Six Signs of a Bad Intake (and Replacement Cost)

For perfect combustion, the intake manifold controls the exact distribution of air to the engine cylinders.

Your car's engine performance is directly affected by the intake manifold.

Unfortunately, the intake manifold fails sometimes – but what happens if it does, and how much will it cost to get it fixed?

This article will cover the common signs and cost of fixing or replacing a bad intake funnel. Let’s go take a look at the signs first!

Six Bad and Cracked Signs of Intake Disorder

The most common sign of a cracked or bad intake manifold is a check engine light on your car’s dashboard. Other issues may occur with your engine's performance.

An unhealthy or cracked intake can be characterized by the following symptoms:

This is a detailed listing of symptoms that indicate a damaged or bad intake system:

Make sure your engine light is on

The engine control unit is constantly monitoring your car’s sensors while you are driving it, and if any of them is sending wrong values compared to the pre-set values – the check engine light will appear on your dashboard.

A bad intake manifold will cause your air-fuel mixture to change, and the check engine lamp will appear on your dashboard.

When the check engine light shows up – there is also a trouble code stored in the engine control unit that you need to read to continue the troubleshooting.

Failures

If the coolant leaks or cracks in the intake manifolds, this will cause more air to enter the combustion chamber than fuel. This will result in misfires – which happens when the combustion process got disturbed and not completed.

Coolant water can build up in the cylinder from coolant leakage around or in the intake gasket. Misfires can also be caused by a problem code found in the engine control panel.

Read more about 5 Signs That Your Intake Manifold Gasket Is Not Working

Rough Idle

You may already know that a damaged or cracked intake manifold can cause bad air-fuel mixture. Bad air-fuel mixtures can cause an idle to go rogue.

Because the engine needs to be running perfectly in order to maintain a constant RPM, it is more susceptible to issues at idle. At idle, you'll most likely notice an issue with your intake manifold.

Performance loss

The fuel/air ratio can be affected if the intake manifold is damaged. We all know how important the air-fuel mixture is for efficient combustion, so any effect on this mixture can affect your car’s fuel consumption.

The engine will consume more fuel. You'll need to top up the tank much more often. Additionally, you may feel your car not acceleration properly and the engine might be having hiccups.

You should inspect your intake manifold to make sure there are no leaks.

External coolant leaks

Coolant could leak from the engine bay when there is an issue near the intake gasket or internal crack in the intake manifold.

You should check your intake manifold for signs of leaks if you notice coolant in the car's underside after spending the night in garage.

It is common for the leak to be located underneath the intake manifold.

Engine Overheating

If the intake manifold has a crack and causes the coolant to pour out in the engine bay or into the combustion chamber, the engine’s first effect starts to overheat due to the loss of coolant.

This will occur while you drive. If the temperature gauge on your dashboard rises, it's a sign that the engine is overheated.

The best way to detect this is to check the coolant level in the engine bay regularly, and if you notice that it has slowly started to decrease – it is time to check for coolant leaks.

Find out more about the overheating of your car engine here.

Function of the intake manifold

The purpose of the intake manifold is to deliver an even amount of air into the car engine’s cylinders.

Older cars had the carburetor inject fuel prior to the intake manifold. For these engines the intake manifold was required to distribute the fuel equally.

Modern cars use fuel injectors to inject fuel into the intake manifold. This is a more efficient way of injecting fuel.

Modern cars have swirl flaps in them. This creates an efficient engine that produces a smoother air flow when it enters the combustion chamber.

You can take in many locations

On one side of an engine, the intake manifold can be found on the cylinder heads. The intake manifold for V-engines is situated in the middle of the cylinder heads.

It is easy to see the intake manifold in car engines as it is usually located in high-up in the engine bay.

To see the part in some cars you will need to take off some of the plastic covers. You will often find them made out of metal or plastic. To spot one, look at the image above.

If you know how many cylinders your car has – look for a part with the same amount of pipes as your car’s cylinders.

Take Manifold Replacement Price

The cost of replacing an intake manifold is typically $300 to $1100 depending on car make and labor costs. A manifold can cost $200 to $600 while labor is $100 to $500.

The cost of your car will vary depending on its engine, make and model. This will also depend on whether you're looking for OEM parts or aftermarket ones.

You will pay a lot more for the intake manifold than you would like. It is a large piece of metal, so not much can go wrong with it.

However, there are some intake manifolds that have intake flaps. This means you will need to replace the entire intake system.

If you are able to learn basic skills and can do the job yourself, replacing an intake manifold usually takes about 1-2 hours. Some intake manifolds have flaps that need to be programmed after an intake manifold replacement – especially European cars.

FAQs about the Intake Manifold