Is it safe to duct tape a damaged muffler?

No, duct tape is not a safe option for repairing damaged exhaust mufflers or exhaust pipes. Duct tape is made out of cotton mesh, and is covered with a type of plastic called polyethelyne, with a rubber-based adhesive underneath. When it gets hot, duct tape melts and becomes flammable.

It’s definitely not a good idea to repair your muffler of exhausts with this type of material. If your car is still under warranty, remember that any unauthorised repair work will void the warranty. Exhaust fumes are toxic, and a build up of them inside your car can be fatal, so it’s essential that your entire exhaust system is functioning properly.

If you need to make a temporary repair to a damaged exhaust pipe, you can fill the crack with a heat resistant sealant. An exhaust repair paste is a good choice and is sold at auto repair outlets. Clamp a tin can over it using metal hose clips. This should withstand the pressure and heat.

For safety and noise reasons, replace the damaged pipe as soon as possible. Remember, never work under your car using just a wheel jack, always use proper wheel ramps. Never have the engine running while you are underneath the car, and let the muffler and exhaust pipes cool down thoroughly before you touch them.