7 Bad Intake Manifold Gasket Symptoms & Replacement Cost

bad intake manifold gasket

Some features of your vehicle don’t make sense whenever you think about them; you’ve heard that extra air is better for horsepower, and the cold air intake, additional scoops, and vents, among other things, are excellent ways to boost efficiency.

All of this is undoubtedly accurate, but let’s take a step back and discuss a leaking or faulty intake manifold. Although additional air is typically beneficial, it’s crucial to note that uncontrolled air pouring into your engine could quickly constitute a significant issue.

Excess air into your engine, which your vehicle’s computer doesn’t understand where it came from and what to do with it, causes significant air/fuel ratio problems, which, you know, gives your automobile its oomph.

As a result, a leaking intake manifold is a terrible thing. Failure of this component can wreak havoc on your ride’s cooling system, leading to stalling or catastrophe. What exactly is an intake manifold? What is the significance of this? Let us impart some information to you. Read on to learn more!

Bad Intake Manifold Gasket Symptoms

  • Engine Misfires
  • Engine Overheating
  • Engine Stalling
  • Bad Fuel Economy
  • Poor Acceleration
  • Coolant Leaks
  • White Smoke

What Is An Intake Manifold?

An intake manifold is responsible for delivering air to your engine cylinders. In conjunction with your air intake, fuel delivery system, and throttle body, the manifold assists in the supply of the proper air/fuel mixture for engine combustion.

The runners and the plenum are the two primary components of the intake manifold. Its plenum serves as a storage area for air till it is required in the cylinders. The air is carried through the plenum to the cylinder head by its runners.

What Is An Intake Manifold Gasket?

Since the purpose of your intake manifold is to route the proper fluids, gases, and engine requirements to their appropriate locations throughout your vehicle’s engine, this routing process is aided by its intake manifold gaskets. This gasket seals off any possible exit points for such fluids and gases.

Intake manifold gasket functions by sealing over each of your intake manifold’s channels, maintaining everything in its proper place. It may not appear to be challenging, and it isn’t, yet it doesn’t make it less significant.

Symptoms of A Bad Intake Manifold Gasket

Fuel is used in automotive engines. The correct fuel/air mixture is what makes your engine run properly. Once this feed is interrupted, the engine suffers, and its performance degrades. Below is a list of symptoms to look out for. Your engine will be saved from severe damage if they are detected early.

Engine Overheating

An overheating engine aggravates the issue of coolant leakage. When a faulty intake manifold gasket has indeed caused an internal coolant leak, coolant will flow through your intake manifold.

Your engine will ultimately overheat if this occurs. On its surface, you might not see any apparent leaks flowing off your car. However, when your engine starts overheating, it’ll display on your dashboard.

It’s essential to deal with this problem asap. When left untreated, an overheated engine is sure to inflict severe further damage. If you have an overheating engine, ensure you’re replacing the proper component by ruling out other sections of its cooling system.

A leak test would reveal if the head gasket is blown or the cylinder head has cracks. You might also do a check on your thermostat to make sure it’s in good functioning order. Overheating may also be caused by a thermostat that’s jammed closed.

Engine Stalling

Stalling occurs whenever the engine ceases spinning or starts spinning too slow. This could occur if a damaged intake manifold gasket creates a vacuum leak, causing the air/fuel ratio to be messed up.

Then there’s the possibility that your engine would suddenly stall while you’re driving. There are various causes for engine stalling, but a leaky intake manifold gasket is undoubtedly among them. Consult a mechanic to discover whether the intake manifold gasket causes the problem.

To clear out vacuum leaks, your mechanic would conduct a smoke test. Smoke is injected through your intake system during a smoke test. Once there’s a leak in your system, the smoke will escape into places it shouldn’t.

Decreased Engine Performance and Misfires

Your leaking intake manifold gasket allows air to exit while allowing coolant to enter. Each of these factors might have a detrimental impact on engine performance. It’s unlikely that you won’t be able to drive your car or that it would shut down when you’re going, but you may notice a decrease in acceleration and fuel efficiency.

The main concern in such a situation is that when your coolant blends with your engine oil, not only will your coolant lose its efficiency, but your oil will also be unable to take action properly.

This might result in increased wear and tear on a variety of components, as well as costly damages. When you use a scanner to examine the trouble codes, you could uncover misfire fault codes in your ECU (engine control unit.) Once your intake leak is severe, it might fill your cylinders with coolant, causing the engine to hydrolock, making it hard to start.

This is a highly hazardous situation that might cause significant harm to your vehicle. Fortunately, this is a rare occurrence since most automobile engines are engineered to allow coolant to flow straight into your intake manifold.

Poor Fuel Economy

As a result of the interruption in the air/fuel ratio caused by intake manifold leaks, your engine will burn extra fuel than usual. This implies that you would waste extra money on fuel for the same driving quality that you typically do. As a consequence, your fuel efficiency will be significantly reduced.

Poor Acceleration

Even though the issue hasn’t progressed to the level of creating misfires, a leaking intake manifold gasket makes it very challenging for your automobile to accelerate. The air seeping out of your intake manifold causes substantial power loss. It reduces the quantity of air that reaches your engine and causes a vacuum leak across your whole air intake system.

Regardless of how large your throttle body opens, any vacuum leak decreases air pressure in your engine—as a result, pushing the gas pedal is frequently unable to provide the desired acceleration. Instead, your automobile seems to move at a constant, slow pace.

Coolant Leaks

Your intake manifold gasket, as previously stated, guards from more than only air leakage; it also serves to seal engine coolant. Coolant can leak out the system whenever the intake manifold gaskets are compromised.

Even a tiny leak will ultimately lead coolant levels to decrease to dangerously low levels. Watch out for any symptoms that your vehicle has a coolant leak. Keep an eye out for any coolant spots in your driveway or your garage.

Since these symptoms might be caused by several issues with your cooling system, one of them could be a blown intake manifold gasket. Every automobile owner should see the indicators of a faulty intake manifold gasket. Those who do not will likely face even more severe issues.

White Smoke

You can’t tell what’s happening within your intake manifold until you disassemble your engine. Still, at that moment, whether your intake manifold gaskets are failing or not, you must replace them.

That’s why it’s critical to understand how to diagnose this issue without dismantling anything. The simplest method is to run your engine and examine your exhaust because your engine is consuming coolant whenever there’s a lot of white smoke streaming out of your exhaust.

Coolant leaking can only enter the combustion chamber by a failing head gasket or intake manifold gasket leak — in either case, you’ve got a problem. When assessing if the quantity of white smoke is overwhelming, always remember that you’ll produce more smoke in the winter than you would in the summer, which is perfectly natural.

What Causes The Intake Manifold Gasket To Go Bad?

Once your intake manifold gasket is broken, it might leak, causing a range of issues with your car. Coolant will penetrate the engine when your intake manifold gasket produces a leakage, perhaps causing irreversible damage if not addressed promptly. Below are the factors that can cause your intake manifold gasket to fail.


Intake manifold gaskets aren’t built to last together with your vehicle. Your intake manifold gasket could likely wear out from periods of usage and exposure to hot engine fluids if your car is older or has a significant mileage.

Because of their structure or low-quality aftermarket gaskets, specific engines are more vulnerable to intake manifold gasket breakdown. Intake manifold gaskets made of plastic are particularly prone to fail throughout time.

Vacuum Leaks

Coolant leaks are more prevalent than vacuum leaks produced by a leaking intake manifold gasket. On the other hand, your intake manifold gasket might be damaged, leading to excessive or insufficient air reaching your intake manifold and combining it with fuel. As a consequence, your car will perform poorly.


Heat is among the leading reasons behind intake manifold gasket degradation. When your engine overheats, its cylinder heads expand. Its gasket would be fractured when the metal expands and no longer create an appropriate seal.

When your car has overheated significantly or continues to overheat often, or coolant levels persist in dropping, and you can’t locate the source of the leakage. You should inspect your engine oil to ensure that coolant is not seeping into your engine oil.

Intake Manifold Gasket Replacement Cost

If your automobile suffers from one or more of the symptoms above, you will almost certainly need to replace your intake manifold gasket rather than merely repair it. There’s no more convenient than having a mechanic inspect your vehicle for you. And you’ll almost certainly need to replace this component before it becomes too late.

Your intake manifold gasket might cost anywhere between $50 up to $300 based on the automobile brand, year, and size. While the cost of your intake manifold gasket might vary significantly, the pricing of the mechanic’s effort to remove, replace, and install it can also fluctuate based on the same parameters. Your mechanic might charge you anywhere from $150 up to $550 plus a service fee.

Simply changing your intake manifold gasket might cost anything from $200 up to $700. While it isn’t the cheapest task, it may be among the most expensive if it isn’t fixed promptly. Burned engines and associated problems are significantly more costly than a straightforward gasket replacement, so have this fixed as soon as possible.

Can You Drive With A Bad Intake Manifold Gasket?

While driving with a leaky intake manifold gasket is generally doable, you must not go too long. These problems don’t disappear on their own, yet they don’t become better over time either.

Leaking more unmetered air entering your combustion chamber might cause the automobile to run lean, meaning your engine would probably run hotter. Knock or pre-detonation is also more common. A pretty fine engine might be ruined by excessive knock under load.

An overheated engine is more prone to suffer further damage, such as a warped or fractured head or a broken block. Repairing this damage will be significantly more expensive than just replacing your intake manifold gasket.


It would be better if you weren’t worried by one of the mentioned symptoms of a bad intake manifold gasket anymore since you already know them. As long as you have adequate expertise, getting rid of this issue would be a piece of cake once you detect the problem and determine the cause. Otherwise, don’t delay contacting a skilled mechanic to avoid further damage to your vehicle.

Based on the design and position of your intake manifold as it’s located in your engine, every vehicle would have a somewhat different technique of replacing a faulty gasket. As a result, we recommend obtaining a copy of your vehicle handbook to locate your car’s gasket seal.


What does a bad intake manifold sound like?

It’s a piercing hissing noise that sounds like you’re air going in through your teeth since that’s precisely what’s going on.  It isn’t a pressure leak; it’s a sucking air noise created by your piston sinking on its intake stroke, making a fractional vacuum pressure in your intake manifold.

How serious is an intake manifold leak?

A leaky intake manifold allows air to escape while allowing coolant to enter. If your intake leak is severe, it might flood your cylinder with coolant, causing your engine to hydrolock, making it hard to start. This is a highly hazardous situation that might cause significant harm to your vehicle.

Related Posts

Leave a comment