How to Fix a Rattling Heat Shield

When your car is running smooth and quiet, we assume that everything is fine with the overall health of the vehicle. Usually, loose parts indicate that something needs attention and the safety and reliability of the vehicle may be compromised. A rattling exhaust heat shield may be seen as only annoyance though for some people it can be embarrassing too. In some instances, a loose exhaust shield can be a major issue requiring immediate attention by a competent mechanic.

Since the exhaust is primarily responsible for pushing out extremely hot gases away from the vehicle’s engine, all components around the exhaust manifold, catalytic converter, muffler and exhaust pipe get very hot. More particularly, the catalytic converters are significantly hot since they start functioning only when the temperature reaches 400 degrees Fahrenheit and beyond and can reach up to about 1,600 degrees Fahrenheit. Conversely, the temperature around the rest of your car’s exhaust system pegs around 500 degrees Fahrenheit.

Rattling exhaust heat shield

Many components in your car cannot manage excessive heat. Rubber and plastic parts can become brittle or simply melt away while sensors and electric motors can fail and paper or dry grass can combust spontaneously. The exhaust shield is created from thin sheets of metal and the exhaust heat shield deflects most of the excessive heat and some of these shields are fixed to the exhaust system itself while others are fixed to parts of your engine needing protection.

Vibration and heat are among the major causes of exhaust heat shield failure.  The very parts that the exhaust shield is designed to keep protected are surprisingly the common cause leading to failure. Metals are susceptible to corrosion, particularly when they are exposed to the elements in the atmosphere and heat hastens the process. Consequently, bolts, clamps or welds can rust and defeat the purpose for which they are there and you can have a loose exhaust shield. Vibrations contribute to further weakening of the metal and this can lead to the exhaust shield falling off or rattling against the exhaust system and other components of your vehicle.

Fixing the rattling exhaust shield

A rattling heat shield may be seen as an unwanted element in the vehicle by some car owners and they simply choose to remove and discard them. But, this can lead to more complex problems since the exhaust shield is designed for the protection of other parts in the car from the heat emitted by the exhaust and removing the exhaust shield wholly can cause fire or premature failure of many components. Therefore, the best solution for a rattling exhaust shield is refixing it or replacing it.

Fixing the rattling exhaust shield:

Welding is an option to fix the rattling exhaust shield. You will need to either find a welder who can accomplish this task or take your vehicle to a garage.  An experienced welder can take the exhaust shield to the exhaust pipe. But this job should be done with extreme care since the thin metal on the pipe and the exhaust shield can burn through.

Bolts: In some instances, it may be possible to overcome the problem by installing new bolts and nuts to a bolt-on type heat shield. It is quite likely that you find the holes to be too large for the new bolts but this problem can be overcome with the use of fender washers to cover the additional space.

Clamp: In certain situations, SS screw camps can come to your aid if the exhaust shield was clamped or welded to the exhaust pipe.

Tie: Yet another method to fix the loose exhaust shield is using an SS tie which will be free from rust post-installation. For larger components, link multiple components like muffler heat shield together.

Common causes of exhaust heat shield rattling

Following are among common causes of exhaust heat shield rattling:-

Excess heat emanating from Engine Bay

A significant amount of heat is generated by modern-day engines even during regular use. The exhaust manifold generates most heat from a majority of engines and the metal pipe employed for exhaust gases to escape the engine. But, a heat shield is employed to prevent excessive heat from causing damage to components beneath the hood so that the high temperature is contained. Extreme heat around the engine bay is among the early symptoms of a damaged heat shield. When the heat shield is lost or damaged, it fails to provide the required protection and the heat soaks the engine bay. You will notice that the vehicle is warmer than usual at the front end and more so with the hood opened. In some instances, the hood can also become extremely hot when you touch since all the excess heat is absorbed by the hood.

Burning smell

Another symptom of damaged or failed exhaust shield is burning smell. When the exhaust shield fails in protecting the vehicle’s engine from exhaust heat, the components in the vicinity can easily suffer damages. With heat reaching sensitive or plastic components, the parts can burn up due to excessive heat. This can trigger a burning smell and even smoke in some cases, apart from causing damages to the parts affected.

Rattling noise

Another symptom of a failed exhaust shield is rattling noise coming from the vehicle’s engine bay.  This can be due to rust damage or poor hardware and can cause vibration leading to the rattling sound. At lower speeds, the sound tends to be more prominent and pitch of the sound may change at higher speeds. To overcome the problem, your vehicle will need a professional inspection.

Conclusion

The exhaust shield coming as original equipment with most of the modern vehicles are designed to last the lifecycle of the vehicle. Therefore, before heading to a mechanic or garage, check the vehicle’s warranty terms and ensure that you are headed in the right direction for the required attention.