350350

Over the summer my LT1 developed an exhaust leak, only when it's cold. Once it warms up, the leak disappears.

I checked all the exhaust manifold bolts, thinking one or two might have worked loose, to find that the rear most driver's side exhaust manifold bolt has snapped off in the head. By the length of the broken piece that I took out, I can see that the bolt is broken off below the surface of the head. In other words, drilling will be required.

Just from looking at it closely from all angles, I don't see any way to repair it with the engine in the car. There's no way to get straight 'on' it with a drill.

It's not currently more than an irritation, but eventually that gasket is going to burn completely out. I can take the car down over the winter (which is really just January here) and pull the engine if I have to. I have a few other minor things I want to do to it anyway.

But I'm open to suggestions?

RamAir95TA

I'm going to assume a right-angle drill is out of the question. Pulling the head is going to be your best bet.

350350

I wouldn't say impossible, but... it would take a very short bit and a very compact right angle. And even then, difficult to get it straight.

Probably worth a shot before completely disassembling the engine or dropping it out in any case. Have to pull all that stuff off anyway.

96capricemgr

At the very front and rear I know the b-body manifolds use the outer holes and headers the inner.
Might this be a good excuse to put headers on???

I would assume the f-body was the same in regards to this.

Pullngz

You just need to pull the head off, not drop the motor out. Unless you are planning some other work.

Camaro350z28

Scratch that and install headers.

Like caprice said. Headers use the inner bolt hole. Perfect time for headers

96capricemgr

Always nice to use a repair as an excuse to mod.

350350

While I wholeheartedly commend this line of thinking, it's... not in the budget any time soon! Took me almost a year to save up enough $$$ to put *stock* heads back on it, and that still wakes me in the night in a cold sweat... putting stock stuff back on it...

/sadviolin

350350

This has been upgraded from a 'minor irritation' to a 'major irritation' so I'm finally getting around to fixing it.

I think I'm going to pull the manifold off and drill a new hole in it to use the 'inner' bolt hole as Caprice said above. Any reason that won't work?

96capricemgr

I don't think there is room to do that with cast manifolds.

jloshotz

Agreed. I think you'd be drilling into the port section of the manifold, which for obvious reasons would be counter productive. It always seems to be the bolt you can never get to easily, is the one that breaks.

350350

You're both right! *sigh* Story of my life... BUT... I got it apart and used a gasket as a template and drilled a hole there to see. The hole clears the manifold port but there's no room for a bolt head. I'm going to dig up some header bolts and see if the head is small enough that I can clearance out a little channel to get that one bolt in there without making the port wall paper thin. I figure it's worth an hour or so trying it before I break down and pull the head.

Another option is that it looks like if I took out the brake booster and steering column completely, I'd have room to get a drill in there to drill/tap the original hole.

In any case, a lot of work for a minor exhaust leak. But it had finally started spitting all the time and while I just plain hate that sound, it seems like that's bad for the engine too. I'm too lazy to look exactly why. Something about it sucking air in I think?

jloshotz

Not sure to the specifics, but I want to say it isn't good for the exhaust valve. But I'm with you, HATE the noise

Black 97 SS

If you can find someone who can weld and you can at least see the end of the bolt you can have someone weld a nut on the end and than turn it out. I had this happen on a old monte carlo I was putting headers on for a friend. This was the only way we could get it out. Drilling is your other option but you probally wont be able to fit one in there.

If you do try this, after you weld the nut on I would use PB Blaster on the bolt for about an hour and than try turning that out. You can also heat the bolt and freeze it to break the rust loose. Loctite or 3M makes a product that you spray out of a can that is extremely cold and should shrink the bolt small enough to remove it.

Good luck

Injuneer

Fix the leak.... it's not "minor". The leak allow air into the exhaust and messes up the O2 sensor reading, causing the PCM to add fuel the engine doesn't need. And if you have any serious reversion, the exhaust valve could burn.