Removing the intake manifold on a Nissan Almera G15: instructions with photos and tips

Removing the intake manifold Nissan Almera G15 - a task that sooner or later faces every owner who decides to repair the engine, replace gaskets or clean the throttle valve. The procedure requires accuracy and knowledge of key nuances, especially if you are doing it for the first time. Unlike newer models Nissan, where the design may differ, intake manifold G15 has its own characteristics: a cramped engine compartment, fragile plastic pipes and the risk of damage to sensors if handled carelessly.

In this article we will walk you through the process of removing the manifold step by step - from preparing tools to final assembly. You will learn which fasteners most often “stick”, how to properly disconnect electrical connectors so as not to break the chips, and why you can’t ignore checking the condition of the gasket after dismantling. The material will be useful to both beginners and experienced car owners who want to avoid common mistakes.

Preparing for work: tools and safety precautions

Before you begin removing the intake manifold, make sure you have everything you need. You will have to work in cramped conditions, so quality of instruments plays a key role. Here is the minimum set that you cannot do without:

• 🔧 A set of sockets and a ratchet wrench (necessarily with an extension and a cardan for hard-to-reach bolts).
• 🔨 Screwdrivers: Phillips (PH2) and flat (for removing clamps and prying up plastic clips).
• 🧰 Pliers with narrow jaws (for removing spring clamps on pipes).
• 🔥 WD-40 or a similar composition for treating “stuck” threaded connections.
• 📦 Marker or stickers for marking connectors and pipes (this will save hours when reassembling!).
• 🧴 Sealant for gaskets (for example, Loctite 574 or ABRO 11-AB) - in case the old gasket requires replacement.

Preparing the car is no less important. Nissan Almera G15 does not have a spacious engine compartment, therefore:

• 🚗 Place the car on a level surface and secure the handbrake. If possible, use a lift or inspection hole - this will make it easier to access the lower manifold mounts.
• ⚡ Disconnect the negative terminal of the battery to avoid short circuit when working with electrical connectors.
• 🔥 Let the engine cool down (working on a hot engine is dangerous - risk of burns and deformation of plastic parts).

⚠️ Attention: On models Almera G15 with engine HR15DE pay special attention to the absolute pressure sensor (MAP-sensor). Its connector often breaks when removed carelessly - the chip is fragile, and a new sensor costs from 3,000 rubles.

Removing the air filter and throttle assembly

The first stage is to free access to the collector. On Nissan Almera G15 this starts with removing the air filter housing and throttle body. Here's the step-by-step sequence:

1. Unscrew the 4 bolts securing the air filter housing cover (10 mm socket). Remove the cover and remove the filter element. If the filter is dirty, it is better to replace it - this will eliminate the need for repeated dismantling in the near future.

2. Disconnect the air duct corrugation from the throttle assembly. It is secured with a spring clamp - pry it up with pliers and slide it along the corrugation. Be careful: plastic pipes on Almera G15 become fragile over time!

3. Unscrew the 2 bolts securing the throttle assembly to the manifold (12 mm socket). Before doing this, disconnect the throttle position sensor connector (TPS) - the chip is fixed with a plastic clip, which must be carefully bent.

After removing the throttle body, you will have access to the top of the intake manifold. It is important to take your time here: dirt and oil deposits often accumulate under the throttle. Clean the surface using carb cleaner or gasoline to prevent debris from getting into the intake channels during further disassembly.

Negative battery terminal disconnected |

Air filter housing removed|

Air duct corrugation disconnected|

TPS sensor connector disconnected|

The surface under the throttle assembly has been cleaned -->

Disconnecting electrical connectors and vacuum hoses

One of the most critical stages is working with electrical and vacuum lines. On Nissan Almera G15 Several key connectors and hoses connect to the intake manifold:

element	Location	Disconnection Features
Absolute pressure sensor (MAP-sensor)	Upper part of the collector, closer to the windshield	A chip with a plastic clip - press it and pull it up. Don't pull the wires!
Intake air temperature sensor (IAT)	Built into the duct corrugation or filter housing	It often gets stuck - gently rock the connector from side to side.
Brake booster vacuum hose	The lower part of the manifold, closer to the partition of the engine compartment	Remove the clamp and pull the hose away from the nipple. If the hose is cracked, replace it.
Crankcase ventilation hose (PCV)	Rear of manifold, next to valve cover	Often clogged with deposits - check the passage after removal.

When disconnecting connectors, pay attention to their markings. On Almera G15 Manufacturers often use the same chips for different sensors - it’s easy to confuse them. Mark with a marker or take a photo of the location of each connector.

⚠️ Attention: If you remove the manifold for cleaning, do not use wire brushes or abrasives to clean the internal passages. Micro scratches will disrupt laminar air flow, which will lead to uneven engine idling.

Removing the intake manifold: step-by-step instructions

Now let's move on to the collector itself. On Nissan Almera G15 it is attached to the cylinder head with 6 bolts (sometimes 8, depending on the year of manufacture). Here's how to remove it correctly:

1. Treat all threaded connections WD-40 or similar composition. Allow the liquid to soak for 10–15 minutes - this will make it easier to unscrew the “stuck” bolts.

2. Unscrew the manifold mounting bolts in the sequence “from the edges to the center”. This will help avoid flange deformation. Use a 12mm socket with an extension - access to the bottom bolts is limited.

3. After removing the last bolt, carefully lift the manifold up. It may "fit" tightly due to an old gasket. Do not use excessive force - it is better to pry the manifold around the perimeter with a flat-head screwdriver.

4. Make sure all pipes and connectors are disconnected. People often forget about the canister hose or the canister purge valve connector (Purge Valve).

After removing the manifold, carefully inspect it for cracks, especially in the places where the throttle assembly and vacuum fittings are attached. Plastic collectors on Almera G15 Over time, they can develop microcracks, which lead to air leaks and unstable engine operation.

What to do if the manifold mounting bolt breaks?

If a bolt breaks off while unscrewing, don't panic. In most cases, it can be drilled out, but there are some nuances:

1. Use a drill with a diameter 0.5–1 mm smaller than the bolt diameter.

2. Before drilling, apply a drop of oil to the broken area - this will reduce the heating of the metal.

3. After drilling, tap a new thread or screw in a bolt with threadlocker (for example, Loctite 243).

4. If the bolt is seated in an aluminum cylinder head, be careful - too much force when drilling can damage the threads in the cylinder head.

Assessing the condition of the gasket and preparing for reassembly

After removing the manifold, first inspect the gasket. On Nissan Almera G15 it is most often made of multilayer cardboard with metal reinforcement. Signs that the gasket needs to be replaced:

• 🔍 Visible cracks or tears along the edges.
• 🛢️ Traces of oil or antifreeze on the surface (indicates a violation of tightness).
• 🔥 Burnt edges (indicates overheating and loss of elasticity).
• 📏 Deformation - if the gasket “went in waves”, it will not provide a tight fit.

If the gasket is in good condition, it can be reused, but be sure to clean both mating surfaces (manifold and cylinder head) from the remains of old sealant and carbon deposits. A plastic scraper or soft brush is suitable for this. Do not use sandpaper under any circumstances - it leaves risks that will subsequently lead to air leaks.

Before installing the new gasket, apply a thin layer of sealant to both sides. This guarantees tightness even with microdeformations. For Almera G15 The following compositions are suitable:

• Loctite 574 — high temperature, can withstand up to +300°C.
• ABRO 11-AB - a budget option, but requires a thicker layer.
• Permatex Ultra Black — optimal for plastic manifolds.

⚠️ Attention: When installing the manifold, do not tighten the bolts by eye. Tightening torque for Nissan Almera G15 amounts to 20–25 Nm. Exceeding this value will lead to deformation of the flange or breakage of the threads in the aluminum cylinder head.

Installing the manifold and checking for leaks

Assembly is carried out in the reverse order, but there are several critical points:

1. Install a new gasket on the cylinder head, aligning all holes. Make sure it lies flat and without distortion.

2. Carefully lower the manifold into place, being careful not to dislodge the gasket. Start with the top fasteners, then secure the bottom bolts.

3. Tighten the bolts in 2-3 increments, starting from the center and working outward. This will ensure an even fit.

4. Connect all connectors and hoses according to the marks made during disassembly. Check that none of the pipes are kinked or strained.

After assembly, it is necessary to check the tightness of the system. To do this:

1. Connect the negative terminal of the battery and start the engine.

2. Check for air leaks - for this you can use a smoke generator or simply listen to the engine at idle. A characteristic hiss will indicate the location of the leak.

3. Inspect the junction of the manifold and cylinder head for oil leaks or escaping air.

If the engine is unstable, check:

• 🔌 Correct connection of all electrical connectors (especially MAP-sensor And TPS).
• 🔄 Tightness of vacuum hoses (you can blow them with compressed air).
• 📊 Presence of errors in the ECU (for example, P0105 — malfunction of the absolute pressure sensor circuit).

Common mistakes and how to avoid them

Even experienced craftsmen sometimes make mistakes when working with the intake manifold. Nissan Almera G15. Here are the most common ones and ways to prevent them:

Error	Consequences	How to avoid
Using wire brushes to clean the commutator	Micro scratches → disruption of laminar flow → uneven engine operation	Use plastic scrapers or special cleaners (eg Liqui Moly Pro-Line Drosselklappen-Reiniger)
Tightening the manifold bolts without a torque wrench	Flange deformation or thread breakage in cylinder head	Observe the tightening torque 20–25 Nm
Ignoring gasket check	Air leaks → increased fuel consumption, unstable idle	Always inspect the gasket for cracks or deformation.
Mixed up vacuum hoses	Incorrect operation of the brake booster or crankcase ventilation system	Mark the hoses during disassembly or photograph the connection diagram

Another typical problem is damage to plastic pipes when removed. On Almera G15 they become fragile after 100,000 km. If the pipe is cracked, do not try to repair it - replace it with a new one. Silicone analogues (for example, from Silicone Intakes) last longer and withstand higher temperatures.

Frequently asked questions (FAQ)

Is it possible to remove the intake manifold on an Almera G15 without removing the throttle body?

Technically it is possible, but it will significantly complicate the process. The throttle assembly blocks access to the upper manifold bolts, and without removing it you will have to work “blindly”, risking stripping the threads or damaging the pipes. We recommend removing the throttle - this will take no more than 10 minutes.

What sealant is best to use for manifold gasket?

For Nissan Almera G15 High-temperature silicone-based sealants or anaerobic compounds are optimal. Best options:

• Loctite 574 — does not leak, withstands up to +300°C, suitable for aluminum surfaces.
• Permatex Ultra Black — does not contain solvents, does not damage oxygen sensors.
• ABRO 11-AB - budget-friendly, but requires a thicker layer and polymerization time (1-2 hours).

Avoid cheap acrylic-based sealants - they quickly tan and crumble.

What should I do if, after assembly, the engine stalls or is unstable?

There may be several reasons:

1. Air leakage through the gasket or loose bolts. Check the tightening torque (20–25 Nm) and inspect the joint for cracks.
2. Incorrectly connected sensor connectors (MAP-sensor, TPS). Refer to photographs taken during disassembly.
3. Clogged throttle valve or intake ducts. Clean them with carb cleaner.
4. Errors in the ECU. Connect the diagnostic scanner and reset the adaptations.

If the problem persists, check the compression in the cylinders - the cylinder head gasket may have been damaged when removing the manifold.

Do I need to change the manifold gasket every time I remove it?

Not required, but recommended. Gasket on Almera G15 wears out over time, especially if the manifold has been removed more than once. Signs that it is time to replace the gasket:

• Visible cracks or tears.
• Traces of oil or antifreeze on the surface.
• Burnt edges (indicates overheating).
• Deformation (if the gasket “went in waves”).

If the gasket is externally in order, it can be reused, but with the obligatory application of sealant.

How long does it take to remove and install the manifold?

Time depends on experience and condition of fastenings:

• For a beginner: 4–6 hours (including cleaning, checking the gasket and possible difficulties with “stuck” bolts).
• For an experienced mechanic: 2–3 hours.

Disconnecting electrical connectors and vacuum hoses usually takes the longest - there are many of them, and they are often located in inconvenient places.