Exhaust Repairs

Engine exhaust is highly dangerous. It is hot, smelly, and deadly. When your vehicle has an exhaust leak or problem, it is critical to get it repaired as soon as possible. In this article, we will examine common exhaust system problems and how to do an emergency repair yourself for about $9.

How Hot is Hot

Internal combustions engines, as their name implies, create explosions to power vehicles. These explosions, of course, are very hot. How hot? Some temperatures around the exhaust manifold in extreme conditions can reach 1200 degrees F. This is uncommon, but it shows how hot things can get. However, the average external temperature of many exhaust parts is around 400 to 450 degrees F. This is pretty darn hot.

Anyone working on exhaust parts needs to be extremely careful to let the system cool down before beginning any repair.

Exhaust Gases

We all know that exhaust gas is usually smelly and dangerous. But what is it made of? Exhaust gases, if you have a catalytic converter, basically consist of nitrogen, oxygen, carbon dioxide, and water. The work of the catalytic converter is to convert gases such as nitrogen oxide, carbon monoxide, and hydrocarbons into much safer gases as I mentioned above.


Perhaps one of the greatest dangers of the exhaust system is leaking gases. If the catalytic converter is cracked or broken, it is possible for deadly carbon monoxide to flow into the interior of the car. Or, if the car is in an enclosed space, carbon monoxide can enter the enclosed space.

According to the Centers for Disease Control and Prevention (CDC.gov), during the span of 2010 to 2015, a total of 2,244 deaths resulted from unintentional carbon monoxide poisoning. Of course, this is the total number, not just the deaths from car exhaust related accidents. Nonetheless, carbon monoxide is a real danger.

Quick Repair

It is always best to have a professional mechanic make any exhaust repairs. However, you may need to temporarily repair a hole or break in an exhaust system component yourself. That is why I carry a stick of J-B Weld in my toolbox.

J-B Weld and other manufacturers offer a kind of high-temperature putty or paste for quick, temporary repairs. You can use the standard J-B Weld stick for some muffler repairs, as long as it states this on the packaging. Better yet, J-B Weld offers HighHeat™, an epoxy putty stick that can withstand 450 degrees F of continuous heat, and intermittent heat of 500 F. For even greater heat protection, they offer J-B Weld 37901 ExtremeHeat™ metallic paste that withstands up to 2400 degrees F. Pretty amazing.

I have not used the ExtremeHeat™ version of J-B Weld myself, but I have read about people using it on cracks in exhaust manifolds. Amazing, if you ask me.

If you are using the J-B Weld (or another manufacturer) putty stick, be sure to follow the directions exactly as written. Also, definitely wear protective gloves. This stuff gets sticky and makes your hands smell terrible.


Exhausts that are leaking or broken need to be fixed as soon as possible. The dangers of carbon monoxide and high heat are great. You can use J-B Weld HighHeat™ for quick repairs, but make sure you get the exhaust repaired properly.

Written by Gary Pradel