Changing oil too often....O2 sensor?

[NewGuy]

I was reading a post earlier on the board and noticed some comments about changing the oil too often negatively impacted the O2 sensor. This is the first mention of this that I have found. I would like to learn more about it. Does anyone have any thoughts on the issue? I assume that new oils gives off something that adversely impacts the O2 sensor? Do dinos do this more than syns?

Pitzer...I believe you were mentioning it earlier. Would you mind explaining? Not trying to be a pain...just want to learn something new.

 

[rpn453]

I've never heard of that either. I'd be interested to learn more.

 

[pitzel]

I have seen a SAE paper on this I believe, whereby it is postulated, with some research and empircal testing, that the exposure of the exhaust gas path instrumentation and catalyst to phosphourous found in ZDDP is dependant on, to some extent, the concentration of ZDDP in the lubricating oil. Phosphourous volatility generally decreases as the oil has been in service longer.

I will attempt to dig up the URL for the paper.

Amsoil's oils are not API-certified for the reason that they contain too much phosphorous in the form of ZDDP apparently in their formulation. Amsoil has, in the past, responded to questions of O2 and cat contamination by asserting that extended use of their non-API-certified, ZDDP-rich oils, will actually send less phosphorous into the exhaust than would using lower-ZDDP oils for more traditional drain intervals.

edit: still trying to find the paper, but This Thread has a quote from an article with respect to the formulation of the GF-4 standards.

[ February 08, 2005, 05:14 PM: Message edited by: pitzel ]

 

[Blue99]

NewGuy -

ZDDP, which has both phos & zinc components, is in suspension in the motor oil. The motor oil has to enter the combustion chamber either past the piston rings, valve guides, or thru the PCV system, etc. for the phos to enter the exhaust gas flow.

Amsoil has always contended that due to the lower volatility of it's PAO basestocks, the higher level of ZDDP in Amsoil oils, as compared to API SL or SM levels, will not be a significant source of phos contamination in a cat.

If phos levels actual decreased over the service life of an oil, the ppm's in a UOA would be significantly less than the same amounts in a VOA.

 

[kenw]

Well, I've read enough technical papers by experts over the years to know that to take them at face value without understanding ALL the base assumptions, data and testing methodologies is almost as stupid as believing everything you read on the web....many technical papers are written with an agenda to prove a pet theory and conveniently overlook other valid issues.

"If you can't dazzle 'em with brilliance, baffle 'em with bull****."

"Any highly developed magic is indistinguishable from science."

Am I calling this theory wrong? Certainy not. But I am asking you to be wary of EVERYTHING you read anywhere.

 

[haley10]

quote:

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Originally posted by Blue99:
NewGuy -

ZDDP, which has both phos & zinc components, is in suspension in the motor oil. The motor oil has to enter the combustion chamber either past the piston rings, valve guides, or thru the PCV system, etc. for the phos to enter the exhaust gas flow.

Amsoil has always contended that due to the lower volatility of it's PAO basestocks, the higher level of ZDDP in Amsoil oils, as compared to API SL or SM levels, will not be a significant source of phos contamination in a cat.

If phos levels actual decreased over the service life of an oil, the ppm's in a UOA would be significantly less than the same amounts in a VOA.

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True, but I think Pitzel was trying to say that somehow the volatility of the phosphorus also decreases with age. The ppm levels do not of course.