Symptoms of Intake Manifold Gasket Leaks

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Ah, good old Manifest Destiny, giving every American the right to expand and spread over our noble land, in search of their own slice of the American dream.

Er… what I mean of course is that the manifold gasket is a very important part of the vehicle engine. Yes, this is a car site, not a history one.

But as important as the intake manifold is, one of the first questions many people have is:

Symptoms of Intake Manifold Gasket Leaks

What is the Intake Manifold?

That is a fair enough question actually, since the intake manifold plays a very important role in the engine, but it is not a component that everyone is familiar with. That is mainly because whilst its gaskets can fail from time to time, the intake manifold itself is pretty long lasting.

The intake manifold is basically a large multi-chambered component. It is connected to the air filter at one end and the engine cylinders at the other. The job of the intake manifold is to deliver the air and fuel mixture into the cylinders that the engine needs to operate.

It’s not much of an understatement then to say that the intake manifold performs quite an important job. In this article though we’re not here to talk about the intake manifold itself (we’re real teases, huh?) but instead to take a look at the intake manifold gaskets.

In particular how you can tell when they have gone bad and need replacing.

What are Intake Manifold Gaskets?

Huh? Oh yeah, before we get to the next stage we better just cover what exactly the intake manifold gasket actually is.

There are actually a number of gaskets in the engine of your vehicle. They can be made from a number of materials like paper, rubber and metal – and sometimes even a combination of two or more of those materials.

You’ll find them everywhere that a seal is required in the engine. In other words where two components meet, you’ll find a gasket helping them to bond and work together.

As we mentioned above, the intake manifold is a component that connects to the engine cylinders. It is in that connection there that you will find the intake manifold gasket itself.

Why is it a Big Deal When this Gasket Goes?

It is possible to make a case for the intake manifold gasket being the most important gasket in the engine. That is because it provides a seal at the point where the gasoline and air mixture the engine runs on is being inserted into the engine.

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Gas is like food for the engine, whilst the air it is mixed with is like the blood in your veins. The gas is suspended in the air so it can move to where it is needed. When the intake manifold gasket is not running properly, that blood and energy supply is cut off.

It should go without saying that this is bad news for your car, and will have a huge impact on performance.

A secondary factor to consider is the fact that the intake manifold gasket also helps to keep coolant in the engine block. So again, when it is failing it can start to rain coolant under your car and coolant on the asphalt is not doing much to keep your engine temperature under control.

In fact, spoiler alert, it is doing nothing.

How to Tell When the Gasket is Bad

There are five tell tale symptoms of a blown gasket, or at least a gasket that is not long for this world:

  • Acceleration Loss

Because of the role the intake manifest plays with the engine, when the gasket is not working properly one of the big giveaways can be the fact that acceleration will suffer.

This is because, as we discussed above, the intake manifold is responsible for injecting the air and fuel mix into the engine cylinders. If you recall, we described this by using a very cool food and blood metaphor, remember?

Well, to take that metaphor a little further, imagine that you are running and getting more and more out of breath. The more you struggle to breathe, the harder it is to maintain a quick running pace, right?

(Also how about putting the hot dog down and getting off the couch every now and then, huh?)

The same applies to your engine. When it struggles to get enough air and fuel (because the gasket is allowing both to leak) it will struggle to perform, as you would expect.

  • Bad Fuel Economy

Have you noticed that you’ve been visiting the gas station more frequently? It could be because you’re driving miles out of your way every time the Krispy Kreme hot light comes on.

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Or it could be a faulty gasket seal. As we mentioned above, the gasket plays a key part during the injection of the air/fuel mix. When the gasket is not dong it’s job, the air/fuel ratio is going to be wrong.

That in turn leads to extra fuel bills for you. Which, on top of all the money you spend on doughnuts, is going to start denting your bank balance.

  • Coolant Leak  

This next symptom may not be seen in every vehicle, however some engines use the intake manifold gasket to also seal in engine coolant liquid. If your car is one of those models that do this, the symptoms of coolant leakage are pretty easy to spot.

The first big indicator is going to be the rather distinct smell of burning coolant that is going to enter the cabin after short periods of driving. Basically any journey that is long enough for the engine to heat up properly is going to be accompanied by a not very nice smell.

You could also get the visual indicator of pooling coolant that is gathering underneath the vehicle when it has been parked up for a while.

  • Engine Overheating

This next symptom is very much continuing on from the one above. In fact, if you don’t catch a coolant leak via the smell or the physical signs of a leak itself, then you definitely won’t miss a big engine heat warning light on your dashboard display – at least we hope you won’t.

The leaking coolant, and the engine overheating that this can lead to, is one of the worst symptoms of a damaged gasket. A car or truck engine that is constantly running too hot can lead to major damage occurring like a cracked head gasket or warped cylinders.

That is some serious engine damage we are talking about there, with a repair price tag well above that for a simple gasket replacement.

In our minds then (or what passes for our minds), symptoms 4 and 5 are kind of the most important on the list. Yes, if you spot the others then definitely get your gasket looked at.

  • Engine Stalling
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Finally, you may notice that your car stalls a lot more often when the intake manifold gasket has failed. This is largely connected to symptoms 1 and 2, where the gasket is affecting the air/fuel ratio that is reaching the engine cylinders.

This is a tougher symptom to attach to a failed gasket though, as there are actually quite a few reasons why an engine may stall. If it presents with one of the other symptoms, then definitely check out your manifold intake gasket.

But if you spot the signs of coolant leakage and/or your engine warning light is going off, then you must investigate that as a matter or priority.

Sorry, we won’t nag you again like that in the rest of the article, we promise!

Replace an Intake Manifold Gasket

If you have noticed that your vehicle is displaying one or more of the above symptoms, then the next step is going to be a gasket replacement.

A mechanic can replace an intake manifold gasket for a few hundred bucks including parts and labor.

It is one of the more complicated engine repairs, but could be within the remit of an experienced and well equipped at home mechanic.

Each vehicle will have a slightly different method of replacing a damaged gasket, depending on the design and location of the intake manifold gasket as it is found in your vehicle. We would therefore suggest getting hold of your vehicle manual for reference to the location of the gasket seal in your car.


A bust gasket seal can have serious implications for the performance of your car. It can lower mileage, it can make the car harder to drive and in the worst circumstances it can even lead to serious engine damage occurring over the long term.

Fortunately, it is relatively easy to know when the gasket needs replacing, especially if you keep an eye out for the five symptoms we talked out above. If you happen to notice any of them in the course of your driving, get your car to a mechanic for a check up (or get under the hood yourself if you know what you’re doing!)

Good luck and happy driving, guys!

Originally posted 2023-12-28 22:50:07.

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