inspection will easily discern whether or not a vehicle has any sort of sludge problem.

The vehicles of any brand that are most likely to have engine problems are those with one particular usage pattern: used ONLY for trips of less than five miles, especially in cold temperatures. Such vehicles never get fully warmed up and so engine blow-by products built up in the oil and begin to destroy the engine. If an engine is fully warmed up, such by-products are burned off.

So, ironically, a used vehicle with 100,000 miles that was used exclusively for highway driving will have an engine in MUCH better condition than a vehicle with just 20,000 miles that was used exclusively for trips of just one or two miles each...the "grandma driving to church" vehicle.

The grandma who drives her car ONLY one or two miles a day needs very frequent oil changes...every 2,000 or 3,000 miles at the outside.

alanhouston,

Okay, I'm glad I returned to check this thread out again, so I could respond to this, cause here we go again with this "absolutely or precisely ZERO" proven cases CRAP!!

My van was a 2003 and it still had the problem. I don't know about proof, but what I had to present to the dealership was enough for them to agree to completely rebuild the engine again at 32K miles. I had enough receipts and a log of everything that I had done that they told me that I appeared to have done proper maintenance. And just how the hell does anyone prove this anyway. Would you have to have a video of the inside of your engine which shows the sludge slowly building up. And dated videos of yourself changing the oil.

I had well over 200K miles on my first Tacoma and I'm approaching 190K with my second, and I've had no problems with either of those. So tell me why I would pay less attention to the vehicle that my precious family rides in the most.

I guess it's easy to sling these factual statements about if it hasn't happened to you. If it's a small percentage, I'm happy about that. And I'm glad that there are a good number of you that have had no problems. Thanks for sharing, but it does little to ease my pain about the one I had :)

I'm not going to picket anyone's dealership or anything like that, but I firmly believe that the problem existed beyond 2001. Even though I own another one now, the deal for it had to be extremely good for me to do it. And even with the deal, without some guarantee that they'd cover the engine, I would have bought an Odyssey - at least I can give them their chance too!! Maybe next time.

Proman,

Yeah, the oil change for life does sound too good to be true, doesn't it. I do have documentation for both the oil and the engine guarantee, but I'm realistic too. What happens if the dealership goes under - who's going to fulfill my guarantee? I don't know. I just know that this particular dealership has been around for a long time, so I feel comfortable about it, but I know that nothing is for certain.

To everyone, I don't know why people keep stating this "zero proven cases" stuff. Maybe they have a stake in Toyota or something. I don't have a stake in the game either way - my deal is done with it, so I could care whether the sludge thing was true or not. I'm just telling you that I've experienced it, so it is real.

I remember I read an article regarding the sludge formation. It has little to do with what kind of oil you are using, but how dirty the oil gets. The contaminants are mostly by-products of combustion, blow-bys, etc. When the oil get saturated with these stuff and if the temperature is boiling the oil, it can form sludge.

I heard that Toyota re-designed the engine breathing system (breathing tube, pcv, etc.) and mis-calculated the rate of breath the engine needs, so the contaminants accumulates much faster than what they expected, hence the oil got saturated way before the oil change interval of 7500 miles. And, the new design also raised the temperature to achieve ULEV requirement. So, dirty oil boiling, that's why the sludge problem is so popular among this engine, but not others.

And, of course, you can tell now, to prevent the sludge, you have to prevent the oil from getting saturated with the dirty stuff. That means, change the oil more frequently than specified in the manual. What I do is change oil every 3000 miles, not specific to just this car, but all the cars in my household for the past 15 years.

And from my experience, it seems that if the engine is running on cleaner oil, it's less likely it will develop any other problems, especially related to emissions.

There should be no reason to treat the Sienna engine any differently than other similar engines. The fact that there is even a topic on this matter pertaining to the Sienna (or Avalon) means that there is a problem.

Why should I purchase a vehicle that requires special attention to keep it up and that if I don't I'm SOL??? Why??

To make a long story short, I bought a 2003 Sienna at the end of July 2003. It developed a sludge problem at 32K in 2005. Because I had oil change documentation they fixed it all at their cost.

I found evidence that Toyota had sent letters to previous owners about this problem warning to change oil more frequently. Because of the time I bought, I never received the letter. But I have been changing the oil religiously myself.

Now at 111,000 miles the oil light comes on. I had just checked the oil the day before and all looked good. In the end, the dealership found that the seal in the back was gushing oil. The dipstick always showed that a good amount of oil, so maybe gushing is a relative thing. I had smelled burning when the oil light came on though it it smelled more electrical than oil. They did say that in removing the valve cover, everything was as clean as a whistle there.

Anyway, they wanted to drop the transmission and do the seal, timing belt, etc. to the tune of $3000.00. When they were done, the oil light still came on and they wanted to check the bearings to the tune of another $2500.00. I put the brakes on at that point.

So they offered to cut my repair costs thus far in half if I agreed to buy another Sienna from them at a reduced cost and a few grand for my current Sienna.

I did my homework and found that what they were offering up front did not include all incentives. I stated that I did not want to haggle and if they would just provide me with their bottom line offer, I'd shop around (including looking at Odysseys). Before I left the dealership, they had given me two other bottom line offers :smooch: It's a bummer that they did not do that right away when knowing my situation.

Anyway, I'm still thinking that the first overhaul at 32K may have contributed to this situation.

Any comments from owners of 2004-2009 Sienna owners about your experiences?

Wow! This is a long running thread!!

Thanks.


I have a 2004 Limited with 135,000 miles on the clock and counting......and so far so good! (knock on wood!) I have done all repairs and oil changes myself except for the radiator recall. Oil changes get done at 5,000 miles and no sludge that I can see. Still runs like new...no smoke or anything unordinary. I'd say go for it! Buy one! It hasn't been 100% problem free, but I have nothing to complain about.....most any vehicle with this many miles is going to need something fixed on occasion. I've had Camry's for the last 20 years and as hard as they are to beat, this van is fantastic as far as I am concerned!

Just a quick fact about sludge formation from working on engines more than 35 years minimum.

There are basically 2 types of drivers.

They can have the same vehicle, same milage, same climate.

Driver one never has sludge.

Driver two always has sludge.

Here's why.
I ride with the person in a 2 mile circuit, then back.

Driver two,
He drives the vehicle like a steam ship.
Never gets the vehicle up to speed, lugging along, holding up traffic.
This persons engine never gets to a oil moisture burn off.

He gets back home in short trip from the drug store, and sure enough
a little more moisture as steam has settled to the bottom of the oil.
All set to get mixed in again.

This is the slime on the bottom of oil fill cap that tried to get out.
But it never got hot enough to vapor out as steam.

Driver one,
He sprints down the road, and can't wait to get to freeway speed.
He's the A type that likes to drive & pays attention to details.

He started out by letting the engine warm up 5 minutes before putting it in gear.
This also transfers heat to the transmission so it has a better life.

**
Now that's it's darn cold now,
moisture will settle in very quickly as the engine cools.

If you could place a window on the side of the engine to see inside when the temp drops below freezing,
you would see the inside completely covered in frost everywhere to the line of the oil level.

As soon as the engine starts, the oil has to deal with the moisture and it's mixed in again.
It then tries to burn it off before the next cycle begins again.

If you never made soap, this is how it's made. Oil & Water.

These are high tech engines that produce power efficiently .
They can't do everything, so you need to help if not kept in heated garage, by adding engine heater if your in this zone.

This sludge thing has been going on since the model T.
I have watched these reports with Toyota for years.

If you ever had an over heated issue with loss of coolant, your
engine will have a short life period, even if the repair is made.
This is any vehicle, any manufacturer.

Ask any aircraft pilot,
What's the first thing he does before ever getting in to start the engine?
OK, I'll tell ya, but you can easily find out.
He gets out the tool to remove moisture that settled to the bottom of the wing fuel tanks. Every time without fail.

Moisture kills engines and fuel systems.
If the moisture is never removed from a stored engine, it will rust solid.
I have tried to restore this scene before, and with sledge hammers pounding on the pistons, they would not budge.

Happy Trails, and try not to torture your Toyota.

I am FAR from an expert on the engine sludging issue.....
I have a couple of theories that I would like to share.

First.....I have a 2003 Sienna with a build date of 10/2002.
I have the "more recent" version of the PCV valve.....which I have shown in this picture.
http://rides.webshots.com/photo/2625170610011220610ZVriEr

As you can see.....it is a metal version.....that threads into the metal of the rear valve cover.
I think that this is one of the changes that TOYOTA made.

Another change that has already been mentioned is the baffels inside the valve covers.
I have found a couple of pictures on the internet of the inside of the valve cover.....showing these baffels.
The stated change was to improve the routing for the liquid oil to drip back down.
Now.....from looking at the pictures that I have seen there is not enough room above the baffels to hold much oil.....they are welded to the inside of the cover.....at the very top.
The baffels cover the PCV valve (rear valve cover) and the breather (front valve cover).
Now......the PCV system LOOKS to me (a non-mechanic, non-expert) like a healthy system.
HOWEVER, my theory is that crud may build up between the baffel and the valve cover......perhaps blocking or at the least, restricting the PCV flow.
This would certainly contribute to a buildup of "nasties" in the oil that would lead to sludging.

The pictures that I have seen on the internet that show "sludged" or "Gelled" motors have the crud pretty much everywhere......so it is unlikely that the area above the baffels is clean.
However, that the PCV system becoming restricted is ONLY my uneducated THEORY.

Most of the oil that would be getting up above the baffel would be getting there in vapor form....and condensing back into fluid.

Now.....fresh air enters the front valve cover.....and the contaminated air exits the rear valve cover......so all other things being equal......it is possible that you would have more chance of buildup starting in the rear valve cover.....above the baffel.

My 2003 Sienna had 5000 mile Oil changes with "synthetic".....and I replaced my PCV valve......the factory original one.
The original one was not clogged, but I did see a buildup around the opening into the valve (the part that sticks into the valve cover).
This, plus looking at the pictures has given me the theory that I mention.

So.....perhaps it would be wise for us to pay attention to.....and periodically verify flow through the PCV system.
Those who have the press-in version of the PCV valve could just pull theirs out to inspect the valve.......the screw-in version is more difficult to remove......as it has a thread lock on the threads......so it is not a simple loosen and unscrew.....need to use the wrench almost the whole way.
However......if I am correct......it is worth keeping a check on.

Now, if one were to have their valve covers off......they could clean the inside of them using a solvent cleaner, like Berryman's B-12 Chemtool.
As you would be draining almost all of it out....and letting almost all of it evaporate before putting the valve covers back onto your motor......no worries about solvent inside the motor.

I have found a couple of pictures on the internet of the inside of the valve cover.....showing these baffels.
Would of liked to see those.


Now.....from looking at the pictures that I have seen there is not enough room above the baffels to hold much oil....I think the purpose is to not hold any oil, but condense the vapor of oil & on the cooler plates before it escapes out as vapor.

The moisture is as well, but the small amount of water as steam each cycle hopefully has vented.



HOWEVER, my theory is that crud may build up between the baffel and the valve cover...
And your correct. I have seen it from servicing some applications.


This would certainly contribute to a buildup of "nasties" in the oil that would lead to sludging. This is the result of short trips and low heat output. This could be aggravated by faulty cold running thermostat as well.

When the engine gets to a coolant temp of 200, it becomes less of an issue.

Here again, some people turn the key, and off they go.
I never do this, because it's torture when below 20 degrees, and more so below zero.

Mine is running while getting dressed.
I want the tranny getting warmed up as well.
I want heat warming the interior before climbing in.



Now.....fresh air enters the front valve cover.....and the contaminated air exits the rear valve cover......so all other things being equal......it is possible that you would have more chance of buildup starting in the rear valve cover.....above the baffel.Engine vents, if applied are simply a port for balanced pulsed air from piston movement. This helps from seals leaking oil if pressure inside engines was greater than ambient air pressure.

You can feel this pulse of piston movement with engine running and then remove oil fill cap, and place your hand over the opening.

The PVC valve is only a momentary device depending on engine manifold pressure whether at idle or wide open throttle.
It's not always in effect. If it was open at idle, the engine would not get the right fuel air mix, and could stumble or quit, requiring restart.


perhaps it would be wise for us to pay attention to.....and periodically verify flow through the PCV system.Absolute, and is why most facilities will see it as a quick buck in any oil change service procedure.


if one were to have their valve covers offIt's best to use contact/brake cleaners that are quick to dissolve oil, but also very quick drying agent.
Used with compressed air is the only verified way to know crud is not hiding in hidden panels of baffle.

I have no idea yet what Berryman's B-12 Chemtool is.
Regardless, if it lays there if spilt, and never dries, then it's not the right chemical in the end.
Pre-cleaning, sure.

Good LUck

And a Warning to all Pilots of single / twin engine aircraft.
If you just purchased one, immediately remove the oil pan and clean out the inch thick sludge.
These guys are the worst as owners who always change the oil cold.
But don't expect FBO's changing it hot either.

This is required to all engines.
Just change it hot the minute the key is turned off, and most of the problems never happen.
Add fresh oil during the end of drain to push out remaining old oil.

http://www.berrymanproducts.com/ and will look into it, Thanks'

I did not post pictures or links to the pictures that I saw because they are not my pictures....and they are in other forums.
As a moderator......it is not in good form to link to other forums that are "in competition" with this one........against forum rules.
If you do a google search on 1mzfe and then select images.......you will find some very easily.

I have used brake cleaner and Berryman's.....I like the brake cleaner because it dries fast....but have found that the Berrymans B12 Chemtool cuts through crud a LOT better than brake cleaner.
Again....as you will be draining it out.....and any crud that you clean.......while the valve cover is OFF the motor.....no worry about the crud getting on down into the motor.

The vaccum applied from the intake to the PCV valve is maximum at idle.....Most PCV valves have a spring inside......and higher vaccum will push the plunger against the spring.....making for a smaller opening......restricting flow.
Less vaccum (minimum at Wide Open Throttle) will have less pressure against the spring.....so you will have a bigger opening.
So.......this will give you a smaller opening for higher vaccum and a larger opening at less vaccum.
Of course.....if the opening were the same......more air will flow through the same opening with greater vaccum.....so the spring evens out the total flow under varying vaccum conditions.
I am sure that there is a better way to explain that what I have done.....
Point being.....a PCV valve is not just a check valve to prevent back pressure from going into the crankcase.....but is also a precise metering device.

On several vehicles that I have owned.....I have seen a variety of PCV valves listed in the aftermarket......some that CLEARLY are not comparable to OEM.
This can lead to too much or too little flow......either one can cause problems.

Short trip driving is super hard on a motor.....however a restricted or completely blocked PCV system is bad under all driving conditions.

As for cooler thermostats........I plan to change my thermostat as soon as the wisconsin weather improves (Feb is not a good time to work on cars unless one has a heated garage).
The thermostat has never been changed on my 2003 Sienna.......and it calls for a 180 degree thermostat........that should not start to open until at LEAST 176 degrees....as per my Toyota factory repair manual.
My father commented that just before he sold the vehicle to me....he noticed that the heat was not as hot as he was used to.......
I connected my ScanGauge to the OBDII port.....and the motor stays between 163 and 168 degrees......
Putting the 2 bits of data together, I think that the thermostat is opening too early.
I asked my father if there was a possibility that the thermostat had been changed (it has not) because I see that there is a "alternate temperature" thermostat listed that is 170 degrees (in the aftermarket).
I plan to replace my factory original thermostat with the OEM 180 degree one.......from Toyota.

I wonder if the cooler running thermostat (180 degree OEM opening early) is common.....which would also, possibly, contribute to the sludge issue.

Anyhow.....I thought that I would toss the PCV idea out......as it seems to make sense....and not too much trouble to verify.
When I see pictures of the sludged motors......I find it very easy to understand how the PCV system would be clogged.

Good explanation of PVC.
Maybe not the most valid test, I used to just place a finger over the PCV valve when out of cover with hose attached & veh running to feel it slam shut.

I too used to have poor heating on the Isuzu Amigo in avitar because they rate their thermostat quite low about 170.

So I made a winter front of nice black boat seat vinyl.
This really worked nice, and also kept the ramming of road salt & sand into new radiator and into engine bay.

Simple plastic wire ties holds it in place.
If needed to, one can fold the cover down a little if gauge indicates

The finger of the PCV valve is a great test......I found that the hose for my '96 windstar was starting to collapse.....getting soft.
So....great test to make sure that you are getting vaccum and flow up through the valve.
In my case, I was able to see a problem starting to develop, and replace the hose before it became a problem.......which is what we accomplish by looking around under the hood and doing preventative maintenance.
As in the case of my catching on to the cooler operation of the thermostat.
I am a stickler for sticking with OEM specifications, unless I can see a clear advantage to changing for some specific reason.....which would be a very rare situation.

The only thing that the finger test does not do is verify if the ability to breath through the baffel area is OK.
You can probably picture how the presence of some junk on the top side of the baffel.....will tend to trap more junk as oil flows over and around it.
So the problem will snowball as time goes by.

A picture of the inside of the rear valve cover for my 2003 Sienna......after being cleaned with Simple green.

http://i993.photobucket.com/albums/af52/wiswind/2003%20Sienna/Sienna063.jpg

I wanted to add my experience with my 1998 Sienna, purchased new and now with 158,000 miles.

I first noticed I had the sludge problem at about 50,000 miles when I noticed gelled oil (consistency of jello) just inside the area where new oil is added. There were no other indications, and I never saw any performance issues or "blue smoke", etc.

I had made regular oil changes with Pennzoil regular oil, but when I took it to the dealer, they and Toyota insisted there was something I was doing wrong. In any event, I paid $2000 for them to pull off the valve covers and the oil pan, which revealed no damage to the engine, and they also performed a flush of the engine. During the flush operation, they must have spilled something on my inside back floormats, because there were areas that looked like "trails" of liquid where the fiber appear to be chemically melted -- but the dealer denied this and refuse to take responsibility, even though I knew the mats were perfect when I took the vehicle in -- yet another bad experience to add to all the other bad experiences I have had with dealer arrogance and irresponsibility (but that is another story).

About a year after the above work, I received notice of coverage for this type of event, and sent in documentation of my oil changes, I received a check for $2000 from Toyota. I was told to continue using non-synthetic oil, and to be sure to change the oil every 3000 miles.

At about 75,000 miles my oil pressure light came on, flickering at first, and then on permanently, and I took it back to the dealer. They pulled the valve covers and oil pan again. The area under the valve cover looked perfect with no problems. However, the oil pan contained many little pieces of what appeared to be carbon deposits, and the oil pickup tube screen was covered with these same deposits. They appear as tiny little hard black pieces that will break if you press on them with your fingernail, and the size of a typical piece is a little smaller than diameter of a pencil lead, and there are hundreds of individual pieces.

The dealer cleaned out the oil pan, and flushed the pickup tube, and all was good. However, since then, like clockwork, every 30,000 miles or so (about 2 years or a bit longer) the problem returns. The second time, the oil pressure light came back on. Each time I did the work myself, pulling the oil pan and cleaning out the deposits from the pan bottom and the oil pickup tube screen. After the second time, I just began doing it every 2 years or so, and everything has been fine. The bottom line is that there is no permanent solution that Toyota recommends for this problem, it is simply inherent with this engine in some instances (obviously not all).

So mainly I just wanted to add my experience, and state that in many cases with the oil pressure light active, I suspect the problem is exactly what I have, and that all the other things a dealer may want to do will be fruitless and needlessly costly. Pulling the oil pan is a relatively simple and cheap operation (it takes me about 2 hours start to finish, and I don't have a lift) and it is simple to see whether the pickup tube screen is covered with deposits.

At 158,000 miles, my Sienna still has good acceleration, does not burn oil, and gets good MPG.

By the way, I live in Texas, with hot summers and mild winters, so any theory that says that the problem relates to cold weather is incorrect IMHO. Last, but not least, anyone who thinks this problem is due to not changing the oil frequently enough is just plain wrong -- I don't know what to say to them other than just search the web for people's experiences, many of them very careful to change their oil every 3,000 miles as I do, and the problem still occurs, and further Toyota has acknowledged the problem -- what more can you possibly want to accept something as the truth regardless of your personal experience?

I hope this helps anyone having this problem, since I assume that many affected Toyota vehicles will continue to live on for some years to come, many with new owners when the vehicles are sold.

We have been fighting with Toyota as one of our Toyota Sienna mobility vans has the sludge problem. It is still under warranty but Toyota will not do the repairs because the owner stated that he did not change the oil on the van. We a company that sells wheelchair accessible vans so this van is very critical to our customers needs but Toyota will not step up.

Have any of you performed your own engine flush on your engines? I have flushed many of my cars myself and have suffered no ill effects. I plan of buying a sienna soon and will do the same flush on it. Only cost 4-5 bucks and takes 2 minutes before and oil change. Seems like it might save a lot of trouble for everyone. Has anyone ever suffered a breakdown due to a flush? I know it can clog the pick-up screen if not done in idle or if there is too much sludge to begin with.

If there is a lot of sludge, it can cause problems.....clogged oil passages and clogged oil pump pick-up screen.
I have used AutoRX, which is more gentle......and does work.
I would not assume that your Sienna has a sludge issue.

Take note that the baffel that you see when you remove the oil fill cap has a rough black coating that was put on at the factory......THIS is NOT sludge.

I have a 2003 and have pictures of what it looked like under the valve covers.......not any issue in my case.
My suggestion, if you buy a older Sienna would be to replace the valve cover gasket (at least the front one, which is much easier to do than the rear one).
This will give you the chance to see how clean things are up top.
If you replace the spark plugs......then the spark plugs and valve cover gaskets are a nice pair of jobs to do together.

VERY CRITICAL is to make sure that the PCV valve, located in the rear valve cover, is not clogged.
If that should become clogged, then it will cause sludge issues.

Any info is good please; Doing research, Sienna, Rav 4 and Lexus RX 350 09, same motor.
All motors prone to gell. I purchared an 09 with 32k used with no records.
Burned 2 quarts in 500 miles. Smoked all times.
Did engine wash and put in Seafoam.
Doing much better now.
Changed oil 4 times.
Only smokes at start up.
Lexus wont touch it.
Is there any way to get Lexus to help on this?
Any ideas or help is great....

Proman,

If you're still around. I know it's been a while, but you'd asked if I would give you an update on the 2009 Sienna we bought. So... For oil, so far, so good. I have not noticed any engine problems at this point and we're at almost 60K miles. Yes, the oil changes have to be made at that particular dealership.

Here's what I've found about this whold deal though. The oil changes are free, but I think it's their trick to get people in as most customers will agree to the other items that they throw on the list to do. I fell for one of the items once and then decided to do some research. Everything was good the first couple of times I took it in - no charges, etc. They even washed the car for me and all. But then they started trying to add things that were not necessary - even items that were not on the regular schedule of things to do. One thing they charged me for once was changing the cabin filter. They charged like over $90.00 for that. I didn't even know what a cabin filter was at the time. After that first charge, I got on the net and checked it out. Found that I could buy the part myself and install it behind the glove box in like 1 minute. They had charged a full hour.

Anyway, the report is that the oil changes are all good, but you should only ask for the oil change and that's it. Man, what a racket delearships have going.

I'd like to hear if there are any other stories going on with this though.

Holy Buckets Waltrip,

I just read your post. Man, it sounds like you could have saved a lot of people some trouble with your solution. I wonder if my old 2003 would still be running had I had your advice back then.

Thanks for the post!