After years of extreme engine temperatures, removing exhaust manifold studs can be a near impossible task. Rust and corrosion can also fuse the exhaust manifold studs to the engine block of your older vehicle. Whether it’s to replace the manifold itself or to get at other parts inside your engine, off the bolts must come. When your exhaust manifold studs are stuck, try these tricks to get them off.
Step 1 - Hammer Time
Sometimes all your exhaust manifold studs need are a little bit of coaxing. A couple of firm taps with a hammer may be all it takes. The jolt from the hammer should be enough to break the seal that rust has created between the bolts and the engine block. Be careful not to hit the exhaust manifold studs too hard, as you don’t want to bend or break them.
Step 2 - Leverage
It’s the simplest idea that works most often with stuck bolts — use a cheater bar. Adding a length of iron pipe to your wrench or ratchet will give you the leverage you need for an extra bit of torque. The longer the handle on your wrench, the more torque you will have; making it easier to loosen the studs. Once the exhaust manifold bolt begins to move, be careful that the pipe doesn’t slip off the end of your wrench, damaging other parts of your engine.
Step 3 - Silicon Lubricant
An industrial strength penetrating lubricant spray will work wonders at loosening bolts that have been seized by rust and corrosion. Use a directional nozzle or straw to ensure the lubricant gets in between the exhaust manifold stud and the engine block, careful not to get any on the bolt head. Let the penetrating lubricant sit over night for the best results.
Step 4 - Block Heating
If you can’t loosen the bolt inside the engine block, then loosen the engine block around the bolt. Use a hand held torch to get the engine block around the exhaust manifold stud as hot as possible. The stud casing will expand with the heat, giving a little wiggle room for the bolt. You will have to work quickly before the heat transfers from the engine block to the bolt. This process also takes a bit longer, as you will need to let the engine block cool before repeating the process for the next bolt.
Step 5 - Fire and Ice
A faster option to the block heating method is to heat the exhaust manifold bolt itself and then cool it quickly. To do this, use your torch on the bolt head, getting the stud as hot as possible without changing its shape. Next, use a pair of tongs to hold an ice cube on the heated bolt (there will be hissing, steam and spluttering). Once the first ice cube has melted, hold a second ice cube to the bolt for one minute. The drastic change in the exhaust manifold bolt’s temperature and its quick change in size will break the seal that rust has made between the bolt and the engine block.
Removing your exhaust manifold stud wasn't too hard with this how-to. Enjoy your handy work!