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  #1  
Old 09-08-2003, 03:00 PM
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Question The next obvious question, can a cat be cleaned?

Did a search and apparently no one has asked this before. Let's say you have a catalytic convertor that has been subjected to excessive oil consumption and then LOTS of raw gas (10 mpg). Is there any way to clean it or are there 'no user serviceable parts inside'?
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  #2  
Old 09-08-2003, 03:26 PM
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Interesting question.

Never heard of such a thing as catalytic converter cleaning, other than those 'miracle' gas additives.
I know from experience that the innards are fragile and brittle, so it is not as if it can be opened up and scrubbed.

Now whether the whole thing could be immersed in a solvent to clean off oily goo without destroying the catalyst- good question...
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  #3  
Old 09-08-2003, 04:20 PM
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There are two thoughts on this subject.
First, if you dump excessive amounts of fuel through the converter, it will glow verrrry red. This in itself would probably result in some kind of " cleaning " action.
Second, again as I stated a while ago, Ford had a recall on my 1988 5.0 Mustang, to replace all 4 catalytic converters because of oil contamination.
When they tried " low tension " piston rings ( to reduce friction ), it resulted in excessive oil consumption, hence destoying the converters.
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  #4  
Old 09-08-2003, 08:27 PM
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elements in large, stationary, ng-fueled, spark-ignited engine cats can be and are cleaned routinely. this is done because these large bore, continuous-duty engines can pass a lot of lube oil additives[ash] in the exhaust that eventually coat the catalytically reactive elements, rendering them ineffective.

this cleaning can be cost effective for this industrial horsepower. whether it makes any economic sense for an automotive application cat would have to be explored. i sort of doubt it would, though.
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  #5  
Old 09-08-2003, 08:32 PM
LarryBible
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Yes, if you start them washing them as a kitten. My wife had a calico kitten that got dirty and she washed it in the sink. It seemed to enjoy a bath after that.

Have a great day,
PS I guess this proves that there is a smart^$$ in every crowd.LB
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Old 09-08-2003, 10:38 PM
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I was waiting on that one, I just never imagined that it would be from you, Larry! Ain't you suppossed to be working??:p
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  #7  
Old 09-09-2003, 12:00 AM
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A catalytic converter can be "overwhelmed" by excess oil and the resulting ash and soot, and once coated, rendering them useless, but not always "burnt out".

If the engine is now at proper mixture, I would think that extended, hot (high RPM) freeway runs might burn some of the old stuff out enough for the catalyst material to finish the job itself.

I've seen gas additive cat cleaner on the JCWhitney site....Snake oil??

Some commercial cats are cleaned by heating in a kiln for 2-3 hrs, at 1050 *F. (I've done similar to this with chem. laboratory grade catalysts).

A technique that I read somewhere? (heavy eqipment site??) involved removing the cat, using Superconcentrate Gunk solution to soak the core for an hour (repeating as needed), rinsing with hot water and finally drying with compressed air. I don't know if this was on a metal foil or a ceramic substrate catalyst, though.

Most cats that are run with excess volatile HCs (propane, gasoline) for an extended period of time, burn up due to the higher than designed heat of reaction and are best replaced.

FWIW
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Old 09-09-2003, 02:30 AM
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Quote:
Originally posted by jbaj007
If the engine is now at proper mixture, I would think that extended, hot (high RPM) freeway runs might burn some of the old stuff out enough for the catalyst material to finish the job itself.
I also had that theory, until my mech told me that the clogged cat would be the very reason the engine would run bad and clog the cat even more..

Perhaps you could take the cat off the car and in some way 'cook' it clean? -Maybe strap an electric heat-gun (one of those to remove paint from wooden doors and windows) for an hour or two? Just a suggestion..

Freestyler
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  #9  
Old 09-09-2003, 04:58 AM
Bud
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Here's someone's post I saved a while back about fixing cats on a 300E. I don't know if it's applicable....

"Your catalytic converter(s) are clogged- probably the small ones in the
front pipe. This happens in a 300E from oil consumption over a long period
of time. A quick cure (other than the obvious one of buying a new front
pipe for $1,200 or so) is to take the pipe off the car, and have a shop
glass-bead the front (engine) side of the mini-catalysts a couple of
millimeters. The clogging seldom goes deeper. Proper performance is
restored without damaging the catalytic effects."
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  #10  
Old 09-09-2003, 09:14 AM
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Quote:
Originally posted by Bud
Here's someone's post I saved a while back about fixing cats on a 300E. I don't know if it's applicable....

"Your catalytic converter(s) are clogged- probably the small ones in the
front pipe. This happens in a 300E from oil consumption over a long period
of time. A quick cure (other than the obvious one of buying a new front
pipe for $1,200 or so) is to take the pipe off the car, and have a shop
glass-bead the front (engine) side of the mini-catalysts a couple of
millimeters. The clogging seldom goes deeper. Proper performance is
restored without damaging the catalytic effects."
Bud, do you know the source of that info?
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  #11  
Old 09-09-2003, 10:10 AM
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I don't remember where I got this. It might have been from the Mercedes Club forum but it was quite a while ago and that forum was a victim of internal politics.

After Frank King passed away and because of the internal strife, I quit the club.
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  #12  
Old 09-09-2003, 10:11 AM
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They can be cleaned with a tire iron. It really restores them to their like-new flow rate or better.

Ken300D
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  #13  
Old 09-09-2003, 10:26 AM
Bud
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Quote:
Originally posted by Ken300D
They can be cleaned with a tire iron. It really restores them to their like-new flow rate or better.

Ken300D
Ken, do you mean by banging on them? I recently had the exhaust replaced on my 300E and the clutz that did it beat on the tail pipe of the cat trying to get the muffler off. He finally used an impact chisel to do it.

After he was done, the exhaust system was noisier than before despite the new OEM muffler and resonator. I assumed he damaged the cat but it passed the emissions test.

There are two kinds of cats, ceramic honeycomb and ceramic beads. Beating on a ceramic bead type might work but I would think it would damage the honeycomb type.

Last edited by Bud; 09-09-2003 at 10:39 AM.
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  #14  
Old 09-09-2003, 10:26 AM
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Quote:
Originally posted by Ken300D
They can be cleaned with a tire iron. It really restores them to their like-new flow rate or better.

Ken300D
But not necessarily to their original catalytic efficiency, right Ken??
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  #15  
Old 09-09-2003, 11:58 AM
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The method I'm referring to applies the tire iron directly to the internal honeycomb. This dramatically improves the exhaust flow.

Ken300D
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