CypressIS

Well my experience isn't going so well. After getting the CEL/MIL and taking it back to the dealer, they tell me the technician found 'no codes' and everything is fine with the car. I'm very unhappy about all of this and have contacted Lexus corporate. We'll see where this next step leads to.

hades281

Guys, I finally had an opportunity to see this TSB. For the sake of everyone who might be facing this problem, I wanted to provide a recap of what it says.

Symptoms:
MIL On -- Trouble codes P0300, P0301, P0302, P0303, P0304, P0305 or P0306
OR Runs rough after coming to a stop at operating temperature
OR Misfires after cold soak startup.

2006-2010 cars affected (VIN ranges in an earlier post).

Procedure is to replace pistons, rings, and valve stem seals ONLY, unless the car being serviced is an '06 that has not had the springs, lash adjusters and retainers replaced in an earlier recall - in which case, those parts are also replaced.

Parts:
- All engines, 2006 to current, have the same PISTON part numbers, and the part number has NOT changed. In this case, you are getting fresh parts but they are of original design.
- All engines, 2006 to current, were built with PISTON RING set P/N 13011-31120. Piston rings will be replaced with NEW P/N 13011-31221.
- Valve stem seals are called for replacement, but there is no P/N in the TSIB calling them out. Instead, a "Gasket Kit, Engine Overhaul" kit is called out. The part number for this kit has not been changed by the TSIB -- so, if the valve stem seals are included in that kit, they are of original design.

There is a note to clean/decarbonize the cylinder head and valves.

Your engine block:
The block will not be honed. If there are no vertical scratches and the crosshatching is visible in the bore, the block is reused - else, the short block assembly is replaced.

Technical analysis:
Do the technical minds here agree that because the ONLY part redesign is the piston ring, it means that Lexus is attempting to limit blow-by by fitting tighter rings in the engine?
- Is this because the reduction of blow-by will reduce the volume of crankcase vapors generated?
- Is this because the factory rings have a loose fit by design error? I wondered if possibly some rings are wearing down, improperly machined, or have bad metallurgy, but UOAs do not seem to indicate an engine wear problem.
- If it is effective at all, wont this just slow the problem rather than eliminate it?
- What could happen to the compression ratio and engine wear as a result?
- Could carbon buildup at / between the RINGS be the real problem here? There was a photo in the TSB of an intake valve, and though there was some crud it just didn't look bad enough to cause the problems we are talking about. I don't know how the rings are different.

I hope I never need to have this service performed. I have a bad feeling that the engine won't be quite the same after the repair...

Comments?

VIS250P

iTrader: (1)

LEt me get this straight.. Im a Lexus Tech for 4 years and present... Today I was talking to my buddy next my bay and told him "U work on Piston from IS again"..

Im curious, what gas ya use? I use 92 or 93 gas octane because this motor recommend high gas.. One of my team leader told me that reason why other people bring their IS because the car run rough and idle crazy... We found out it is a Carbon build up because they use cheap gas.. I believe it is true they use cheap gas because I see the valve cover full black...

Oh I worked on 9la on my car.. I took the fuel rail off and saw the injection clean and no black cover at all because I use 92-93 Octane.. I worked on customer car and doing 9la again.. I saw full black on the injectors..

chikoo

I drove a 2011 loaner with 10k on it and it revved tighter and not as free as my 2008 IS.
My 2 cents.

Kurtz

iTrader: (1)

It has not fuel, it's a design flaw common to a lot of direct injection gasoline engines (ie many other than Lexus have had the issue).

If you're a lexus tech you'd be aware that the part that causes the problem isn't even touched by fuel.

that's why the 250 has the problem and the 350 does not.

Fuel hits the valves on the 350, keeping them clean. It doesn't on the 250.

I agree with the analysis that the ring "fix" isn't likely to be a fix, just something to make it happen less often (possibly a lot less often though- and I don't think needing a couple-hundred buck top engine clean every, say, 100k miles, is too onerous if this fix gets it to that point).... but higher octane fuel sure ain't a "fix" either and dozens of folks running premium have reported having issues in the long carbon buildup thread (which means hundreds, if not thousands, of others have too who aren't posting about it)

mickificki

i'm not sure where you get 93 octane but here in so cal i dont see many stations doing 93 octane, only 91.

and i think lexus recommends 91 octane no? if it was really important that we use 93 they'd state it.

but i think you'd know that, since you're a "lexus tech"

mickificki

i drove one too, same year, and i thought it drove much better. and the stock hid's are awesome.

heyarms

iTrader: (5)

First off, Texas (southern states) have higher octane gas. Has to do with elevation I believe, but after driving to Cali in october I noticed yalls gas has less octane and my car felt like a slouch out there in high elevation (normal).

Secondly, VIS250P is a Lexus tech, why's everyone suddenly not believe him. My dealer (although everyone, including myself, don't believe 99% of what they say) told me carbon build up is mostly due to people using regular grade gasoline.

This does lead me to bring up,my dealer (westaide Lexus) told me IS250's "do not have a carbon build up problem" and there is "nothing that says they do". I told him it's well documented and a fact but he didn't believe me...

White350

Changing pistons, and rings on this TSB is nothing more than a Bandaid, and they know that once its done, they won't see you for another 80,000k when you are far out of warranty. to really stop the carbon from messing up the valves, they would need to design a better flowing head that prevents air from coming back up the intake valves (supercharger would work well lol)

and as far as carbon build up on the pistons, its a result of using 91 Octane It burns slower.

when I bought my 07 i was getting the codes mentioned in this thread and actually took a scope and looked in the cylinders and saw the carbon build up, since then ive been using 89 octane and drive my car somewhat hard (track days i run 94) ive recently scoped it and its has visibly less Carbon and hasn't thrown any codes or run rough in the last 5 months,

I'm going to run a couple of cans of seafoam through the motor to see if i can get the cylinder heads cleaned up some.

This is what I've done for my car, I wouldn't recommend it to everyone unless you know what knock sounds like or don't know how to read plugs, but my car hasn't knocked once or thrown a misfire code since i've started using 89.

I'm a Mazda tech and I've built 3 rx7's that ive beat at the track and a few hondas

autox250

Heyarms.... You should believe us techs... Unfortunately VIS250P has no idea what the hell hes talking about. Gas grade has no effect on the carbon buildup. I encourage VIS to access TIS and educate himself reading our bulletins and tech tips. All direct injector's tips come out with their tips black its normal and youd know that if youve done the rail recalls like we all did. Its a pcv recirculation issue, the only remedy is the bulletin for pistons that extends the life of the engine. Please VIS if you dont know ask, your team leader will help you get access. We are in a priviliged position to offer help and advice thru our experience

autox250

Btw VIS250P none of our engines sludge up like the old 3.0, 3.3.... If their valve covers are black then theyre not doing frequent oil changes, thats a fact

Kurtz

iTrader: (1)

Not really no.

Octane, in and of itself, has nothing to do with the speed at which a fuel burns in a properly operating engine.

Octane is a measure of a fuels resistance to detonation. That's all it is.

For a much more detailed explanation of the topic see here:

http://motorcycleriderz.motionsforum...t-a-fuel-burns

It goes into a decent bit of specifics about the speed of burning fuel in an engine, and why octane is not a measure of that.

CypressIS

That's exactly what Westside Lexus has told me on 2 occasions. I even showed them a copy of the Top Engine Clean L-SB and they still proceeded to act as if this all was a fabrication.

FWIW -- We have only run 92/93 octane as per the owner's manual since buying this car new. Westside Lexus told me the rough idle was probably from using lower grade gas, and then tried to sell me a fuel injection cleaning service.

MIA_LEX

iTrader: (4)

thanks..
I got my car back today and i was reading the paperwork and found out that my radiator was apparently cracked "upon inspection tech found radiator crack, radiator filler neck dry and brittle, leaking, replaced radiator, goodwill warranty." So I got away with new pistons, radiator , and some spark plugs...All I had to pay for was the plugs from sewell.. So car feels good now, noting that it never really did feel bad... Never had a misfire,CEL,it occasionally dropped RPMs and thats was mad me worry about it. Im going to go easy on it for awhile and then eventually go WOT and see wassupp Goodluck to anyone else

heyarms

iTrader: (5)

If you want to tag team that dealer, let me know and we can go up there together. PM me. I've always hated Westside Lexus, always treat me like crap but they're so close to home... :/ I refused to buy from them tho, went all the way to Austin haha