Crack in exhaust manifold

[Derry]

While taking off the catalytic convertor and the main exhaust to renew them, I noticed this crack on the exhaust manifold, looks like the crack is going all the way round that section. No other cracks on the manifold. Just wondering what my options are, can they be repaired with things like JB Extreme Heat metallic paste.
I haven’t noticed any fumes or lack of power when I was driving, can I just ignore it not sure what the consequences would be. With the cost of replacing the exhaust system coming up, I rather try to resolve it without buying a new unit. Any help or suggestions will be much appreciated. Thanks

[volvo again]

There's a few used ones on ebay...

[Bob Meadows]

J.B. epoxy is good but I doubt very much that it can perform on the manifold:~

Cast iron welding is a real art nowadays and potentially costly- however brazing cast iron is a good option and one that will perform well, I've had it done on two post war classics without any problems.
Good luck.
Bob.

[Luxobarge]

Originally Posted by Bob Meadows

J.B. epoxy is good but I doubt very much that it can perform on the manifold:~

Cast iron welding is a real art nowadays and potentially costly- however brazing cast iron is a good option and one that will perform well, I've had it done on two post war classics without any problems.
Good luck.
Bob.

Indeed, brazing it would probably work, but given that you'd need to remove it to do so, I'd have thought that replacement with a used one would be the way to go - probably cheaper in the end too, and quicker. Manifold cracking isn't a common fault on these engines, so a used one is probably going to be fine. I also agree that JB weld and stuff like that is not likely to work for any length of time.

[acshortt5]

Originally Posted by Luxobarge

Indeed, brazing it would probably work, but given that you'd need to remove it to do so, I'd have thought that replacement with a used one would be the way to go - probably cheaper in the end too, and quicker. Manifold cracking isn't a common fault on these engines, so a used one is probably going to be fine. I also agree that JB weld and stuff like that is not likely to work for any length of time.

I've no experience with the N/A engine but when I refurbished my turbo I found the exhaust manifold was cracked, particularly on the inside at the collector. I replaced it with a very good second hand one. It might be one of the reasons why the turbo exhaust manifold was changed in 1999.

I wouldn't recommend trying JB weld or similar as it will possibly very quickly fall out and if it's for cracks on the inside of the manifold if it falls out it will head straight to the Cat where it might cause damage.

I would additionally consider the condition of the engine mounts - if they are worn then you might have quite a bit of engine movement in excess of what the flexibility of the exhaust system can absorb?

Worst case scenario I think you can get new manifolds for the N/A engines from PFV if you can't find a good used one.

[Clan]

Originally Posted by Derry

While taking off the catalytic convertor and the main exhaust to renew them, I noticed this crack on the exhaust manifold, looks like the crack is going all the way round that section. No other cracks on the manifold. Just wondering what my options are, can they be repaired with things like JB Extreme Heat metallic paste.
I haven’t noticed any fumes or lack of power when I was driving, can I just ignore it not sure what the consequences would be. With the cost of replacing the exhaust system coming up, I rather try to resolve it without buying a new unit. Any help or suggestions will be much appreciated. Thanks

It is simply worn out over time , many many heating cycles ... the only way of welding that is whilst bolted up to the head or a spare head or it will crack again straight away . Best get a new one whilst you can if keeping the car ..

[Derry]

Great advice as usual, thank you guys.
I have taken the old one off and the crack is 3/4 of that section so I can't see JB weld stopping it going further. I was surprised how easy it came off and out, not sure why Hayes was instructing to drain the coolent, disconnect pipes, remove top engine mount etc.
PFV have them for £134 + postage. And Rufe can get one for around £250 + postage. I will look around online for a used one next few days while looking for a decent priced exhaust and cat.

[Derry]

Do I need to use any exhaust assembly paste when connecting the front and middle section exhaust pipes, or just the pipe clamp will do.

Like this stuff https://www.eurocarparts.com/p/holts...00ml-552996220

[volvo again]

I always use assembly paste, not sure if the local fast fit guys do though, helps to seal joints and should make it easier if you need to remove a section.
make sure it's asembly paste and not the sealer...

[Luxobarge]

Likewise, I always use a bit of paste, make sure it's dried off properly before running the car though, otherwise it'll just blow out of any cracks it's sealing.