How to Remove Rusted Exhaust Manifold Bolts? Step by Step Guide

Rusted exhaust manifold bolts can be a hard thing to deal with. Your exhaust system is a significant safety hazard. And you’re going to need to get it fixed soon or else risk having your car emissions fail inspection. Not only that, leaks from the manifold will make your engine run poorly and put more pressure on other parts of the vehicle.

Suppose you have any idea how difficult these rusted bolts are to remove. Then you should consider reading this blog on how to remove rusted exhaust manifold bolts. So, keep reading & enlighten yourself.

remove rusted exhaust manifold bolts

What is an exhaust manifold bolt?

In your vehicle exhaust system, exhaust bolts hold various exhaust pipes to a car exhaust manifold. These exhaust manifolds are responsible for routing the exhaust from cylinders in the car engine. Also, to the rear of the vehicle or out through an exhaust pipe. The exhaust manifold is bolted onto a cylinder head and sends hot gas from engine cylinders into a collector, which routes the exhaust to the rear of the vehicle.

What could cause exhaust manifold bolts to rust?

Your exhaust bolts are at risk of getting rusted if they’re exposed to moist, humid conditions. If you live near the ocean, have your exhaust manifold checked for rust frequently. Saltwater is a big culprit when it comes to causing exhaust fasteners to rust and break off. Even rusted exhaust bolts made out of stainless steel are still at risk.

How to Remove Rusted Exhaust Manifold Bolts (Steps)

Removing exhaust manifold bolts isn’t an easy task. You need to follow specific steps to remove it.

Step 1: Make sure the engine is cool to touch

 Heat causes your exhaust manifold bolts to expand and break. So, make sure your engine becomes cool before you start this job. Also, allow yourself plenty of time since the process takes time to complete. Put on gloves and eye protection from injury during the job, especially if you’re working with wet, hot exhaust.

Step 2: Place a thick towel or something similar under the exhaust manifold

When you remove exhaust manifold, some exhaust bolts and nuts do fall off and could cause damage to your engine. Putting a thick towel or similar object under the manifold will ensure those bolts don’t hit your engine and cause more damage. It is also a good safety measure if they accidentally fall into the engine bay.

Step 3: Apply penetrating oil to loosen the rust

You can use a variety of penetrating oil from hardware stores to remove rusty screws or bolts. They all contain chemicals that dissolve rust and corrosion, making it easier for you to remove your fasteners.

Alternative process: Use a heat gun and a pry bar to remove the manifold

If you haven’t had any luck with penetrating oil, try using a heat gun or hair dryer to remove rusted bolts. Point the heat on each bolt and wait for about five minutes. If they still don’t budge, then use a metal pry bar.

Step 4: Use a ratchet or wrench to loosen the bolts

If you have a ratchet with an extension, use it to remove a rusted or broken exhaust manifold bolt. Otherwise, use a wrench to loosen the manifold bolts. You can also try penetrating oil for this job. The loosened bolts should come out quickly when you take them off in the next step.

Step 5: Take the bolts off the exhaust manifold

When you loosen all of your rusted bolts with a wrench or ratchet, they should quickly come off. If they don’t, try using penetrating oil again before deciding it’s time to move on to an alternative process. When taking them off, be sure to support the exhaust manifold with one hand. So, it doesn’t fall. Also, remove the bolts that connect the exhaust manifold to your engine head. You can follow the same technique for exhaust flange bolt removal.

What happens if you don’t remove rusted or broken screws & bolts?

If you remove all the bolts and leave some rusted ones behind, your car could catch on fire. When exhaust manifold bolts rust and corrode, they weaken and shrink. If they shrink enough, you may also face exhaust leak. The manifold can separate from your engine head. If you remove all of your rusted bolts and a few fall into the engine bay, remove them quickly.

Also, hot exhaust gases can shoot out due to obstructions of rusted and you can observe glowing red exhaust manifold .


1. How do I remove a stripped exhaust bolt?

If your exhaust bolt is stripped, you can try using a deep-well socket and an impact driver to remove it. You may need to use penetrating oil if the rust around the head of the screw or bolt has caused it to corrode.

2. How do you remove a rusted bolt without heat?

You can use a flat-head screwdriver or an air chisel with a drill. To do this, you will need the necessary tools to remove any rusted bolts without heat!

3. How do you remove a seized rusted bolt?

You can try using penetrating oil, heat, or an air chisel with a drill to remove it. After trying all other options, you may also want to use a hammer and punch if parts of the head are corroded.

4. How do you unscrew a rusted bolt without WD40?

If you don’t have WD40, try using a Phillips screwdriver and some elbow grease to get the job done.


It’s essential to know how to remove rusted exhaust manifold bolts for your car or truck to run efficiently. If you can’t get the bolt off, contact a mechanic who specializes in automotive repair. And let them take care of it. However, if they are removable, here is what you need to do:

You can use penetrating fluid, heat, or an air chisel with a heavy-duty drill. If you have the perfect tools and know what you’re doing. Then, any of these methods should work for your situation! We hope our guide has helped make things more straight forward! Contact us today for more information about automotive issues you might be having!


Mr. Rubel is an Engine Mechanic. He has more than 15 years’ experience on repair and maintenance of different kinds of vehicles. He is also providing training to mechanics and works as a Senior Mechanic of a well-known organization. He is sharing his knowledge to support the car lovers to solve the vehicle issues.

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