The Stovebolt Site Forums The Shop Area Engine Shop Exhaust Manifold Leak-Couple Of Questions

After getting my 216 fired back up, I realized I have a leaky exhaust manifold. When I bought the truck, the exhaust system was pretty much non-existant so these leaks went unnoticed. There are two leaks, the port in front of the carb has about a .018 gap and the one behind the carb is about .013. Two questions :

From everyone's experience, what is the likelihood that I am going to break off some bolts getting this off? I'm trying to decide whether to do this myself, I really don't want to get into drilling/tapping broken bolts.

Any chance that tightening things up would close these kinds of gaps. Are there any other short term fixes? I would really like to hold off doing this until I get some other things out of the way.

The manifold bolts on the 216 don't usually sieze too bad, since the heads are cast iron. The few that I have removed came off pretty easily.

Tightening the bolts probably will not help. The long castings warp easily under repeated heat/cooling cycles. The good news is that you can unbolt the intake and exhaust manifold as a pair and have a machine shop resurface them to flat as a unit. It should cost about $50 in most places.

I'd tell you that I have never broken a manifold bolt off in a head, but I don't want to jinx you.

Cheap solution, it works most of the time. First, be sure you have the intake rings, they slide into the head and manifold and help keep things aligned. Also a new set of gaskets and a tube of ultra-copper rtv. Remove the manifold set and clean the mating surfaces. I then put a bead of rtv on the mating surfaces of the manifold and install with the new gaskets. The rings can be stubborn, so have a little patience. If you need to, you can put some rtv on them to hold them in place. Tighten down the manifold bolts, but do not over tighten. I don't recall the torque specs, but they are low, and you can't get a torque wrench on most of the bolts. If you have pins in the end holes, they can be removed with vise grips and replaced with bolts. After tightening, inspect to be sure rtv has oozed out all the way around the ports. Then let then engine sit for a day allowing the rtv to cure. You can then trim off the excess with a razor or knife, and run the engine. In most cases this will solve your leak problem.