What specifically makes the 2005-2008 models unsuitable for E10 fuel?

[catnap]

I've heard the 2009 and onwards 250s can use E10 without issue and I saw someone saying that it's the fuel rail and fuel pump that are made out of a different aluminium alloy that can work with E10.

Does anyone know for sure what changed?

[royoftherovers]

8 minutes ago, catnap said:

I've heard the 2009 and onwards 250s can use E10 without issue and I saw someone saying that it's the fuel rail and fuel pump that are made out of a different aluminium alloy that can work with E10.

Does anyone know for sure what changed?

https://www.footmanjames.co.uk/blog/e10-petrol-threat-for-classic-cars#:~:text=The prolonged use of E10,%2C if E10 is introduced.”

[catnap]

25 minutes ago, royoftherovers said:

https://www.footmanjames.co.uk/blog/e10-petrol-threat-for-classic-cars#:~:text=The prolonged use of E10,%2C if E10 is introduced.”

Thanks but that doesn't really answer the question.

I'm looking to see if it's worth getting the bits that have changed between 2006-2008 and 2009+ models from a wrecked car and swap them in to make mine compatible with E10. That page doesn't tell me anything other than "use super unleaded if you need E5" which I already know.

[Linas.P]

That is very good questions and it seems there is no answer to it. According to Lexus actually cars from October 2007 are already fine with E10.

https://mag.lexus.co.uk/e10-petrol/

But as you said - it is not clear what parts are in particular were changed. I tried to look trough part numbers related to fuel delivery and although some parts have revisions it is not clear that it was anything related to E10. Now again I have extensively used E10 and even E85 on 2006 IS250 without issues, note as well that in most of Europe use E85 and at very least E10 as default fuel, so most European IS250 were running 10-85% ethanol since the beginning and I have not heard any particular issues. 

[catnap]

49 minutes ago, Linas.P said:

That is very good questions and it seems there is no answer to it. According to Lexus actually cars from October 2007 are already fine with E10.

https://mag.lexus.co.uk/e10-petrol/

But as you said - it is not clear what parts are in particular were changed. I tried to look trough part numbers related to fuel delivery and although some parts have revisions it is not clear that it was anything related to E10. Now again I have extensively used E10 and even E85 on 2006 IS250 without issues, note as well that in most of Europe use E85 and at very least E10 as default fuel, so most European IS250 were running 10-85% ethanol since the beginning and I have not heard any particular issues. 

Sadly mine's an early 2007 car so is marked as non-compliant. The price of E5 at the pump is rather eye-watering at the moment.

Good suggestion on part numbers though. I've been going through the parts diagrams and I can see some items of the fuel system changing in 2006 and 2005, but nothing specifically for 2007 cars. Also, none of the parts seem to be for actual fuel delivery (pump, hoses, seals, fuel rail, etc)- it's only things like brackets and the fuel rail crossover assembly that changed.

Good to know that you've run E10 without any problems though. Was it for any length of time, or just temporarily?

[Linas.P]

10 minutes ago, catnap said:

Sadly mine's an early 2007 car so is marked as non-compliant. The price of E5 at the pump is rather eye-watering at the moment.

Good suggestion on part numbers though. I've been going through the parts diagrams and I can see some items of the fuel system changing in 2006 and 2005, but nothing specifically for 2007 cars. Also, none of the parts seem to be for actual fuel delivery (pump, hoses, seals, fuel rail, etc)- it's only things like brackets and the fuel rail crossover assembly that changed.

Good to know that you've run E10 without any problems though. Was it for any length of time, or just temporarily?

I would say I covered good ~20k miles on it specifically in 2006 car, like 2k on E10 and ~20k on E85. And I have done more miles in IS250 on E85, but those were abroad and they were 2010 and 2012 models anyway. I mean if E85 hasn't done it, then I can't believe E10 would be an issue. One thing to note, do it at your own risk - that it worked for me does not mean it is good idea. To be fair I done it because I just didn't know I am not suppose to do it in 2006 (and because I was used to do that in my previous IS250's) and only realised that when whole craze of switching to E10 started in UK, I thought IS250 was modern enough car to be what is known as "flex-fuel" ready (which it kind of is because of "smart ECU"). Some cars are specifically marked as flex-fuel, especially in US, but most modern cars are flex-fuel even if they don't say so. Overall, what makes car flex-fuel is that ECU should be able to tell what fuel car is running on and adjust accordingly (which IS250 does), the second part is that materials used on fuel system should be resistant to ethanol... again I assumed all IS250 are fine, but turns out something between 2005-2007 isn't suitable. But it is kind of bizarre, because other models from same years and even older Lexus cars are fine.

I did have some idea that ethanol isn't really great, but I didn't know the 2006 car specifically shouldn't be running it. My idea was based just on general knowledge that ethanol is hydroscopic and if left in tank for long time it could accumulate excess water leading to corrosion, or simply poor running of the car. So the only "prevention" I did (if you can call it that) I tried to never leave E85 in tank for long periods of time, so I would fill full tank only when I was relatively confident I will use most of right away. Again never had any issues with car and it was still running fine at 200k miles.

[catnap]

45 minutes ago, Linas.P said:

I would say I covered good ~20k miles on it specifically in 2006 car, like 2k on E10 and ~20k on E85. And I have done more miles in IS250 on E85, but those were abroad and they were 2010 and 2012 models anyway. I mean if E85 hasn't done it, then I can't believe E10 would be an issue. One thing to note, do it at your own risk - that it worked for me does not mean it is good idea. To be fair I done it because I just didn't know I am not suppose to do it in 2006 (and because I was used to do that in my previous IS250's) and only realised that when whole craze of switching to E10 started in UK, I thought IS250 was modern enough car to be what is known as "flex-fuel" ready (which it kind of is because of "smart ECU"). Some cars are specifically marked as flex-fuel, especially in US, but most modern cars are flex-fuel even if they don't say so. Overall, what makes car flex-fuel is that ECU should be able to tell what fuel car is running on and adjust accordingly (which IS250 does), the second part is that materials used on fuel system should be resistant to ethanol... again I assumed all IS250 are fine, but turns out something between 2005-2007 isn't suitable. But it is kind of bizarre, because other models from same years and even older Lexus cars are fine.

I did have some idea that ethanol isn't really great, but I didn't know the 2006 car specifically shouldn't be running it. My idea was based just on general knowledge that ethanol is hydroscopic and if left in tank for long time it could accumulate excess water leading to corrosion, or simply poor running of the car. So the only "prevention" I did (if you can call it that) I tried to never leave E85 in tank for long periods of time, so I would fill full tank only when I was relatively confident I will use most of right away. Again never had any issues with car and it was still running fine at 200k miles.

That's very useful to know, thank you. Was yours a UK car as well?
Yes, it's annoying that some of the older cars were fine with E10 too. My 300 Sportcross (sitting on the drive while I rebuilt the cylinder head) is compatible and that's from 2002. Your suggestion about filling up and using E10 when you know it won't sit in the tank is a good once and I might use that for the longer trips where I'm going to burn most of it immediately.

I might contact Lexus directly and ask them specifically why this is the case, as it might be something small or maybe even an error on their part. They might know internally that it's fine but can't guarantee it.

The only thing I have noticed is that my tank MPG is up to 35 with super unleaded from Esso (£1.82/litre at the time...), and it was around 30-31 with E0 "standard" petrol from a local garage. They're discontinuing it shortly as it's not profitable for them to sell unfortunately.

 

[McShmoopy]

This would be very useful to know actually, I've made a few recommendations to people to get 2008+ IS's due to the fact it can work with E10 without issue but it does seem odd how its not clear why it isnt compatible. Lets hope its an error on Lexus's part. 

[Linas.P]

4 hours ago, catnap said:

That's very useful to know, thank you. Was yours a UK car as well?

It was UK car. I doubt it is Lexus "mistake", but maybe they have some "agenda". For example years coincides with fuel pressure sensor recall affected IS250s, who know maybe Lexus just being overly careful just in case. You know how corporations are - better safe than sorry, maybe there is nothing wrong with these cars, but just because they had something related to fuel system, they just wont risk it and makes blanket policy that they can't use E10. 

[Vintagesixtysix]

I thought the main issue that manufactures of older petrol engines ( including motorbikes etc) was around rubber and plastic parts.

Higher ethanol can cause drying ( brittleness) and deformity.

Ive actually seen in the flesh a motorbike petrol tank that has been deformed by higher ethanol.

it’s a bit like when you pick the wrong type of plastic pot out of the recycling to wash your paint brush in a solvent and it causes the pot to start shrivelling and deforming.

So replacing all those parts on the fuel delivery system with later model seems like a logical solution…. But as far as I can see it’s impossible to tell which.

Plus it would be no mean undertaking….. depending obviously on your skill set.

[Spock66]

7 minutes ago, Vintagesixtysix said:

So replacing all those parts on the fuel delivery system with later model seems like a logical solution…. But as far as I can see it’s impossible to tell which.

But if E10 is bad for some vehicles E5 must by definition be half as bad, so I don't think it's a black and white answer, most likely just based on assumptions and probability as to which vehicles may be impacted and which ones won't.

[Linas.P]

11 hours ago, Vintagesixtysix said:

I thought the main issue that manufactures of older petrol engines ( including motorbikes etc) was around rubber and plastic parts.

Higher ethanol can cause drying ( brittleness) and deformity.

Ive actually seen in the flesh a motorbike petrol tank that has been deformed by higher ethanol.

it’s a bit like when you pick the wrong type of plastic pot out of the recycling to wash your paint brush in a solvent and it causes the pot to start shrivelling and deforming.

So replacing all those parts on the fuel delivery system with later model seems like a logical solution…. But as far as I can see it’s impossible to tell which.

Plus it would be no mean undertaking….. depending obviously on your skill set.

I really doubt it is the case with these 3 specific models and only between years 2005-2007. Meaning that Lexus already used "modern" plastics and rubbers in 1989 with launch of LS400 and continue to do so for 16 years, but then just for 2 years and for 3 engines switched to old rubbers.

Overall I think you right - there is some part which Lexus believes could be damaged by ethanol or potentially not as resistant, but they do not say what it is. But it isn't all seals in fuel system.

As well the point Andrew makes is important - we already drive on 5% ethanol, if the parts would really be that susceptible we would already have issues. At least that is if theory about materials is correct, because if you run E5 in classic car which can't take ethanol, that would already be enough to melt everything there. So the question is valid - why E5 works, but E10 doesn't?

[catnap]

15 hours ago, Linas.P said:

It was UK car. I doubt it is Lexus "mistake", but maybe they have some "agenda". For example years coincides with fuel pressure sensor recall affected IS250s, who know maybe Lexus just being overly careful just in case. You know how corporations are - better safe than sorry, maybe there is nothing wrong with these cars, but just because they had something related to fuel system, they just wont risk it and makes blanket policy that they can't use E10. 

I left a comment on the official Lexus E10 article asking about this, which I can see this morning was removed- no idea why. A lot of people had been commenting and asking about using E10 so I was hopeful they would let me have some info.

So I've now sent off an email to the general contact page of the UK website and I'll see if that comes to anything. I do agree that they are likely being as conservative as their lawyers are telling them to be, but if there's a tiny chance of something corroding over 10 years then well, this car won't last that long anyway.

I really can't believe it's fine with E5 but not E10- there has to be a reason behind it.

If I hear anything I'll post back here.

[catnap]

Just spoke to the local dealer- "There is no change you can make to that car to make it compatible with E10".

I'll go elsewhere for my info as that's nonsense. Plus he checked with his service advisor suspiciously quickly- barely enough time to get the sentence out so I think I'm being given the runaround.

[Linas.P]

19 minutes ago, catnap said:

Just spoke to the local dealer- "There is no change you can make to that car to make it compatible with E10".

I'll go elsewhere for my info as that's nonsense. Plus he checked with his service advisor suspiciously quickly- barely enough time to get the sentence out so I think I'm being given the runaround.

Sorry, forgotten to say - you are not the first one Phil. I am sure there were at least few people who contacted Lexus UK and got no answer. 

Again that is why my assumption, maybe there is nothing wrong with the cars which could be justifiably identified and replaced, it may be just some sort of corporate liability thing which they won't share publicly. Perhaps that would expose some tiny sub-par quality part and trigger another recall and they just thought - it is easier to say don't use E10, than admit we need to recall 100k cars for one o-ring which was sourced from certain supplier between 2005-2007 and turns out not to be up-to spec. 

[catnap]

12 minutes ago, Linas.P said:

Sorry, forgotten to say - you are not the first one Phil. I am sure there were at least few people who contacted Lexus UK and got no answer. 

Again that is why my assumption, maybe there is nothing wrong with the cars which could be justifiably identified and replaced, it may be just some sort of corporate liability thing which they won't share publicly. Perhaps that would expose some tiny sub-par quality part and trigger another recall and they just thought - it is easier to say don't use E10, than admit we need to recall 100k cars for one o-ring which was sourced from certain supplier between 2005-2007 and turns out not to be up-to spec. 

Very true!

I've got a friend who knows someone who works in the Crawley dealership so I'm buttering him up to ask if they can find out.

[Texas]

Other alternative is to just go with E10 and see what fails and then replace that with newer ( E10 compatible) spare part, what’s the worst that can happen? Anyone stepping forward to take one for the team?

But seriously though if something in the fuel supply line fails ( leaks is prob the most obvious) then as worst I can see it fouling injector, what are you thoughts?

[Texas]

15 minutes ago, catnap said:

Very true!

I've got a friend who knows someone who works in the Crawley dealership so I'm buttering him up to ask if they can find out.

I can’t see any actual dealership knowing the facts of why 06-07 is not compatable!

At least it would be known at Lexus UK HQ but then perhaps not!

[Linas.P]

3 minutes ago, Texas said:

Other alternative is to just go with E10 and see what fails and then replace that with newer ( E10 compatible) spare part, what’s the worst that can happen? Anyone stepping forward to take one for the team?

But seriously though if something in the fuel supply line fails ( leaks is prob the most obvious) then as worst I can see it fouling injector, what are you thoughts?

Mate... I literally drove for 20k miles on 85% ethanol and nothing happened... so what are the odds of something going wrong on 10% ethanol? Well I guess "nothing" is not completely accurate, as I haven't inspected every single part under microscope before and after I did it (i.e. it is not scientific), but nothing failed to point where I would have had fuel leaks, or faulty fuel pump, or clogged up-lines or injectors. 

[catnap]

3 minutes ago, Texas said:

I can’t see any actual dealership knowing the facts of why 06-07 is not compatable!

At least it would be known at Lexus UK HQ but then perhaps not!

Perhaps not but it's worth a shot. Especially if his friend is a service tech who can do some digging- or can find out which specific parts changed in that time period. Now I can't see much changing on Amayama.com but there may be more info available to dealerships that's not online.

[catnap]

I think I've only gone and found the part!

I realised the EFI System diagram doesn't show in the in-tank fuel pump so I went hunting. And look what changed in October 2007...

[Linas.P]

Other tricky thing - they may have switched supplier for certain part, or the supplier changed sub-contractor without changing part number. Say for example fuel pump is Denso, but maybe Denso was buying o-rings from Chinesium Rubber Corp between 2005-2007, but later switched to Cheap Rubber Products Inc. From Lexus perspective Denso still supplies them with fuel pump, but from Denso perspective maybe they know something like certain o-ring when used with ethanol could reduce it's reliability from estimated 100k hours, to 85k hours... and Lexus spec. requirement was for that part to be no lower than 90k hours... so that part is technically out of spec. and therefore using E10 is not recommended. 

Obviously, we don't know what the standards were and what tolerances were allowed, and sadly Lexus doesn't seem to want to share. 

[Linas.P]

5 minutes ago, catnap said:

I think I've only gone and found the part!

I realised the EFI System diagram doesn't show in the in-tank fuel pump so I went hunting. And look what changed in October 2007...

You may be on the money here. 

[catnap]

Further digging. The entire fuel pump assembly is listed as 77020A, which changed in 10/2007.

Going through the individual parts in the assembly, the only two things which appear to have changed are the plastic "sub tank" (which I believe is the outer skin of the pump assembly as it comes out of the tank) and a gasket:

 

It looks like these two parts are the only thing that changed in the entire system.

[catnap]

2 minutes ago, Linas.P said:

Other tricky thing - they may have switched supplier for certain part, or the supplier changed sub-contractor without changing part number. Say for example fuel pump is Denso, but maybe Denso was buying o-rings from Chinesium Rubber Corp between 2005-2007, but later switched to Cheap Rubber Products Inc. From Lexus perspective Denso still supplies them with fuel pump, but from Denso perspective maybe they know something like certain o-ring when used with ethanol could reduce it's reliability from estimated 100k hours, to 85k hours... and Lexus spec. requirement was for that part to be no lower than 90k hours... so that part is technically out of spec. and therefore using E10 is not recommended. 

Obviously, we don't know what the standards were and what tolerances were allowed, and sadly Lexus doesn't seem to want to share. 

Yes this is entirely possible. But when a part changes in any way it usually appears as a "Sub" of the original part, or as a slightly different part number from a certain date- neither of which are happening here. That's not to say that it hasn't happened without being detailed, but I'm somewhat hopeful at this point.