Can A Catalytic Converter Be Cleaned?

I used one cup of liquid dishwashing soap and one quart of Harbor Freight heavy-duty cleaner as a cleaner and defoaming agent. "All the other cleaners were a waste of time and money". And a small pond pump and some rubber tubing to circulate the solution through the cats for about three hours each and used the garden hose to get out the residue. Host each cat down with one can of carburetor cleaner. It has worked great for three years now! Unless the internals of cats turn loose and renders them unusable all you have to do is wash them out they don't go bad they just get dirty on the inside.

I followed Scotty's recommendation with the lacquer thinner to a tee, and it worked beautifully. Many people are not running their engines for 150 miles at high speeds and running that tank completely out immediately and then refilling it with a fresh tank and running it some more. Not doing these will cause the problems.

Lacquer thinner worked great on my truck. I poured it in the gas tank. Cleared my P0420

The soap is definitely making a difference. Water only wouldn't get into the hydrophobic fine carbon. The soap breaks the surface tension and helps break up the fine carbon particles. Just my 2c.

The cover is aluminized (aluminum coated steel), which is why the Sodium Hydroxide was dissolving it; you can see that the finish on the heat shield looks much more dull after being soaked in it.

The cleaning videos, like Scotty, said, "...try cleaning the catalytic converter first to clear the p420 code." It's easy and cheap. Then they mentioned, if those techniques don't work, do the bulk work (remove converter) and bulk spending (replacing coverter). What is wrong with trying? It worked in many cases because most converters don't get to that state before throwing a code and the light amount of carbon dust in the c.c. will burn and blow out.

I took off my o2 sensors before the catalytic converter and blew a can of that Seafoam Spray Top Engine Cleaner and Lube used about half each side. It cleared my codes and I haven't had them come back yet. It's been about 8 months since that treatment. I figured that spray is made for specifically for motors and it blows through the catalytic converter anyway so can't harm to much and if it does I'll just cut them out until I find an affordable one that is reliable. Luckily it seems to have worked enough to buy me another year to find one. I also soaked my o2 sensors in berryman b12 for like an hour which cleared 1 of the 2 codes related to that. This guy is experimenting with the CaT he plans on using when he should've used a dummy one just to test what effects it has on the metals. For all I know I could've just melted all the metals and blew them out my tail pipe but hey no codes right haha.

I am pretty sure he just had a bad downstream O2 sensor, seen it before and he never really tested to see if replacing the downstream sensor would have fixed the issue. Never used laser temp reading on upstream and downstream, yes the propane test showed that both sensors reacted, but still say a bad downstream could account for that.

Thanks Fifties Kid! Your thoroughness and patient effort is much appreciated.

I had the "low efficiency" code. Soaked the converters for 2 days in water with dawn dishwashing soap. Changed the solution a couple of times. Rinsed well and the code went away. But, this may be a special case. The head gasket blew and several gallons of coolant went thru the exhaust. A few months after the gasket was replaced the code appeared. The converter on that side (V6 engine) was covered with a white layer. The other converter looked fine. 230k miles, original converters. 3k miles since the cleaning. Downstream O2 sensors are giving a flat (expected) output. So, I can confirm that if the cause of the problem is coolant in the exhaust, soaking with dishwashing soap works.

I think the best solution to a less than efficient cat. (unless it's been poisoned or cooked to death) is the Italian tune-up. I had a 5 Series BMW that failed the MoT emissions test on CO by some significant margin. On the recommendation of the MoT tester I took it to the motorway and gave it serious grief and brought it back to the test station where (once it had cooled down a bit!) it flew through the emissions with no issue at all. I suspect the success of some of the commercial cat. cleaners is the way an Italian tune-up is included in the instructions.

Toluene is in octane booster and Toluol (Toluene) is a very fast drying solvent used for thinning paints, enamels, varnishes, and alkyd resins. Often specified as a thinner for specialty paints and coatings. Good general purpose cleaner and degreaser.

I did this trick one time I use blue Dawn dish soap and a 5 gallon bucket build with hot water. Then I got my air compressor with a extended blower nozzle. With a restrictor at the end of the nozzle. Then I introduced air bubbles to the bottom of the cat. Then all of the built up suit and debris bubbled up through the top. Then I repeated the process five or six times and the cats were cleaned out.

Very intensive practical tests and couldn't agree more on the drive cycles. The mil light governs the result, on, grand off,trouble. Increasing the engine speed shows the cat in its true colours.

That oxygen storage test is gold! I learned something.

I didn't use lacquer thinner BUT I did use a store bought chemical specifically for this and it worked ! So, the lacquer thinner seems plausible.

My 2005 jeep TJ was showing the same codes. I put the scanner on it and the o2 sensors were behaving the same way. Thanks for the help. That confirms my suspicions of a shot converter.

I tried pouring lacquer thinner into one half a tank of fuel and driving the vehicle non stop for 130 miles on the highway. After forty miles the symptoms associated with cat codes for front 1 & 2 cleared and acceleration lag that had been happening disappeared too (bonus)! Say what you want but my 2005 Nissan Pathfinder has had a cat code since 70,000 miles. It now has 228,000 miles and all codes clear. I am writing this a tankful of fuel and a week later. Seems to have worked for me and I actually tried it...

The lacquer thinner does fix the problem. Nothing wrong with Scott’s video.

I subscribed because of this very objective video. Many more please!!!