Exhaust system <em>Nissan Murano Z51</em>: device, diagnostics and modernization

Nissan Murano Z51 is a crossover that combines dynamics and comfort, but even in such a reliable car the exhaust system requires attention. The exhaust here not only affects sound and environmental friendliness, but is also directly related to engine performance VQ35DE (3.5 l) or QR25DE (2.5 l). Owners are often faced with corrosion of mufflers, errors in oxygen sensors, or a desire to improve the sound - and in each case an individual approach is needed.

In this article we will analyze exhaust system design Murano Z51 (2008–2014), typical breakdowns and their symptoms, as well as tuning options - from budget resonators to premium systems Borla or MagnaFlow. We will place special emphasis on unique feature of this model: the sensitivity of the ECU to changes in back pressure in the exhaust, which can lead to an error P0420 even with working catalysts.

Exhaust system design Nissan Murano Z51: circuit and components

Exhaust Murano Z51 consists of several key nodes, each of which performs its own function:

• 🔥 Exhaust manifold - cast from cast iron (on VQ35DE) or stainless steel (on QR25DE), is connected to the cylinder head through a gasket. Installed on the collector oxygen sensors (lambda probes).
• 🌀 Catalytic converter - integrated into the exhaust pipe (on models for the USA and Europe) or made as a separate unit (for markets with less stringent standards).
• 🔊 Resonator and muffler — the basic configuration uses stamped steel parts with internal perforations to absorb noise.
• 📏 Exhaust pipes — diameter varies from 50 mm (before the catalyst) to 63 mm (rear part of the system).

Feature Murano Z51 — dual exhaust (two pipes on each side), which gives the car a sporty look, but complicates repairs. For example, replacing a rear muffler requires removing the heat shield and sometimes even partially disassembling the suspension. By the way, on models with all-wheel drive (4WD) the exhaust system has additional fastenings to the frame to protect against vibrations.

Why does the P0420 code often appear on the Murano Z51?

Error P0420 ("Low catalyst efficiency") on Murano Z51 may appear not only due to wear of the catalyst, but also due to:

1) Air leaks into the system (for example, through a crack in the exhaust pipe).

2) Malfunction of the second lambda probe (after the catalyst).

3) Using non-original sensors with incorrect calibration.

4) Installation of "spiders" (4-2-1 or 4-1) without flashing the ECU - this changes the gas flow parameters, and the control unit records “abnormal” operation.

Component	Material	Service life (thousand km)	Typical faults
Exhaust manifold	Cast iron / stainless steel	150–200	Cracks, gasket burnout
Catalyst	Ceramic monolith	100–150	Hammering, melting of honeycombs
Rear muffler	Aluminum coated steel	60–80	Corrosion, rotting of welds
Corrugation	Stainless steel	80–100	Rupture, loss of elasticity

Typical exhaust problems Murano Z51 and their symptoms

Owners Murano Z51 Most often they encounter the following problems:

⚠️ Attention: If after starting the engine you hear metallic knock in the exhaust system area, turn off the vehicle immediately! This could be a sign that the muffler's internal baffles have become detached, resulting in a complete blockage of gas flow.

• 🔊 Increased noise - often caused by a rotten resonator or a crack in the exhaust pipe. On Murano with a mileage of more than 120 thousand km this is a major problem due to corrosion.
• 🚨 Errors P0420/P0430 - indicate a malfunction of the catalyst or lambda probes. On VQ35DE The error can appear even with a working catalyst due to air leaks.
• 💨 Exhaust smell in the cabin - usually associated with damage to the corrugation or manifold gasket. Especially noticeable when driving at low speeds.
• ⚡ Power Loss — if the exhaust “chokes” the engine (for example, a clogged catalyst), Murano will stall when accelerating above 3000 rpm.

The problem can be diagnosed by characteristic signs:

• 🔍 Visual inspection — rust, traces of soot around the joints, wet spots (condensation or antifreeze if the cylinder head gasket is broken).
• 🎧 Audition - knocking, whistling (air leaks) or popping noises (ignition malfunction, fuel mixture).
• 📊 Diagnostics with a scanner — errors on lambda probes (P0130–P0167) or catalyst (P0420/P0430).

Exhaust system diagnostics: step-by-step instructions

To accurately determine the cause of the malfunction, follow this algorithm:

1. Check ECU errors - connect the scanner (for example, Launch CReader) and write down the codes. Errors P0420/P0430 require checking the catalyst, and P0130–P0167 — lambda probes.
2. Inspect the system on a lift - pay attention to:
   • Integrity of welds (especially in places where corrugations are attached).
   • Condition of rubber hangers - they should not be torn or stretched.
   • Presence of soot at the joints (a sign of air leaks).
3. Check back pressure - for this you need:
   • Disconnect the first lambda probe (before the catalyst).
   • Connect the pressure gauge to the hole.
   • Start the engine and increase the speed to 3000 rpm. Normal pressure - no more 0.3 kgf/cm².

Disconnect the negative battery terminal|Jack the car or use a inspection hole|Clean any dirt from the exhaust system (especially around the sensors)|Prepare WD-40 for stuck nuts|Have new gaskets on hand (eg. Nissan 14045-4M000 for collector)

-->

If you find crack in the manifold, do not try to brew it - on Murano Z51 This is a temporary solution due to high temperatures. The best option is to replace it with a new or used manifold with a mileage of up to 100 thousand km. For VQ35DE suitable collectors from Nissan 350Z (article 14040-AL500), but the fasteners will need to be modified.

Replacing exhaust components: what to choose and how to save

When choosing spare parts for Murano Z51 important to consider:

• 🔧 Original parts - the most expensive, but guaranteed to fit in geometry and materials. For example, rear muffler Nissan 20560-4M000 costs ~25,000 rubles, but will last 80–100 thousand km.
• 💰 Analogues — brands Walker, Bosal or Eberspächer offer high-quality alternatives for 60–80% of the price of the original. For example, the exhaust pipe Walker 21946 will cost ~12,000 rubles.
• 🔨 Universal parts - suitable for budget repairs, but welding will be required. For example, corrugation HJS 100.30.5000 (diameter 50 mm) costs ~1,500 rubles.

When replacing the catalyst, owners Murano Z51 often face a dilemma: to install the original (~40,000 rubles) or universal catalyst (~15,000 rub.) with modification. Important nuance: on models with VQ35DE after 2010, the ECU is sensitive to the volume of the catalyst - if you install too small, it will light up Check Engine.

Detail	Original (item)	Analogue (brand)	Price (RUB)
Front pipe with catalyst	Nissan 20500-4M000	Walker 21946	35 000 / 12 000
Rear muffler	Nissan 20560-4M000	Bosal 994-100	25 000 / 8 000
Corrugation	Nissan 20525-4M000	HJS 100.30.5000	5 000 / 1 500
Lambda probe (front)	Nissan 22690-4M000	Denso DOX-0103	8 000 / 3 500

⚠️ Attention: When replacing lambda probes with Murano Z51 Never use universal sensors with crimp terminals! They do not provide tightness, and after 10–15 thousand km air will begin to leak, which will lead to an error P0130.

Exhaust tuning: how to improve sound and power

Exhaust system upgrade Murano Z51 has two goals: sound improvement (more sporty tone) and power increase (by reducing back pressure). However, it is important to remember: VQ35DE Illiterate tuning can lead to ECU errors.

Popular options:

• 🔥 "Spider" 4-2-1 — replaces the standard manifold, improves gas removal at high speeds. Suitable for naturally aspirated engines. Example: HKS Hi-Power (article HKS 80008-AN003).
• 🌀 Direct flow muffler — replaces the rear can, gives a bass sound. Popular models MagnaFlow (series MF Series) or Borla (Borla 140533).
• 📉 Removing the catalyst + blende - a cheap way to increase power by 5-7 hp, but requires installation lambda probe emulator (For example, GOFAST GF-007).
• 🎵 Valve system - allows you to switch between quiet and sport modes (for example, Remus with electronic control).

On Murano Z51 with VQ35DE The best option for daily use is to replace the rear muffler with Magniflow (For example, MagnaFlow 14289) + installation medium length resonator. This will give a nice bassy sound without the drone in the cabin and will not cause ECU errors.

Common mistakes when repairing and tuning exhaust

Even experienced technicians sometimes make mistakes that lead to repeated breakdowns or ECU errors. That's what can't do on Murano Z51:

• 🛠️ Use sealant instead of gaskets - high temperature sealants (for example, Abro) burn out over time, and the joints begin to leak gases.
• 🔥 Cook aluminum parts with argon without flux - this leads to microcracks that appear after 5–10 thousand km.
• 📉 Installing "dummies" instead of a catalyst without cheating - on Murano Z51 The ECU detects the absence of a catalyst based on the parameters of the second lambda probe.
• 💨 Ignore interior ventilation — after welding the exhaust, be sure to check the operation of the air recirculation valve (Nissan 27270-4M000).

Another common mistake is incorrect tightening of fasteners. On Murano Z51 The manifold nuts must be tightened in strict sequence to the torque 40–50 Nm (use a torque wrench!). If you overtighten, the manifold may become deformed, which will lead to air leaks.

Exhaust System Maintenance: How to Extend Service Life

To exhaust Murano Z51 lasted longer, follow these recommendations:

• 🚿 Clean your exhaust system in winter - salt and reagents destroy the metal. Use anti-corrosion sprays (For example, Liqui Moly 3930) at joints and welds.
• 🛢️ Monitor the condition of the engine - a rich fuel mixture (due to faulty injectors or mass air flow sensor) leads to overheating of the catalyst.
• 🔧 Check the fastenings — every 20 thousand km, tighten the clamps and replace the rubber suspensions (part number Nissan 20530-4M000).
• 📊 Diagnose lambda probes — their resource is ~100 thousand km. If there are signs of wear (slow response, errors P0130–P0167) replace with a pair.

If you often drive off-road, install exhaust system protection (for example, from Addictive Desert Designs). It will prevent damage when hitting obstacles. It is also useful to treat the muffler ceramic coating (For example, Thermal Cerakote) - this will reduce thermal loads and extend the service life of the metal.

FAQ: Frequently asked questions about exhaust Nissan Murano Z51

Is it possible to remove the catalyst on a Murano Z51 without consequences?

Technically yes, but you will need:

1. Install lambda probe decoy (mechanical or electronic).
2. Disable the second oxygen sensor programmatically (if the ECU is sensitive to its signal).
3. Be prepared for an increase in fuel consumption by 0.5–1 l/100 km and possible problems with passing inspection.

On VQ35DE after 2010, removing the catalyst often leads to an error P0420, even with deception. In this case, only flashing the ECU will help.

Which muffler is best for quiet sound?

For Murano Z51 will fit:

• MagnaFlow series MF Series — mufflers with direct flow, but with good absorption of high frequencies.
• Borla Touring — optimized for a comfortable ride, the sound is 20–30% quieter than stock.
• Walker Quiet-Flow - a budget option (~6,000 rubles), but lasts no more than 50 thousand km.

If you need completely silent option, consider installing an additional resonator (for example, Vibrant 1142).

Why does error P0130 not go away after replacing the lambda probe?

The reasons may be as follows:

• Poor quality sensor - buy only Denso or NGK (articles DOX-0103/NTK 25177).
• Air leaks in the system - check the manifold gasket and corrugation.
• Problems with wiring - oxidation of contacts in the sensor connector or breakage of the signal wire.
• ECU malfunction is rare, but occurs on Murano Z51 after 2012.

Before replacing the sensor necessarily check the voltage at its connector with the engine running (should be ~0.1–0.9 V).

How much does it cost to completely replace the exhaust system on a Murano Z51?

The cost depends on the choice of parts:

Option	Price (RUB)	Service life
Original (full set)	80 000–120 000	100–150 thousand km
Analogues (Walker/Bosal)	30 000–50 000	60–80 thousand km
Used (from disassembly, mileage up to 100 thousand km)	15 000–25 000	30–50 thousand km
Universal parts + welding	10 000–20 000	20–40 thousand km

The cost of service work is ~10,000–15,000 rubles. (including welding).

Is it possible to replace the corrugation on a Murano Z51 yourself?

Yes, this is one of the simplest operations. You will need:

• New corrugation (for example, HJS 100.30.5000).
• Grinder or hacksaw for metal.
• Welding machine (or clamps, if the corrugation is on the flanges).
• WD-40 to loosen the nuts.

Step by step instructions:

1. Disconnect the corrugation from the pipes (usually it is welded in two places).
2. Clean the weld areas from rust.
3. Weld the new corrugation, ensuring the alignment of the pipes.
4. Check the tightness (you can use a soap solution).

If there is no welding, you can use repair corrugation with clamps (For example, Walker 35035), but this is a temporary solution.