2006 XC70 catalyst loose

[saq]

I evidently waited too long to look into the reduced power on the 06, and while the hydrocholoric acid soak removed all the sufate buildup from the PCV oil dumped in the intake, the oxidation catalyst had been displaced backwards and evidently enough that the insulation material holding it in place came loose and blocked the reduction catalyst. Took it off again, hosed out the debris, but now the oxidation catalyst block is loose, which means if I put it back on the car it will likely break itself up.

I know the offical answer (buy a new $2500 Volvo converter! - ain't happening) and the unofficial one (remove it - no more problems!) but I do remember how much the air has improved since the '80s... so...

Is the catalyst held in with just a mineral wool friction fit? IF so I could get wood stove/forge insulation (possibly braided) and open the cat and rewrap it, then either braze or weld the cat back in place - or I could hold it in place with long stainless steel screws, potentially, which would mean I don't have to figure out if the braze metal will melt under operating conditions or whether my welding skills are good enough for the cat sheet metal.

Anyone else had this problem and fixed it?

[Vova585]

Maybe utilize the pipe from original one, try to find aftermarket replacement which will be similar in size to original for way less money(lets be honest here it will not be great and likely will not be able to store enough oxygen, but better than 80's..ofcourse you will need non-fooler extension for rear O2 and ofcourse you will only drive it on farm land to obey all local and federal laws).

[chrism]

……. or I could hold it in place with long stainless steel screws……

Ever since our old 740 suffered a loose rattling honeycomb in the cat I’ve wondered if that fix would work and for how long. It would be interesting to try.

[saq]

Ever since I acid washed it it stopped throwing catalyst efficiency codes, so it works just fine for emissions, just need to hold it in place so it doesn't destroy itself.

My big concern with the screws is how well it would hold. On mine the front catalyst had been driven back about an inch onto the converter mounted O2 sensor, so there is significant force at play in those things (granted it was partially blocked, but still there is lots of force).

[MoVolvos]

Ever since I acid washed it it stopped throwing catalyst efficiency codes, so it works just fine for emissions, just need to hold it in place so it doesn't destroy itself.

My big concern with the screws is how well it would hold. On mine the front catalyst had been driven back about an inch onto the converter mounted O2 sensor, so there is significant force at play in those things (granted it was partially blocked, but still there is lots of force).

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If it's not too difficult to remove just shake out the broken pieces and drive on till it further breaks or throws a code.
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[saq]

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If it's not too difficult to remove just shake out the broken pieces and drive on till it further breaks or throws a code.
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That's the weird thing, everyone talks about broken honeycomb, but it is absolutely intact, just slipped out of the support material and is loose in the casing.

[MoVolvos]

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If it's not too difficult to remove just shake out the broken pieces and drive on till it further breaks or throws a code.
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That's the weird thing, everyone talks about broken honeycomb, but it is absolutely intact, just slipped out of the support material and is loose in the casing.

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Push backwards till it wedges or back to original position and tap 4 SS screws from the top on both sides 2 front and 2 rear to keep it in position. If you use the screws on the bottom it may not pass inspection.

(EDIT: Do not drill into the honey comb so as not to crack it.)
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