Seafoam leads to Cat failure DTC?

Anyone have problem with Seafoam killing catalytic converters or O2 sensors on OBD2 cars? I haven't run it yet and am hesitant to do so.

Nope!

I can see a sliiiight issue, if it frees up enough carbon to clog your cat because the engine is so dirty, but I highly doubt you will get chunks that large.

If it clogs your cats, they were ready to go anyway.

I've only ever heard of it fouling spark plugs(if run through the engine)......should be fine

I've run SeaFoam services on dozens of cars, most of them late model, and never had a problem. You'll get plenty of misfire and possibly fuel trim faults during the service, but they have always cleared out after the service.

It says that it is O2 and catalyst safe on the can, for whatever that is worth

Never an issue here either. I've done it more than a few times.

I've only done it on one car (the Volvo 850, which is OBDii) and it didn't give me any problems with the cats.

Did it on a Duratech 2.5L and GM 3.4L.

No long term problems, just lots of white smoke.
Make sure its late at night when the neighborhood kids are inside.

I've done it mostly on Audis, VWs, and BMWs. Those cars are always looking for an excuse to fail a cat or O2 sensor, but no problems yet.

Does a 92 Nissan count? That survived it.

Maybe I'm doing it wrong, but both times I've seafoamed (Jeep Cherokee, Toyota Supra) I've needed to replace an O2 sensor directly afterwards.
(I even uncharacteristically followed the instructions)

I have used it on over 100 cars. Lots of smoke but no bad cats or O2s.

SnowMongoose wrote: Maybe I'm doing it wrong, but both times I've seafoamed (Jeep Cherokee, Toyota Supra) I've needed to replace an O2 sensor directly afterwards. (I even uncharacteristically followed the instructions)

The general consensus in my realm is that Seafoam should be run through the engine twice; first time to clean the engine, second time to clean your O2 and plugs.

I have never ruined a cat or O2 sensor by Seafoaming.

I had the cops called on me when I did it in the rx7 that runs premix, there was lots of loud noises and a wall of white smoke moving down the street, dogs were barking. People to their front doors in confusion.

Also when it was hunting idle, it would puff out immaculate massive white smoke rings from the dual exhaust...

SlickDizzy wrote: The general consensus in my realm is that Seafoam should be run through the engine twice; first time to clean the engine, second time to clean your O2 and plugs. I have never ruined a cat or O2 sensor by Seafoaming.

Guess your neck of the woods is more thorough than mine, I'll keep that in mind when I foam my 'new' miata.

The main thing is to get everything up to operating temperature. this will help burn off an residue. the only thing I have heard that can kill an O2 sensor is the fumes from RTV plus leaded gas.

N Sperlo wrote: If it clogs your cats, they were ready to go anyway.

Exactly this.

If you're concerned about it, follow it with the same exact procedure using Heet (fuel system antifreeze). Some people say that it removes carbon from cats.

Just did it to my 96 miata. No issues.

I'm not sure why anybody would want to pour snake oil into their intake, or in their crankcase anyway.

Zomby Woof wrote: I'm not sure why anybody would want to pour snake oil into their intake, or in their crankcase anyway.

because it can break up deposits and get them outta there. it does work.

i prefer Marvel Mystery oil, myself, but only because it's the only stuff i've ever used and i have documented better gas mileage from doing it..

Zomby Woof wrote: I'm not sure why anybody would want to pour snake oil into their intake, or in their crankcase anyway.

If we're talking about the sucked-in-through-a-vacuum-line-through-the-intake application, it does work, but it's less about the chemical and more about the process. Even water will do. It's essentially a steam-cleaning of the cylinders. Just consider how clean a cylinder looks after a head gasket leak.

Marvel Mystery oil leans the intake charge when used in the fuel. Some cars like it, some don't.

m

I'm thinking about using this on my 220k mile focus. Do most of you put it through the vacuum line or fuel tank?

I put it through the vacuum line. The only thing that gets added to my crankcase is Marvel Mystery oil.

Top of my engine looks like this after 135k

Too bad AC deleted his post.

I think most additives, especially these types you're talking about, are snake oil.