• engine

What is an exhaust manifold and what does it do?

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Updated 11 Oct 2019

Fionna Blackburne

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An exhaust manifold is a cast iron or stainless-steel assembly which gathers engine exhaust gases from the engine cylinders and delivers it to the exhaust pipe.

How do I know if I have a manifold problem?

Due to the intense heat, exhaust manifolds are subjected to considerable expansion and contraction as they heat up and cool down and over time this may cause the exhaust manifold to crack and leak.

Signs the exhaust manifold is damaged:

  1. Loud noise coming from the engine.
  2. Lack of engine performance.
  3. Poor fuel economy.
  4. Engine light on – related to the emissions system.
  5. Toxic gases coming from the engine bay.

It’s important to note that toxic gases are a health and safety concern.

Exhaust gases escaping from the engine can also be a fire hazard, melting nearby plastic components in the engine bay.

Can a manifold be repaired, or does it have to be replaced?

Small leaks and cracks on the exhaust manifold can be welded shut or patched.

However, large cracks will require more extensive repair. Note that this is still considered a temporary fix.

Upon inspection of the manifold, if the leak or crack is considered too severe, the structural integrity of the unit is compromised.

It is in these circumstances that the exhaust manifold should be replaced by a qualified technician.

What’s the cost?

A new exhaust manifold will set you back somewhere between $350 - $2,000 depending greatly on the make and model of your vehicle.

The costly part of this job is the exhaust manifold itself which will come with a 12 or 24-month warranty.

Looking after your exhaust system isn’t hard, but it does involve you paying attention to your vehicle and being proactive when issues arise.

Need a quote on your exhaust manifold repair or replacement?

No worries. Use AutoGuru to get quick, fixed price quotes from local service providers.

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Written By

Fionna Blackburne

Fionna is the owner of Southeast Auto Mechanical in Beenleigh, Queensland. A former lawyer, Fionna decided on a radical career change, qualified as a light vehicle mechanic and took over Southeast Auto in 2016.

As well as delivering quality service to their customers, Fionna and her team run an award-winning, free car maintenance workshop program for women.