What is the exhaust manifold gasket?
The exhaust manifold collects the post-combustion gases from multiple cylinders and routes them into the exhaust pipe. The manifold is attached to the cylinder head, and the unit is sealed with the use of a exhaust manifold gasket. The design of the manifold and the seal provided by the gasket assist in exhaust scavenging, where gas exiting from the cylinder leaves a vacuum which pulls in more of the air/gas mixture. Extreme temperatures, oil, coolant contamination, and the constant barrage of exhaust gas will wear the gasket to the point where leaks will develop between the cylinder head and manifold.
What does the exhaust manifold gasket really do?
In simplest terms, it helps the engine breathe.
The engine is just a giant air pump, and the better the pump works at sucking in air and sending it out, the better our car drives. Usually we will notice a spitting type of sound from the engine compartment, especially when the engine works hard under a heavier acceleration or climbing up a hill. When leaks develop between the engine and the exhaust manifold, we would think that the engine would breath better. Not the case as these un-engineered leaks reduce the velocity of the exhaust stream. So we lose power.
How severe is exhaust manifold gasket replacement?
While this issue will not leave you broken down waiting for a tow truck, the repair may take some time. These leaks are most common on vehicles with advanced age. Rust sets in on all the bolts and nuts that hold down the manifold. They take time to undo, and in many cases break. It's best to find a good mechanic who specializes in exhaust, and set an appointment when the vehicle can be dropped off for several days.
What is the cost to replace the exhaust manifold gasket?
- Estimated part(s) cost = $50-$100
- Estimated labor cost = $300-500
Parts for this repair, regardless of the make and model, will not cost much. A new gasket and hardware (nuts and bolts) will run between $50 and $100, much of the price dependent upon the size of the motor. Labor time is the real expense in this repair. On many cars the manifold is buried within the engine compartment, then there is the fight to take off all the rusty nuts and bolts. You may be looking at $300 to $500 for the repair, and in some cases maybe more.
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Service article written by an ASE Master Technician