Welding exhaust manifold on car

My Subaru has a crack around a weld on the header/manifold. It is easily accessible from under the car. Is there any reason to remove it if I want to attempt welding it?

The crack is almost all the way around the weld in the picture.

I've done it- works out ok. Scary, but it was a challenge car without much in it, but time.

For your job- how clean can you make that area?

And, while obvious, it's good to remind you to disconnect the battery.

I've had almost all of my exhaust welding done while the exhaust was attached to the car, including fabrication of a custom catback system.

Clean it up good. But upside down welding sucks!

Appears kinda thin and looks like a crack toward the right of the pipe in photo. Clean real good like others said. If MIG, don't get too happy w/ the trigger, pulse it.

I'm assuming we're talking electric welding, and it's fine to weld in-place - just make SURE to attach the ground to the exhaust pipe! If you just clamp it to the frame of the car, the welding current may flow through wires not intended to do any such thing.

I got it as clean as possible. It is going ok so far. Just doing a couple tacks at a time with the mig.

Thanks for the input. I've never welded exhaust this close to the engine so i wasn't sure if there were any unusual things to be aware of.

Could you put a gusset around it? I have a spot like that on a Nissan Pickup that cracked continually. I took a piece of exhaust pipe about 2" long, split it, spread it and beat it flush. Then I welded the seam completely and stitch welded the top and bottom of the patch to the downpipe. It has lasted for several years.

I got it all welded up and it doesn't seem to be leaking any more. We'll see how long it lasts.

I've heard pull the negative battery cable, but never seen, nor heard of a muffler shop doing so.