Exhausts are the lungs of your Navara and are made of multiple components. Starting from the manifold and all the way through to the tailpipe you'll find parts such as the oxygen sensor, catalytic converter, resonator and muffler. This is the usual set up which helps vent out gasses generated by the fuel combustion in the engine and also helps reduce the amount of harmful particles on the way out. These gasses enter the exhaust system through the manifold and then go to the oxygen sensor before passing through the catalytic converter, then they pass through the resonator, after that the muffler and at last they exit from the tailpipe.
Types of Exhaust Systems
Single Exit
Although all exhaust systems work the same there are still different types, each ideal for different vehicles. A single exit D40 Navara exhaust is usually found on models sold at dealerships. While these aren't the most efficient systems they provide solid performance whilst being the most affordable and easiest to install. The tailpipe of a single exit system is always on the passenger side.
Dual Side
This type of D40 exhaust vents out gasses more efficiently than a single exit system as it has two pipes next to each other on one side of the vehicle. They also sound and look like a high performance system, which we'll talk about in a bit, and they do offer some performance enhancements too.
Dual Rear
A dual rear D40 exhaust system is made for sportier vehicles or for those of you who want to make your Navara sound and look sportier. These Navara systems add a deeper tone to the exhaust which makes the engine sound more powerful. The two tailpipes on are positioned on opposite sides of the vehicle and do not bend as some other systems.
Opposite Dual
The system that does bend is opposite dual. These exhausts work in a bit of a different way as they wrap around the wheels. The bend helps with the filtering process which is why they are usually found on Navara's used to tow loads. The opposite dual system is a more efficient variant of the dual rear system but only when certain conditions are met.
High Performance
Unlike other exhaust systems a high performance exhaust is an aftermarket upgrade. But it does a pretty good job at filtering out the gasses and it can also help increase the vehicle's efficiency and engine performance. They are also more expensive than a standard exhaust upgrade.
Common Issues
Oxygen Sensor
Like any complicated system, an exhaust is also subject to a lot of issues and one of them has to do with the oxygen sensor. Although newer D40 Navara exhaust systems have multiple oxygen sensors, if one gets faulty the engine computer is not able to make a balanced mixture of fuel and air. This creates a mixture that is either low on fuel or air which may clog the catalytic converter.
Clogged Catalytic Converter
A clogged catalytic converter can prevent your Navara from reaching its normal power levels and the smell of a rotten egg will start to appear once it gets blocked.
Rust
Since exhaust systems are made of metal there is the risk of rust forming on the surface. The chances of this happening are especially high if you frequently take short trips. This causes water vapour to collect in the system since it doesn't have enough time to get hot enough and burn off the moisture. The condensation gradually turns to rust and starts corroding the exhaust from the inside.
Leak
Leaks can occur anywhere along the system which will make the steering wheel or gas pedal to vibrate. There will also be the smell of petrol and the risk of an accident.
Broken Hangers
Hangers are meant to keep the system from moving around when you hit a bump. A broken hanger can lead to dents and cracks in the system and at times even entire pieces to break off of it.
What You Can Do
Periodic Checks
The best way to look after your Navara D40 exhaust is to have it checked regularly by a professional. This will also help regulate the amount of emissions your vehicle is generating.
Engine Light & Rust
Another reason to bring your vehicle to the mechanic is the engine light. If you have it on it usually has something to do with emissions but there can also be an issue such as a faulty oxygen sensor or a catalytic converter gone bad. To prevent rust from forming try not to run errands one at a time, do multiple things at once so your vehicle stays warm so that water vapour gets burned off.
Connected Components
Taking a look of the underside of you Navara will not only help prevent leaks from becoming anything major but it will also help keep connected parts from sagging. Broken hangers can lead to that, so checking the undercarriage regularly will prevent greater issues.
