Will 2-stroke oil damage Urea catalyst?

The fuel is Ultra-low sulfur to prevent poisoning, but 2-stroke oil would be high sulfur (I’m guessing).

Why do you need to use 2-stroke oil?

Once again people just can't resist dumping stuff into their fuel tank. If you feel the need for an additive why not just use one intended for the purpose. Or just fill up with some B5 or less biodiesel. You don't even have urea on your car, are you planning on a newer model?

I wasn’t talking about myself or my car. I was just curious if “those people” who do use 2-stroke oil are damaging their DEF catalyst

I’m an engineer who is curious about how things work. (Guess lightflyer’s not an engineer or curious.)

Not curious at all as there is absolutely no need to do this and I doubt there are many if any of "those people" you speak of. Not to mention voiding the long warranty for dumping unapproved stuff in your fuel.

Why would you do this?

Also, the SCR catalyst would not be what is first impacted by putting something in the fuel that doesn't belong, the DPF would.

Some modern name-brand 2-stroke oils, the higher quality ones that carry the JASO or ISO GD or GC certifications are low ash, synthetic or semi-synthetic. The lower grade stuff is often still low ash, with API certification, but would carry a lower ISO or JASO rating, if it even would carry it at all (many do not).

Still, NONE of the several 2-stroke oils should ever be put in your diesel's fuel tank.

I just read a post today

where a common rail TDI owner said he puts 2-stroke oil in every tank of fuel. It does seem pretty dumb, but I didn’t see anybody correct that guy’s mistake

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Actually back in the ALH or earlier days there were quite a few TDI members who would add 2stroke oil to the Diesel, but that was then!

Yes but different fuel and different cars with much more complicated emissions systems nowadays.

BeetlePD said:

but I didn’t see anybody correct that guy’s mistake

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A good majority of the users of 2 stroke oil are bald or all grey. Their daddy did it and so do they. It is almost like a cult to most, if you try and tell them they are being stupid they just call us whippersnappers and to get off their lawn.

Please see post #26 here:
http://forums.tdiclub.com/showthread.php?t=358699&page=2

I know we are talking about apples to oranges as the OP was asking about using it in a DPF / SCR equiped vehicle and the post attached shows it being used in a much older vehicle with much less emissions equipment. However, I was impressed with the picture shown and how clean the pistons and cylinder bores are.

^^^But...you have no idea WHY the pistons and cylinder bores are clean. The 2-stroke oil might have nothing to do with it...

tdiatlast said:

^^^But...you have no idea WHY the pistons and cylinder bores are clean.

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Probably a snapchat filter, lord knows it makes ugly women look like supermodels.

Some of us prefer to never have to remove the head in the first place.

Sprocket said:

Please see post #26 here:
http://forums.tdiclub.com/showthread.php?t=358699&page=2

I know we are talking about apples to oranges as the OP was asking about using it in a DPF / SCR equiped vehicle and the post attached shows it being used in a much older vehicle with much less emissions equipment. However, I was impressed with the picture shown and how clean the pistons and cylinder bores are.

Click to expand...

Good points related to pre-CR (common rail) TDIs. One thing that caught my attention from the thread above is the reference to 'increases the level of aromatics'. Then while reading the Chevron paper entitled 'Diesel Fuels Technical Review' I came across this statement:

"Aromatics
Most studies indicate that reducing total aromatics has no effect on the emissions of HCand PM. However, reducing total aromatics from 30 percent to 10 percent reduces NOxemissions. Studies done on the influence of polynuclear aromatic hydrocarbons show thatreducing the di- and tri-aromatics reduces emissions of HC, PM, and NOx.17"

So potentially there might be a relationship between adding two stroke oil to D2 in pre-CR TDIs and cleaner combustion.

For TDIs with DPF research further or better yet do not use.