Ash free.
What Oil Type To Protect Catalytic Converter?
- Thread starter Nessism1
- Start date
It’s the ash that poisons the catalyst? I thought it was the phosphorus?
What’s a good ash free oil to use?
“ZINC” is the problem?
Castrol markets its oils, or many of its oils, as low in phosphorus, and that they can help protect catalytic converters.
You already know where I was going with this. Ash free means little to no antiwear additives and detergent.
The zinc, phosphorus, calcium, ect is what cloggs the catalytic converter.
There is no good ash free oil if the engine is ment to last.
The ash is a necessary evil if you want oil with detergents that can go well beyond 3,000 miles and and antiwear additives if you want engines that easily last more than a hundred thousand miles.
Best bet is to flange in the catalytic converter and clean it or replace it before an emissions test.
With the prices of platinum and palladium lately I wouldn't want to be buying one.
Is the OP's converter clogged with ash? Is that the problem here?
Is there even a problem at all?
Only if you're in a smog state.
I think he said he is in California so running without a catalytic converter isn't going to fly there.
If my vehicle clogs a cat I'll implement the final solution.
Perhaps he’ll find one of those ash free oils and prevent converter clogging from the phosphorus.
edyvw
$50 site donor 2026
Smog state? What are non-smog states? CO has smog tests in Denver, but not herein Colorado Springs. Numerous examples like this around country.
I didn't realize so many states require smog checks...
Edit: Apparently, this graphic is misleading, since some states only have regional testing, not full state testing.
Edit: Apparently, this graphic is misleading, since some states only have regional testing, not full state testing.
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edyvw
$50 site donor 2026
All modern oils in the last 30 years are CAT compatible. 100ppm of phosphorus won’t matter that much.
The stink behind some car is not necessarily failed CAT. It could be that person doesn’t have a CAT at all.
If not burning oil, forget about it, or get Euro approved pils with MB229.5 or .51/52 that have Noack limit at 10%.
About 99% of the land area of new Mexico does not require smog testing.
edyvw
$50 site donor 2026
CO is listed. But not all counties. Only few. Same goes for NV and GA.
Same goes for Missouri. Only the St. Louis area requires smog testing, the entire rest of the state including Kansas City does not.
Do you think that API's limits on phosphorus are meaningless? That spec is there to protect CATS. Some Euro oils don't qualify for current API certification because their phosphorus levels are too high. Do you think there should be limits, or no? Or maybe the API limit is too low?
OVERKILL
$100 Site Donor 2021
It's a combination of the permitted volatility level, which is inherently higher with thinner oils, and the amount of phosphorous. That's why grades 40 and up are exempt, as they generally have much lower volatility.
This is why thinner Euro oils, where volatility is limited more than under the API, are permitted higher levels of phosphorous.
this isn't accurate, in NY you do not have a "smog test" all that's done is the make sure your CEL isn't on, and a visual check to make sure everything is in place. And when the vehicle turns 25 years old, it's exempt. Like my 98 Grand Cherokee.
I was implying to the assumption of the vehicle you were assuming in your story.
As for catalyst failures there are many factors other than oil itself.
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