The exhaust manifold is a shared component across all TD and TF engines, collecting exhaust gases from the cylinder head and directing them into the front pipe. The manifold-to-head mounting hardware is also shared with the inlet manifold, creating an interconnected assembly where both manifolds must be addressed together during any gasket replacement.
The Manifold Assembly
The cast iron exhaust manifold is a single casting that serves all four cylinders, bolted to the exhaust side of the cylinder head. It shares its mounting hardware with the inlet manifold: four studs thread into the cylinder head, carrying four clamps and four nuts that hold both manifolds simultaneously against a single shared gasket. The manifold studs, clamps, nuts, and the shared gasket are common across all TD and TF specifications. Because the gasket is one piece covering the mating faces of both manifolds, exhaust manifold removal inevitably disturbs the inlet manifold seal, and the gasket should always be renewed when either manifold is removed, not reused.
Manifold-to-Downpipe Connection
The three-stud flange connecting the manifold to the exhaust front pipe uses brass nuts specifically to resist heat-induced seizure. Ordinary steel nuts will corrode and weld themselves to the studs over years of heat cycling, making future removal extremely difficult, brass resists this effect. The manifold-to-downpipe gasket seals this connection and should be renewed at every removal. The studs themselves are subject to heat cycling stress and should be inspected for stretching and thread condition when the joint is disturbed; a cracked or broken stud will cause an exhaust blow at the flange joint, and extraction of a broken stud from the cast iron manifold requires careful specialist work to avoid cracking the manifold itself.
Manifold Condition Assessment
Cast iron exhaust manifolds are not immune to cracking after decades of thermal cycling. Hairline cracks typically develop between the exhaust ports and may not be visible externally until the manifold is cleaned and inspected closely. A cracked manifold will cause an exhaust blow audible as a ticking noise from the engine bay, most noticeable at idle and under light load. Cracks can sometimes be repaired by specialist welding, but replacement is the more reliable long-term solution for a manifold that has cracked significantly.
When assessing a manifold's condition, check for warpage of the head mating face as well as cracks, a warped manifold will not seal cleanly against the head and will cause persistent exhaust leaks regardless of the gasket specification fitted.
Ordering Considerations
The exhaust manifold itself, its mounting hardware, and its gaskets are common across the TD and TF. When ordering manifold-related parts, the single shared manifold-to-head gasket should always be renewed together, it is not a separate inlet gasket or exhaust gasket but one combined component. Brass nuts should always be used at the manifold-to-downpipe flange; steel replacements will create a seizure problem at the next removal. The manifold-to-downpipe gasket should be renewed at every disassembly, regardless of the gasket's apparent condition.