Driven correctly - especialyl heating up the car and converter to full operating temp for 10-15 minutes would prevent any need. Can't imagine it is anything but snake oil. Meanwhile the converter on my 2001 330i is 269,500 miles old and no issues. Doubt the previous owners added any cat cleaner and I have not since I got it at 150K miles..

 

Pretty sure the material in the cat gets used up...not dirty.

 

interesting, I've heard of fuel injector cleaners. first time hearing of cat converter cleaner that's added to gas. hmm

 

If you do not have a problem or need for it, do not buy and use it.

Converters tend to get clogged up and compromised due to ash buildup, oil consumption or continuously running the engine with misfires and/or poor fuel trims. We have had many members with problems as early as 100k or less or some go over 250k miles or more before issues come up.

It has to do a lot with maintenance, oil consumption and the way the car is driven. Converters can be compromised, not work efficiently enough and not be clogged or restricted and then there are cases where the converters are restricted or clogged to the point it impacts the engine performance.

Maybe, just maybe in some cases the additive could help in a case of efficiency being compromised but do not expect miracles and do not expect this type of additive to solve restricted/clogged converters.

I would recommend a good long drive down 1 gear with the engine running about 3000-3200 RPM to attempt to clean up converters that may be down on efficiency. Maybe a 1-2 hour drive, not sure this will solve anything, but this is about the best you can do, run a lot of air though the exhaust and hope to heat the converters up to burn off anything that has not burned off during normal driving.

 

Catalytic converter cleaner

Many thanks folks for all your input. I more or less though the same.

Thank you.

 

I had a cat related code on my e36 and added a bottle of 'Guaranteed to Pass', cleared the code and it hasn't come back. Maybe a fluke, but that's my story.

 

I can vouch for this. My local BMW shop always puts a can of 44k in the fuel every visit. They love using it because in addition to being a fuel system cleaner, it is also a cat scrubber and will "cure" mild cases of buildup on the precious metals that throw codes.

Mind you, if your engine is burning oil faster than bp was leaking it into the gulf, perhaps this will not work for you..

 

They love using it because it's an easy mark-up, and it might occasionally clean out the fuel system. It's not going to do anything to useful for the cats.

The stuff that builds up on the catalyst is *really* tough. It's pretty much a ceramic coating. A can of Stoddard solvent and naphtha isn't going to touch it.

Try etching away the deposits on a well-used upstream oxygen sensor shroud and you'll gain an appreciation for how tough the coating is.