Minimizing danger to the catalytic converter in an oil burner?

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I have a car that burns a quart every 1200-1500 miles depending on grade . I have read here that excessive oil burning can lead to catalytic converter failure, so are there particular characteristics I should be looking for in an oil to minimize the danger of ruining my cat? Any brand in particular that has less bad stuff in it? I assume I should avoid non S-rated HDEO because of the high zinc content, right? Anything else?
 
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A thick basic SP oil should do. A syn blend 20w-50 is probably your best bet. But what oil grade are you using right now for it? if its a 5w-20 then a 10w-40 should do just fine. Have you also tried to find a solution for the consumption?
 

JTK

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I don't think it's the oil itself, it's trying to minimize the oil burning. I'd try the heaviest viscosity it will tolerate.
 
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THinking out loud. SP rated oils were developed in order to prevent LSPI - which is to say the oils ignite at a higher temp - correct?

Isn't this exactly opposite of what the OP is asking for - so he should look for something that doesn't offer much LSPI protection - so it can burn off?

Do I have that right?
 

Elkins45

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A thick basic SP oil should do. A syn blend 20w-50 is probably your best bet. But what oil grade are you using right now for it? if its a 5w-20 then a 10w-40 should do just fine. Have you also tried to find a solution for the consumption?
I was burning a quart every 300 miles when I bought it. I replaced the PCV valve and did a piston soak plus BG 109 and some short interval changes to improve it to the point where it is now. It’s a Toyota 2az-fe so it was a defective design from the start. I’m just trying to keep the CEL from coming on should I ever decide to sell it. We don’t have inspections where I live so that’s fortunately not a concern for me.

Right now I’m running a dual-rated 5w-40 HDEO hoping it might clean it up just a bit more. With winter coming I think my next change will probably be to a 5w-30 just to see if it makes a difference.
 
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I was burning a quart every 300 miles when I bought it. I replaced the PCV valve and did a piston soak plus BG 109 and some short interval changes to improve it to the point where it is now. It’s a Toyota 2az-fe so it was a defective design from the start. I’m just trying to keep the CEL from coming on should I ever decide to sell it. We don’t have inspections where I live so that’s fortunately not a concern for me.

Right now I’m running a dual-rated 5w-40 HDEO hoping it might clean it up just a bit more. With winter coming I think my next change will probably be to a 5w-30 just to see if it makes a difference.
You should try a 20w-50. Just let the engine run for a minute before going off so the oil has plenty of time to circulate and be lighter on the throttle at first which is what i do. How cold is it during the northern Kentucky winters when you start the engine. About 30f or so? I think a 20w-50 would still do fine at that temp. I've started 15w-40 in lower temps and it was fine.
 
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Castrol high mileage claims to have an additive package specifically designed to reduce harm to catalytic converter when the oil is burned but how much of a difference it makes is debatable.
 
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I was burning a quart every 300 miles when I bought it. I replaced the PCV valve and did a piston soak plus BG 109 and some short interval changes to improve it to the point where it is now. It’s a Toyota 2az-fe so it was a defective design from the start. I’m just trying to keep the CEL from coming on should I ever decide to sell it. We don’t have inspections where I live so that’s fortunately not a concern for me.

Right now I’m running a dual-rated 5w-40 HDEO hoping it might clean it up just a bit more. With winter coming I think my next change will probably be to a 5w-30 just to see if it makes a difference.

When you did the BG109 did you use new oil? How long did you run the BG109? If you have gone from using a quart every 300 miles and now it uses a quart every 1200 to 1500 miles I would use the BG109 again.
 
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If you’re worried about an after-cat cel put the after cat sensor in an anti-fouler spacer ( I bought mine at autoze) then put it back. Itll stop those cel lights. My ‘96 pickup has no cat at all and the anti-fouler trick stopped the cel’s point blank.
 

Elkins45

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This is your Scion xB? I just pulled up your old thread about it an hour ago. Is it holding at the oil useage since you did your fixes?
Yes, it is. I’ve driven it about 10k since the piston soak and it’s gradually improved up to where it is now and seems to be holding steady.
 

Elkins45

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When you did the BG109 did you use new oil? How long did you run the BG109? If you have gone from using a quart every 300 miles and now it uses a quart every 1200 to 1500 miles I would use the BG109 again.
I did it 1000 miles after new oil following a piston soak. It was the piston soak that made the biggest difference but the BG gave me another 200-300 miles I think. I let it idle 30 minutes before dumping it.
 

Jackson_Slugger

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I was burning a quart every 300 miles when I bought it. I replaced the PCV valve and did a piston soak plus BG 109 and some short interval changes to improve it to the point where it is now. It’s a Toyota 2az-fe so it was a defective design from the start. I’m just trying to keep the CEL from coming on should I ever decide to sell it. We don’t have inspections where I live so that’s fortunately not a concern for me.

Right now I’m running a dual-rated 5w-40 HDEO hoping it might clean it up just a bit more. With winter coming I think my next change will probably be to a 5w-30 just to see if it makes a difference.

If it's the 1.8L using heavier oils can actually accelerate burning in some of these because the oil can no longer circulate properly. I'd go opposite and try a 0W-20 HM or 5W-20 blend HM oil. I think there is a fix that involves opening her up and internally cleaning as well as drilling additional pinholes. You can also add a cleaner like Rislone or HPL Engine Cleaner...

There are also a few cat cleaners out there, but not sure how effective they actually are. I'd consider using "Guaranteed to Pass" as a FI cleaner if you use FI cleaners...
 
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