Phosphorus and Catalytic Convertor "Poisoning"

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Nov 26, 2002
Texas & BWI Area
Question, I am finalizing the install of my new Catalytic Convertor and 2 02 Sensors on my GM car. At 110,000 the cat substrate is starting to come apart and rattle. A) Could my from day 1 use of Mobil 1 etc caused a diminshed cat life? Some posts here talk about a 20% life reduction in cats due to P content in Syn oils. B) Could the previous intake manifold leak caused coolant to infiltrate and damage a cat? C) Will the continued use of Mobil 1 TSUV, EP or German Castrol diminish** the life of the new cat? Anyway just thinking about this. IMO protecting the engine supercedes secondary "support" components like the cat-con. As one poster said, what is more important the cat or your engine internals. *lol* So,I will keep using the good stuff oil regardless.
I think that thermal cycling and the types of roads you drive on would have a bigger influence. P would poison and thus deactivate the cat - thus causing O2 sensor 2 to trip the CEL. Breaking apart of the substrate is a mechanical failure. Deactivation of the cat would allow the substrate to remain cooler, improving life if doing anything... JMH
With all the fuel additives, MMT and the likes, compounded with oil-burning motor to complicate matters further, your end-result would be phosphorus poisioning, amongst other things in the additives/oil package. On the other hand: a rattling in your cat just means that the unit has suffered from severe shock some time during it' useful service life and the structural integrety has been compromised. IMHO replace it. Aftermarket cats are fairly cheap to begin with.
No, M1 had nothing to do witht he cat breaking up. Cheap cat design and materials combined with normal wear and tear. GM is well known for early cat. failure, DC models with cats made from caoted ceramic fail often and Toyota has also had a problem on some models wioth pup cats. that have the coated ceramic cats failing early! I think that it is just part of the material and design.
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