Exhaust Manifold and cover problems

[NissanSupraGTR]

Well I (painfully) installed a new o2 sensor in my 240 and had to take the exhaust manifold cover off to do so. I noticed that some bolts were missing from the manifold - the ones that connected it to the block. The first section (the first two valves?) is connected by 4 bolts, but the second section only has 1 bolt. I don't know what happened. It looks solid and feels solid, didn't notice any holes or anything, is it ok to leave it like this? Also, when putting the manifold cover back on, 2 bolt heads came off on me, so only 2 bolts are holding the cover on. - Is this also a problem?

[cattrikk]

as long as theres not an exhaust leek, it should be ok, but even still, it wouldnt hurt to fix it. b/c it may start leeking someday. and the cover shouldnt matter either, at most, it'll just rattle at high revs...

[Driftcardotnet]

I have this problem, I noticed them missing a while ago, and up until a few weeks ago my car started sounding like it had an exhaust gasket leak, and at first i thought it was the clicking of the valves, but no this is like this after it warms up. i am not sure what causes this, but i'm sure nissan will charge a lot for it.... [email protected]