Additive Removed Due To Cat Failures?

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Rhoyd

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The following is all hearsay...

A couple of guys were talking over the weekend and the topic turned to motor oil.

One guy said he liked Amsoil and the other guy agreed. They then began to discuss other brands that might have good characteristics.

One of the guys stated that Amsoil, Valvoline VR1, and Shell Rotella have an additive/detergent that almost all other oil manufacturers have removed due to its contamination of catalytic converters on OEM equipment.

One guy recalled that he had actually heard this before from two or three friends.

So with this info can anyone elaborate on this topic?

Does anyone have any information on this mystery additive that has been removed from some formulations?
 
They are likely refering to phos. being removed from ALL passenger car oils that choose to meet the current specs.
 
I believe it amounts to reduced zddp because the phosphorus was thought to be bad for the cat. I think SH was around 1200 ppm zinc and phosphorus, SJ and SL around 1000, and the new SM is down to around 800 or less. Rotella should be around 1200 or so. Others will post with more specific data. You can buy zddp additives to boost it back up, but supposedly other additives are used to sort of replace it. Maxlife has 300 ppm moly which seems a reasonable make up for the reduced zddp.
 
Nothing removed. Amounts lowered. To meet API SL and SM. P (phoshorous) lowered via lowering ZDDP (common zinc phosphorous additive). Not a mystery at all. Read about it, hundreds of threads dedicated to the subject.

Just another "motor oil is mysterious" conversation.
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TallPaul, what do you mean by "Maxlife has 300 ppm moly which seems a reasonable make up for the reduced zddp".

Is moly a substitude for zddp?
 
It's a "policy" type thing. It's a "passive" measure to add longer life to catalytic converters. It's like "Extra Strength" Tylenol. If you took 3X the regular strength ..you've got the same thing.

That is, does it really make any difference if you use a reduced zddp additive level, if the user changes it out too often ..and volatilizes even MORE zddp?
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OTOH, whatever insult anyone is doing to their cats in the volatilization of zddp will be reduced.

That's why I call it a "policy" and "passive measure".

..btw-I've never had a cat fail ..even in advanced years..but I haven't had any fancy cats ..nor fancy engines. Some may be very well balanced ..and also very expensive to replace.
 
What additives are available that can be used to boost zddp? I know SLOB was one that's high in zddp, but I can't find the stuff anywhere. Saw alot of it on the shelves before I knew what it was. Seems to have vanished.
 
Quote:

TallPaul, what do you mean by "Maxlife has 300 ppm moly which seems a reasonable make up for the reduced zddp".

Is moly a substitude for zddp?

Click to expand...
Moly and zddp both antiwear in own ways. I think both also anti acid and thus help extend oil life. I could be off though, but I think functions are similar, but also differences that I assume enhance things so that maybe 800 zinc phos and 300 moly is perhaps better than no moly and 1200zinc phos.
dunno.gif
Bottom line: probably 6 of one, half dozen the other.


DrivewayTech: See if your Walmart has any Powerservice diesel lube oil extender left. It's in 3qt jugs in the clearance area and was about $9 last I looked. Stuff has decent zddp, like SLOB. Analysis on this site.

Als GM EOS can be bought at GM dealers and has I think 6500 or 8000 zinc and phos, go easy on this.

Fram and STP make thinner oil additives (not the blue stp thick garbage) that list zddp but nobody has checked how much.

Or just buy HDMO or Redline to get the extra zddp.
 
Quote:

What additives are available that can be used to boost zddp? I know SLOB was one that's high in zddp, but I can't find the stuff anywhere.

Click to expand...

VSOT (Valvoline Synpower Oil Treatment) has both zddp and moly (along with some other good stuff). I think you can still get VSOT if you hunt around. If not, PM me and I'll sell you a few bottles from my small stash (as I went overboard hoarding the stuff, when it looked like VSOT was going off the market).
 
Here in Michigan we don't have smog checking, and there are many cars on the road that definitely shouldn't be on the road, burning a quart a mile. Yucky.
 
The cat failures we have seen had nothing to do with being damaged by oil. Some cars just have poor cats on them and they fail regardless of the oil used in them. On the other hand,some cars have cats on them that don't give trouble for several hundred thousand miles. All converters are not built to the same quality specs and some will fail regardless of the oil used in them.
All of my cars have seen stout oils in them such as Schaeffer9000, Amsoil HDD 5W30, with no problems at all. I've seen numerous cars of varying manufacterers that were burning through massive quantities of oil yet still had no converter failures. Theres no way to convince me that a healthy engine that uses no oil is going to kill the converters if you use a stout oil like a HDEO from any maker. I think it is just the manufacterers trying to cover their bottoms due to the longer warranties on the emission systems. I like the healthy oils like Schaeffer and Amsoil produce and if I have to replace a converter on 400 thousand mile car then so be it. I know oil producers are doing a good job working around the lower zinc/phos levels but I am still fond of their CI-4 plus oils and will buy them as long as they are avalible. I have several vehicles past the 150K mile mark and they all have converters on them and none of them have needed replacement as of yet.
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