my friend just installed a header on his cobalt, and when he was taking of the bolts, 2 of the studs came out with them. we didnt think much about it and just put them back with all the other nuts, and he has a leak. could the leak be caused by those bolts? the leak isnt coming from the side where they came out.

and also, if there is a small leak , could that cause damage??

 

It could be contributed that it's just not torqued good enough and exhaust fumes (doesn't have to be alot) is escaping from even a small area and not down the exhaust system like it should be.

Go to Auto Zone or Pep Boys and buy new bolts. They aren't expensive.

 

I dunno a few of my studs did that too.... never had a leak with mine.

 

The studs themselves should not be the cause of the leak, even if they came out during install. Check your gaskets and torques.

As for the studs, they have an inverted torx bit head on them. They are NOT hex drive. Don't try to screw them back in with a hex or you will strip it. With the right tool, they drive back in and torque down very nicely.

 

what tool? we've taken them out a few times and they havent stripped yet

 

Make sure you're using a torque wrench when you do this. They are just threaded into the head, so it's not a big deal if they come out. Just use and inverted torx socket to screw them back in, using the torque wrench of course.