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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[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 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.

[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.