Used Exhaust ManifoldUsed Exhaust Manifold

An exhaust manifold is essential for a properly functioning exhaust system. This part is designed to collect exhaust from the cylinder so that it can be delivered out through the exhaust pipes. In some cases, the exhaust manifold cracks or warps. Replacing the part with a used exhaust manifold is a simple project that is easy for most people to complete in an afternoon.

Exhaust Manifold Construction

The exhaust manifold varies based on the exact make and model of the vehicle, but the standard shape looks like several pipes that lead to a main pipe. The part is usually made from cast iron, but can also be made from stainless steel or steel alloy-type metals.

Identifying the Exhaust Manifold

The exhaust manifold looks like a collection of pipes that connect to the cylinder head. Most exhaust manifolds feature a central pipe with a smaller pipe on each side. These three pipes connect to the cylinder head. The number of pipes on the exhaust manifold can vary based on vehicle.

For example, some sports cars have up to six pipes on the exhaust manifold, and each pipe connects to the cylinder head. Manifolds that have more pipes than the standard three are typically made from stainless steel or another non-cast iron material. These types of exhaust manifolds are often found on high-performance vehicles.

Common Problems

Cracking is one of the most common problems associated with an exhaust manifold. The pipe may have a visible crack in it, or noises like hissing may occur when the vehicle is started. Sputtering or other power issues may also be present, or the heat generated by the released exhaust may cause damage to other parts in the engine.

For instance, the cylinder head may be damaged when the exhaust manifold is cracked, or plastic parts near the manifold may melt or warp. White burn marks may also be present on the manifold flange is the manifold is cracked. Replacing the exhaust manifold is essential if a crack is suspected.

DIY Replacement

Generally, the exhaust manifold is easy to replace. A used exhaust manifold is an option for a budget-friendly replacement. To replace the exhaust manifold, being by spraying an engine-safe lubricant onto the bolts holding the exhaust manifold in place. This step prevents rusted or corroded bolts from breaking during the removal process.

If necessary, tap the manifold lightly to remove it after taking the bolts out, and use a spanner or stud remover to remove broken studs. Check the cylinder head to ensure it isn’t warped before replacing the manifold by placing a straight edge along the connections. If the connections are warped, replace the cylinder head before setting the replacement manifold in place.

After removing the bolts, scrape the gaskets off the cylinder head. Set the new gaskets into place with the appropriate sealant, and set the replacement exhaust manifold in place. Starting with the center pipe on the replacement manifold, tighten the nuts to the recommended tightness using a torque wrench. The appropriate tightness settings are typically listed in the vehicle’s repair manual.