Changing a catalytic converter

[mickburkesnr]

Just a quick one. I need to change the catalytic converter in my 107 (identical to the Aygo), and I've the two gaskets and converter to go on the car.

Question is, do I need to apply any glue or sticky stuff to the gaskets before I put them on? Or will the compression be enough to seal the converter to the revelvant holes?

[Agent Orange]

Hi Michael,

I have to say that I have no experience whatsoever of changing a catalytic converter but I am a big fan of "Wheeler Dealers".  On that show the brilliant Edd China brings cars back from the brink and if he ever changes an exhaust or fits any gasket, he always uses some kind of "Sticky Stuff".  It could be exhaust paste on a tail pipe, or silicone on another gasket but he always recommendes using something and then not overtightening any bolts as this might crush the gasket.

Like I say, I'm not the person to ask about catalytic converters but I have overtightened a few bolts in my time and I'm a big fan of the "Belt and Braces" approach.

I hope that helps in some way, good luck and all the best! 

[mickburkesnr]

I've seen some videos of guys doing this on their 107/C1/Aygo's and they dont seem to use any glue or mastick stuff. So I'm going to go along the lines of it uses compression. I found the original cracked converter I used to have on it and there was no glue/gunk residue on it so I'd say - unless the garage was very clean - it doesn't need it.

Totally agree on the Edd China thing, he's the only reason I've bothered to do any work like this myself. 

While I was driving the car I did notice the back box sounded knackered. I've had it since new, and it's 7 years old this year so I thought I'd change the back box too while I'm at it. While picking the back box up I found the thing I thought I needed - Firegum. You stick it on the pipes to help fitting them, and it then seals the pipe.

[Agent Orange]

Firegum!...If it's blue, then that's the stuff, Michael.  I couldn't think of the proper name, so I said exhaust paste but I've seen Edd China wipe it on (Orange Gloves on first, please!) many an exhaust.

Talking of the Tall Guy, he is leaving "Wheeler dealers"   Mike Brewer is staying on but with that Ant Anstead (I think that's his name) chappie.  Edd made no bones about why he is leaving as the producers of Wheeler Dealers are "Dumbing it down" with less Workshop bits.....It seems the American market doesn't like those!

Like you, I'm a big fan of Edd and love all his tips, tricks and "How-To" explanations. Seems like I'll have to watch out on You Tube for any more of those.

Take care. 

[Planemo]

Neither joint is supposed to have sealant. The factory laminated steel gaskets used between head and manifold joins are brilliant these days (just as laminated head gaskets). The mesh olive used between the maniverter and exhaust is crushed to the right amount by the springs at the joint. Neither should ever leak.

Only if the maniverter has a poor sealing face (due to rust/warpage) would I consider using any sealant but I would flat it off first with a straight edge just to see how bad it was.

The old days of horrible cork sump gaskets and composite head gaskets are thankfully long gone. I ran my Supra at twice stock power on stock gaskets and never had a single problem :)

[mickburkesnr]

I had such a nightmare over the weekend with the car, not with the catalytic converter it went on fine! Did notice - as it was a second hand part - there's small holes in the weld where the manifold meets the cat. I smothered it in some exhaust repair stuff while it was off the car so it sealed the holes. But I'll be changing it again in a year I think as it's going to go the same way as the old one did. I didn't put anything on the gaskets, I reasoned that when it came off there was no sign of sealant so I didn't bother putting any on.

As for Edd China, I think he's completely right. He has built a reputation on doing things properly and methodically, so cutting back on important jobs will hurt him. That's not to say Ant Anstead is slapdash, far from it if you've seen him on "For The Love Of Cars", but he's a relative unknown compared to Edd so he can afford to do it if that makes sense?

[Agent Orange]

It makes perfect sense, Michael and I agree with you, I quite liked "For the love of Cars" (My favourite was the old Saab 94) but Ant Anstead never went into detail like Edd China, or seemed to care anything like as much as Fuzz Townsend on "Car S.O.S"

As you say, Ant Anstead is a relative unknown and for anybody that has taken an interest in this thread, you can check him out in a new series called "The World's most expensive Cars" on Channel 4 at 4.30pm from Sunday 30th April.

I'm glad that you finally got your exhaust sorted out, Michael, but that does sound like a very frustrating weekend that you've had there.

Keep Smiling! 

[mickburkesnr]

Got to do it all again on my 19 year old Corolla. The cat, middle and back boxes. That's going to be fun!

At least in that case there's a lot more room underneath, meaning the only problem I'll have is rusty crusty bolts that should fall off if I hit them enough.

It was frustrating, but now I know what goes in to it I'll be a bit more prepared next time.

[AdamCambourne69]

You need to use an exhaust cement.

Adam

[eygo]

i have been told never to use sealing compounds before a catalytic convertor

as the compund can damage the convertor if any excess broke free and fell inside.

 

[SAM LOVERS HER TOYOTAS]

I fitted a new c.converter this year along with new mid pipe and silencer box...new gaskets and bolts etc...and i can confirm...no glues or pastes or anything of the sort are required. 

Sammy

 

[Wolds Warrior]

Yeah ill just have my 10p worth...

Fitted a new cat to my Aygo, no sealant needed at all, and thats how id expect it with 95% of exhaust components on cars.

Gaskets are designed to expand where needed, and a dry joint that fits well, its much better than a shoddy fitting one with Exhaust paste.

I get some Aftermarket exhaust pieces are not a very good fit, but the majority are fine nowadays.

Cheers

[MatthewMorris33]

I have just changed my catalytic convertor. Here is the one I brought off ebay https://ebay.us/b0vrZV.

[TonyHSD]

5 hours ago, MatthewMorris33 said:

I have just changed my catalytic convertor. Here is the one I brought off ebay https://ebay.us/b0vrZV.

That’s cheap, good job done ✅