"I have heard that Rotella T6 should not be run in a gas engine car with a catalytic converter, is this true? Which Rotella oils are ok to run in a gas engine car with a catalytic converter? Thanks"
The reply was this:
"In reference to your query, please see below message from Shell Technical Team. Thank you. Hope this helps. For further assistance, please respond back to this email or call our Customer Service hotline and you will be assisted as soon as possible. Sincerely, Estefanie Rigor Consumer Customer Service Team Phone: 1-800-237-8645 Email: generalpublicenquiries-us@shell.com
Dear Sir, No Rotella Oils are recommended for use in gasoline vehicles with catalytic converters. Regards, Shell Technical"
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None? Not one? Apparently! I wonder how fast they plug up a cat?
I ran Rotella T in my built up 3.4 for several years, and never killed the cat.
Low-zinc oils didn't become common until very recently, in the grand scheme of things. The only thing that made low-zinc oils workable at all was the introduction of roller tappets. Flat tappets need zinc to lubricate the friction surfaces.
[This message has been edited by Raydar (edited 02-12-2014).]
I ran Rotella T in my built up 3.4 for several years, and never killed the cat.
Low-zinc oils didn't become common until very recently, in the grand scheme of things. The only thing that made low-zinc oils workable at all was the introduction of roller tappets. Flat tappets need zinc to lubricate the friction surfaces.
Thats my thinking too, I hear T6 has moly in it too. I ran it the past 2 years, was wondering how much concern is actually justified.
What's the difference between a gasoline engine catalytic converter and a diesel cat? I run Rotella-T 15W-40 turbo diesel oil in my diesel truck with a cat.
The rep who replied to your e-mail is wrong, or it's a "CYA" response for some reason.
Not only does 5W40 Rotella T6 meet API SM specifications (oil for gasoline engines), but it's sold as mixed-fleet oil which means it's specifically intended to simplify fleet maintenance by using it in both gasoline and diesel engines.
[This message has been edited by Steven Snyder (edited 02-12-2014).]
Originally posted by Steven Snyder: The rep who replied to your e-mail is wrong, or it's a "CYA" response for some reason.
Since the EPA pushed to limit the ZDDP in oils used in passenger cars (to extend catalytic converter life, and maybe to enable them to reach lower levels of emissions) and they didn't reduce the ZDDP in that brand of oil, they probably can't "market" if for passenger car use anymore.
Using it in Fiero with their older style cats and higher emissions standards won't cause any issue, because they have been running with the additive since day one.
Using it in a 2014 car (newer cat design, lower allowable limits) with annual emissions testing might cause it to fail an emissions test sooner, so use it at your own risk.
That is a S**T answer to a very good question........, I see this question playing out on the Hotline, (same question being ask)....Phone attendant ..let me ask someone in technical.. (leans back over her shoulder and shouts .. (DOES IT WORK IN A GASBURNER?) Voice in the distant yells (NO) Phone attendant ... Well there you go... , Have a nice day.....
Since the EPA pushed to limit the ZDDP in oils used in passenger cars (to extend catalytic converter life, and maybe to enable them to reach lower levels of emissions) and they didn't reduce the ZDDP in that brand of oil, they probably can't "market" if for passenger car use anymore.
Using it in Fiero with their older style cats and higher emissions standards won't cause any issue, because they have been running with the additive since day one.
Using it in a 2014 car (newer cat design, lower allowable limits) with annual emissions testing might cause it to fail an emissions test sooner, so use it at your own risk.
The newest designation for gas engine oil is API SN, which is for 2011 and older engines (and anything newer that says to use it). Rotella T6 has the API SM designation, which is for 2010 and older engines.
ZDDP, manganese and sulfur don't plug the cat- it poisons the surface so it's less effective.
For a Fiero and other 80s vintage cars, it's almost irrelevant because the emissions standards for these cars is so lax.
In a 1980s car, feel free to run whatever oil you want. Even if that becomes less effective, it's not going to set a check engine light and you'll probably still pass emissions provided the rest of the car is in good operable condition. I passed the sniffer (when I lived in Houston) in a 1989 Grand Prix 2.8 5 speed with no cat.
[This message has been edited by KurtAKX (edited 02-13-2014).]
ZDDP, manganese and sulfur don't plug the cat- it poisons the surface so it's less effective.
Good to know. Wonder if it would set off a check engine light in my other driver a 96 Sonoma, which has an 02 sensor after the cat. Considering the oil is apparently SM rated for 2010 and older engines it must be fine? Does moly have any negative effects?
[This message has been edited by 2.5 (edited 02-13-2014).]
ZDDP (zinc additive) 1) is NOT needed if the engine has roller lifters. older engines or engines built with flat tappet (solid or hydraulic) need ZDDP additive to prevent accelerated cam wear
2) If ZDDP does affect the performance of a catalytic converter you will not notice anything unless it is a newer car. they run much tighter tolerances on the cat converter performance. hondas are the worst.
remember the oil companies don't care if you engine fails, their lawyers are better than your's.
i can't say exactly, different companies started tightening the specs on the cats at different times. some cars are marked LEV or ULEV those should definitely not have ZDDP. IMO don't run it in any engine with roller lifters, it's not needed therefore a waste of money. fiero 2.8 has regular lifters and therefore needs zinc in the oil, damn the cat. iron duke from 86 and earlier needs zinc. 3800 do not 3400 do not sbc might depending on cam selection. LT1 do not LS series do not.
Newer is kind of vague. Any car with an O2 sensor downsteam of the cat? Or what.. 2012+?
Don't know about other makes, but GM OBD2 systems monitor the ability of the catalytic converter to store oxygen (this is a normal function of all catalytic converters, regardless of when they were manufactured). Starting in 2001, GM added a number of extensive catalyst diagnostics to their PCM tunes that actually test the ability of the catalytic converter to store oxygen several times per trip. It is because of these tests many people have run into issues with cheap / aftermarket replacement catalytic converters on regular street vehicles - in that they cause a low catalyst efficiency code to set once the new / aftermarket cat has been installed. I only know this because a buddy of mine works at an auto repair shop that installs a lot of aftermarket (cheap) catalytic converters and they run into this issue often, mostly with the 2001-newer GM cars. Seems to be a much more common problem with GM CAN-Bus ECMs (2005-newer stuff, mostly).
In any case, I believe what they think the extra Zinc can do is reduce the effectiveness of the catalytic converter to store oxygen. Of course, this is all going to depend on how much oil the engine burns (all engines burn some oil and pass it out the exhaust, it is just a matter of amount) as well as how strict the catalyst diagnostics are. I do know GM has run into a number of oil consumption issues with their newer engines that have the low tension rings on the pistons, especially on engines with DoD/AFM. A number of auto makers have transitioned to using low tension rings to try to increase fuel economy and this may be a contributing factor to engines burning more oil, and perhaps this may be the reason why the EPA has mandated the zinc content be lowered in oil.
I've got a 1996 Silverado pickup truck with factory dual cats that has over 200,000 miles on it. 70,000 miles of which I have always run an oil that had full Zinc content. The post-cat O2 sensors are still present and so are the factory dual cats. Never had any catalyst related codes set in this truck. Of course, the engine doesn't hardly burn any oil either.
-ryan
------------------ OVERKILL IS UNDERRATED Custom GM OBD1 & OBD2 Tuning | Engine Conversions & more | www.gmtuners.com
most obd2 systems have a downstream O2 sensor to monitor the cat efficiency. a 96 chevy will be very forgiving, trucks even more then the cars. like i posted LEV and ULEV vehicles will be the most sensitive. the zinc additive is not needed in a 96 chevy due to the roller lifters so there is no advantage to using it. no harm either due to older obd system.
[This message has been edited by conan469 (edited 02-14-2014).]
In any case, I believe what they think the extra Zinc can do is reduce the effectiveness of the catalytic converter to store oxygen. Of course, this is all going to depend on how much oil the engine burns (all engines burn some oil and pass it out the exhaust, it is just a matter of amount) as well as how strict the catalyst diagnostics are. ... -ryan
Thanks! I wondered about that too, seems like the only way stuff from your oil can get to the cat should be if you burn oil.
the zinc additive is not needed in a 96 chevy due to the roller lifters so there is no advantage to using it.
The increased Zinc offers more benefits to all engines, not just those with flat tappet cams/lifters. Roller cam engines can benefit from the increased zinc content. You still have direct metal on metal contact wear surfaces in all internal combustion engines, regardless if they have roller cams or not. The zinc helps decrease wear between these parts.
I been running Rotella brand for years in everything. Never a cat problem with the exception of the 60 Catalina "No pun intended" which is pre-cat era.
Spoon
------------------ "Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut
Technically it's the Phosphorus that's limited, not the Zinc. But they both go together in ZDDP so the end result is the same.
quote
Originally posted by 2.5: Wonder if it would set off a check engine light in my other driver a 96 Sonoma, which has an 02 sensor after the cat. Considering the oil is apparently SM rated for 2010 and older engines it must be fine?
The effect, if any, would be over the long term. There's a caveat with following the API rating. The phosphorus limit only applies to 30 grades and below. If this is a 40 grade or higher, then it could be high in ZDDP and that wouldn't keep it from having an SM rating. That said, I don't think Rotella is ever known to be especially high in ZDDP, so I wouldn't be worried about it. They're selling it for newer trucks, after all.
An example of the rating weirdness (admittedly not mainstream) is Valvoline VR-1, which has 1300ppm Phosphorus in all grades. The 10w30 version is advertised as API SH, because it exceeds the limit for any later spec. Yet the 20w50 version is API SM, with no difference in the phosphorus content. The reason 20w50 can get the SM rating is because xW40 and above don't have a phosphorus restriction.
Just to be clear, this does *not* mean that any xW40 is automatically high in ZDDP. Not even close. There's just no API rule against it. That rule is only enforced with 30 grades and below.
