What are the Intake Manifold Gasket Leak Symptoms?

How Does an Intake Manifold Work?

The intake manifold uses pistons to conduct the air-fuel mixture and the coolant through the engine block via the valves to the relevant areas. It is important that these mixtures are distributed evenly, otherwise, the engine will not work as efficiently.


2. Coolant leaks

Another symptom of a faulty intake manifold gasket is coolant leaks. Some intake manifold gaskets also seal engine coolant, and if the gasket wears out it may lead to a coolant leak. This may produce a distinct coolant smell, along with steam, and drips or puddles of coolant underneath the vehicle. Coolant leaks should be addressed as soon as possible, in order to prevent them from becoming a greater issue.

4. Diagnosing Leaks With a Vacuum Gauge

Often, you can troubleshoot for a vacuum leak using a vacuum gauge, if the leak seems hard to find.

If you don't have a vacuum gauge, your local auto parts store may loan you one.

  1. Warm up the engine.
  2. Connect the gauge to a vacuum port on the intake manifold. The most common point is the vacuum hose that connects to the brake booster.
  3. Set your transmission to Park (automatic), or Neutral (manual).
  4. Engage the emergency brakes.
  5. Start and let the engine idle.
  6. In general, an engine in good mechanical condition will read between 17 and 21 inches of mercury (Hg) at sea level. Subtract 1 in-Hg from this range for every 1000 feet of altitude after the first 2000 ft. above sea level.
  7. If the needle on your gauge fluctuates between 3 and 9 in-Hg below the normal reading, most likely the intake manifold is leaking vacuum.

If you suspect a vacuum leak, make sure to check every vacuum hose. Vacuum hoses should be in good shape and properly connected. Another possibility is a cracked intake manifold. This can be a problem, especially on plastic intake manifolds.

If your vehicle comes with a two-part intake manifold, upper and lower, a leak can manifest in different ways:

  • A lower intake manifold with a leaking gasket can develop a vacuum leak, a coolant leak or an oil leak. If the manifold itself is cracked, it will develop a vacuum leak.
  • An upper intake manifold with a leaking issue, damaged gasket or cracked manifold, will develop a vacuum leak only.

Trouble codes stored in your computer's memory can help you diagnose the source of a vacuum leak

Photo in the Public Domain.

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.

Can K-Seal Fix My Intake Manifold?

If there is a coolant leak then, in most cases, using K-Seal, K-Seal HD and K-Seal Ultimate will help to quickly and permanently stop the leak, saving you a lot of time and money. Use our simple stockist search facility to find a bottle and get back on the road.

Intake Manifold Gasket Location

Your vehicle’s intake manifold gasket is located n

Your vehicle’s intake manifold gasket is located near your engine’s head between the intake manifold and the cylinder head. On V-shaped engines, it usually sits between both headers. For inline engines, it usually sits off to one of the sides.

Reaching your intake manifold usually isn’t too complicated, but there can be many electrical components sitting on top. Not only can this make it hard to access the intake manifold, but it can make it harder to see too.

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.

Intake Manifold Gasket Replacement Cost

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The intake manifold gasket is maybe the most expen

The intake manifold gasket is maybe the most expensive gaskets in a car due to its durability requirement and unique shape. A new replacement gasket will likely run you somewhere in the range of $50 to $120 which doesn’t sound so bad.

But the expensive portion will be the work required to replace it since it’s not easy to get to. The labor cost to replace an intake manifold gasket will set you back about $250 to $500. This number could even be higher for sports cars and luxury vehicles.

All together, on average you can expect to pay around $300 to $620 for the total cost of an intake manifold gasket replacement.

Read Also: Oil Pan Gasket Replacement Cost

How Much Does It Cost To Fix? Can’t I Do It Myself?

Unless you’re an experienced home mechanic with the proper tools and a safe place to work, it’s probably best to leave manifold work to the pros. The steps to remove, replace, and safely reconnect everything can be difficult to understand without experience, and the consequences of messing something up can be serious.

Having said that, it’s important to note that paying someone to fix an intake manifold won’t be cheap. On average, expected to pay between $400 and $600 for repairs. Most of that expense is related to labor, which can run upwards of $400 on its own.

5 Symptoms Of Bad Or Failing Intake Manifold Gaskets

The intake manifold gaskets are some of the most important gaskets found on an engine. Gaskets are the seals placed between engine components before they are assembled in order to provide a reliable seal. They can be made of paper, rubber, metal, and sometimes a combination of the three.

The intake manifold gaskets are responsible for sealing the intake manifold against the cylinder head(s). Apart from sealing engine vacuum, certain designs will also seal engine coolant. When the intake manifold gaskets have an issue, they can cause drivability problems and even engine overheating. Usually, a faulty intake manifold gasket will produce a few symptoms that can alert the driver of a potential issue.

1. Coolant leaks

Another symptom of a faulty intake manifold gasket is coolant leaks. Some intake manifold gaskets also seal engine coolant, and if the gasket wears out it may lead to a coolant leak. This may produce a distinct coolant smell, along with steam, and drips or puddles of coolant underneath the vehicle. Coolant leaks should be addressed as soon as possible, in order to prevent them from becoming a greater issue.

2. Engine Overheating

Engine overheating is another symptom of a possible issue with the intake manifold gaskets. A coolant leak will eventually lead to engine overheating when the coolant level drops too low, however, there are instances where overheating can occur without any visible leaks.

If the intake manifold gaskets leak coolant into the intake manifolds the engine may overheat as a result, without any visible external leaks. Any coolant leaks should be addressed as soon as possible to prevent the possibility of serious engine damage occurring due to a bad intake manifold gasket.

3. Engine Stalling

When the engine stops turning or is turning too slowly, then stalling will occur. This can happen when a faulty intake manifold gasket causes a vacuum leak, which messes up the ratio of air to fuel.

Then you could be driving and all of a sudden experience a stalled engine. Of course, there could be many other reasons for a stalling engine, but a bad intake manifold gasket is surely one of them. Go see a mechanic to have them verify if it is this gasket or not.

A mechanic will be able to perform a smoke test to rule out vacuum leaks. A smoke test injects smoke into the intake system. If there is a leak in the system, smoke will come out from an area it’s not supposed to.

4. Bad Fuel Economy

Since a faulty intake manifold gasket causes a disruption in the air to fuel ratio, then your engine is going to consume more fuel than normal.

This means you will be spending more money on gas for doing the same amount of driving that you normally do. As a result, your fuel economy will decrease greatly.

5. Loss of Acceleration

Aside from an engine stalling, you may notice a simple loss of acceleration after you step on the gas pedal. You may get a little bit of power at first, but then the acceleration will stop and start again as you keep your foot on the pedal.

You obviously shouldn’t continue to drive your vehicle when it is in this condition since it’s dangerous to do so. If you are experiencing two or more of the other symptoms, then you definitely need to have your intake manifold gasket replaced promptly.

Sometimes You Need a Certified Mechanic 

As much as The Drive loves to put the “you” in do-it-yourself, we know that not everyone has the proper tools, a safe workspace, the spare time, or the confidence to tackle major automotive repairs. Sometimes, you just need quality repair work performed by professionals you can trust like our partners, the certified mechanics at Goodyear Tire & Service.

Why Do Intake Manifolds Fail?

Intake manifolds fail because of the high levels of constantly-changing heat and pressure they are subjected to on a daily basis. The strain they are put under inevitably leads to cracks developing – it is up to the driver to diagnose the problem and deal with it at the earliest opportunity.

1. Intake Manifold Vacuum Hose Leaks

Perhaps, vacuum hose leaks are the most common leaks affecting an intake manifold.

  • You can inadvertently disconnect a vacuum hose while trying to service, repair, or replace an engine component.
  • It's not uncommon for vacuum hoses to degrade and start leaking after thousands of miles of operation under harsh conditions like pressure, high temperatures and oil spills.

To check for a leaking hose:

  • Find the under-hood vacuum hose diagram. It shows you the routing of hoses connected to vacuum-controlled components. If necessary, check your vehicle repair manual.
  • Visually check each vacuum hose.
  • Trace each hose with your fingers, feeling under the hose where your eyes can't reach. A hardened, rough or too soft a spot can be a sign of a failed or leaking hose.
  • Make sure each end of the hose is properly connected. You may need a telescopic mirror for hard-to-reach places.

Also, you can spray a suspect area on a hose with soapy water. If you see bubbles forming around the spot, you have found the leak.

You can also use starting fluid. When you spray the fluid on a leaking area, you'll notice the rough idle smoothing out as the engine burns the fluid in the combustion chamber.

An intake manifold gasket can develop external or internal leaks.

Author's own photo.

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