What Causes an Exhaust Manifold to Crack or Leak?

Your car has two manifolds – an intake manifold and an exhaust manifold. Both serve essential purposes, but the one most likely to experience problems over the long term is the exhaust manifold. Depending on your make and model, your manifold might be a single piece of cast iron with channels/ports built into it, or it could be a collection of pipes tied together. The basic job of the exhaust manifold is to take the gases from each cylinder and send them to the exhaust pipe.

Why manifolds crack and leak

As you can imagine, exhaust manifolds are subject to intense heat. They’re also subjected to considerable expansion and contraction as they heat up and cool back down. Over time, this leads to metal fatigue (both cast iron and other types of exhaust manifolds are subject to this). As the fatigue becomes worse, it’s possible for the manifold to develop cracks.

Another potential problem lies with the exhaust manifold gasket. The gasket sits between the manifold and the engine block, and is designed to seal the small gap that exists between these two components. Like the manifold itself, the gasket is subjected to significant heat, as well as expansion and contraction. It will eventually fail (this is normal, and cause by nothing more than general wear and tear). When it fails, it will begin to leak.

Problems associated with manifold cracks and leaks

There are several problems created with exhaust manifold cracks and leaks. First, hot exhaust gases are now being vented under the hood, rather than being sent downstream through the exhaust pipe. This can damage plastic components in the engine bay. It can also become a health hazard, as the exhaust fumes can enter the car’s cabin.

There’s also the possibility that it will affect engine performance. If your exhaust manifold is cracked or leaking, the back pressure in the exhaust system will be incorrect, which can reduce engine power, cause sputtering and other problems. Of course, you won’t pass emissions testing, either.


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Recent Exhaust Manifold Repair reviews

Excellent Rating

(158)

Rating Summary
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Brian

24 years of experience
200 reviews
Brian
24 years of experience
Hyundai Elantra L4-2.0L - Exhaust Manifold - Hanover, Pennsylvania
Brian informed me that there was an issue, other than the original situation, that would need work however, since it would require the vehicle to be on a lift, he would not be able to make that repair. He did however make the repairs that were originally requested.
GMC K1500 Suburban - Exhaust Manifold Repair - York Springs, Pennsylvania
Brian was absolutely the best most professional mechanic I ever hired. I would most definitely ask for his services again.

Duane

25 years of experience
510 reviews
Duane
25 years of experience
Jeep Grand Cherokee V8-5.7L - Exhaust Manifold - Oceanside, California
Duane showed up a few minutes early. As with the time before, when he did my scheduled maintenance, he was patient and courteous, answering any questions I had. Once he was done with the car he took time to answers more questions I had and set my mind at ease concerning my Jeep.

Shane

17 years of experience
217 reviews
Shane
17 years of experience
Hyundai Accent L4-1.6L - Exhaust Manifold - Hutto, Texas
Shane showed up early and promptly got to work. He finished the job in the allotted time. He helped save me hundreds of dollars. I really appreciate him.

Rashad

18 years of experience
53 reviews
Rashad
18 years of experience
Chevrolet Malibu L4-2.4L - Exhaust Manifold - Atlanta, Georgia
Rashad was great actually. He called me when he got the messages as well from his supervisor helping with the issue. We worked well making sure he has chance to start and finish the work on the car safely and well. It is nice and quiet for sure. Plus we saved some money too. Will use him again for the car for sure!!

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