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Sti spoiler broken bolt extractor11/29/2023 Miraculously, we were able to get a pair of vise-grip pliers on the nut and hold it tight enough to remove the manifold collector bolts. All of the exhaust manifold bolts came out without issue, but the collector nuts that had rotted away were a problem. We were able to pull the heat shield free and then remove the studs on the ground without hurting anything. Normally, you can't just spin the studs out with the heat shield in place, but in our case one of the seized stud nuts was on one of the snapped studs and the other loosened just enough before refusing to budge that it created enough slack to allow the stud to spin out without destroying the heat shield. Furthermore, two of the nuts that held the heat shield on had seized to the studs and wouldn't spin. All of our bolts came out in one piece, but two of our studs had snapped. In our case, the Hemi exhaust manifolds use four studs and five bolts. Also, the exhaust manifolds can expand and contract unevenly, which could cause the cast iron to crack, compounding the incorrect O2 sensor readings, not to mention making the annoying exhaust leak sound worse. If the O2 sensor thinks the engine is running leaner than it should, it will trigger more fuel to be dumped into the engine, potentially causing harm to the catalytic converter(s). With only part of the manifold cinched tightly to the engine cylinder head, the exhaust gasket will blow out, not only allowing exhaust gases to escape, but possibly allowing air to enter the exhaust stream, throwing off the O2 sensor's readings. Eventually it's gonna come apart in your hands. It's not too dissimilar from bending a paper clip back and forth. After hundreds of expansion and contraction cycles, the studs or bolts finally fail. That rapid heat causes the exhaust manifold material to expand, which puts a tremendous strain on the bolts and/or studs holding the manifolds to the cylinder heads. Under extreme use like towing heavy loads, the exhaust manifolds can go from normal operating temperature to cherry red in a matter of seconds. Once the vehicle was driven a short distance, the manifolds swelled up and the tick was mitigated, but we figured we'd highlight the fix before it got too severe. Most recently at 262,000 miles the passenger side started the telltale "tick, tick tick" when the engine was cold. Furthermore, the broken studs were only in finger-tight, so we were able to just spin them out and replace the gasket and bolts with little drama. We got really lucky and those particular studs snapped off with about 1-inch of exposed stud shaft sticking out of the cylinder head. Then, at about 188,000 miles the driver-side exhaust studs snapped. The passenger and driver exhaust manifold bolts let go at roughly 70,000 miles and we had them replaced by the dealership under warranty. In addition to regular commuting duties we frequently use the little workhorse SUV to tow a 6,500-pound wakeboard boat or a Jeep/trailer combo of similar weight. We have a 2004 Dodge Durango with the aluminum-head 5.7L Hemi that we purchased brand new. If you use a gasoline-powered V-8 pickup or SUV to tow a trailer, chances are you're going to eventually have an exhaust leak caused by broken manifold bolts or studs.
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