Oil from AOS in Exhaust

[78F350]

I'm replacing a bad AOS and there is some oil dripping from the exhaust. Is there any concern about cleaning/flushing the O2 sensors or cat's, or is it best to just run the car after replacing the AOS and let the oil just burn off?

[JFP in PA]

Originally Posted by 78F350

I'm replacing a bad AOS and there is some oil dripping from the exhaust. Is there any concern about cleaning/flushing the O2 sensors or cat's, or is it best to just run the car after replacing the AOS and let the oil just burn off?

I wouldn't be worried about the sensors, oil is murder on the cats, which are way more expensive. Fill the car up with fuel and take a long ride at steady cruise speeds (50-60 MPH); this will get the cats hot and keep them that way. If the oil burns off, your golden, it the cats start coding, you are about to spend some $.

[piper6909]

Originally Posted by JFP in PA

I wouldn't be worried about the sensors, oil is murder on the cats, which are way more expensive. Fill the car up with fuel and take a long ride at steady cruise speeds (50-60 MPH); this will get the cats hot and keep them that way. If the oil burns off, your golden, it the cats start coding, you are about to spend some $.

Can't he put the odds in his favor by removing the cats and washing them out with a solution of water & laundry detergent or some other solvent? I've heard of people doing that, but never tried it myself.

[Kboggs]

Originally Posted by piper6909

Can't he put the odds in his favor by removing the cats and washing them out with a solution of water & laundry detergent or some other solvent? I've heard of people doing that, but never tried it myself.

Or if your in a state like NC, vehicles over 20 years dont get emissions tested any longer and you can do a cat delete!


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[piper6909]

Originally Posted by Kboggs

Or if your in a state like NC, vehicles over 20 years dont get emissions tested any longer and you can do a cat delete!


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And put a piece of tape over the CEL?

[Kboggs]

Originally Posted by piper6909

And put a piece of tape over the CEL?

Sure! Same thing I did for the airbag light till I got around to changing the seatbelt clip. I bet there is a way to circumvent the light somehow?


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[piper6909]

Originally Posted by Kboggs

Sure! Same thing I did for the airbag light till I got around to changing the seatbelt clip. I bet there is a way to circumvent the light somehow?


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Once, I actually heard of a used car dealer who would use the smallest diameter drill bit he could find and drill through the cluster and break the light!

[78F350]

JFP, Thanks for the rapid response. I'm going to take it out for some laps around town on the bypass tomorrow, 50-60 MPH as you suggested.

The AOS actually went in very easily. I disconnected the oil filler tube, next to it up top, and the mount for the O2 sensor below and beside it. With cable hose clamp pliers and positioning the clamp in an easy to access position, it went right on first try.


There's no emission inspection here in Oklahoma, but still it's a nice car and I want to keep it correct.

[JFP in PA]

Originally Posted by Kboggs

Sure! Same thing I did for the airbag light till I got around to changing the seatbelt clip. I bet there is a way to circumvent the light somehow?


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Actually, if you removed the CEL bulb, or otherwise disabled it, the computer will throw a special code indicating tampering with the system, which will fail the car. Most states that require inspection also require scanning the car and submitting that data to the state computer in order to pass the car. You cannot simply ignore the problem, or try to cheat the system by clearing the light just before going for inspection, it won't work as the I/M Readiness scan will catch it.

If people spent half the time spent on trying to circumvent these systems on actually fixing the car, you would probably be back on the road already.

[JFP in PA]

Originally Posted by piper6909

Can't he put the odds in his favor by removing the cats and washing them out with a solution of water & laundry detergent or some other solvent? I've heard of people doing that, but never tried it myself.

Doesn't work; what kills the cat is the anti wear additives in the oil, not the oil itself. These additives react with the platinum metal in the cats, disabling the matrix.

[piper6909]

Originally Posted by JFP in PA

Doesn't work; what kills the cat is the anti wear additives in the oil, not the oil itself. These additives react with the platinum metal in the cats, disabling the matrix.

Got it. Thank you.

[piper6909]

Originally Posted by JFP in PA

Actually, if you removed the CEL bulb, or otherwise disabled it, the computer will throw a special code indicating tampering with the system, which will fail the car. Most states that require inspection also require scanning the car and submitting that data to the state computer in order to pass the car. You cannot simply ignore the problem, or try to cheat the system by clearing the light just before going for inspection, it won't work as the I/M Readiness scan will catch it.

If people spent half the time spent on trying to circumvent these systems on actually fixing the car, you would probably be back on the road already.

Kboggs is in a state that does not test cars over 20 years old, so to him it doesn't matter if the CEL is on.

But yeah, I agree with you about fixing the car right instead of circumventing the emissions.

[JFP in PA]

Even in states with no emissions requirements, how are you going to sell or trade in a vehicle with the light on? The very first thing we do during a PPi for a prospective buyer is to scan the car, which would catch any attempt to circumvent the system.

[blue62]

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[Bald Eagle]

I've been reading the many comments from JFP in PA for the years I've owned my Boxster and want to thank him for contributing his knowledge and expertise to this forum. I wish I was closer to PA so I could take my car to him but, I'm at least 500 miles away depending on where in PA he is. Seems like a very helpful, no BS guy and an asset to this community.
Larry (the Bald Eagle)

[flmont]

I would certainly 2nd that statement Thanks !! JFP..for all the time and money saved with your advise..Frank