Valve cover on Nissan Almera Classic with engine MR18DE or MR20DE - this is not just a decorative element that hides the gas distribution mechanism. It performs the critical function of sealing the top cylinder heads, keeping engine oil inside the system and protecting internal components from external dirt and moisture. Over time, under the influence of high temperatures and vibrations, the gasket material loses its elastic properties, which leads to leaks.
Owners Nissan Almera Classic often encounter the problem of a characteristic whistle or noise coming from under the hood. In most cases, the source of sound is not the motor itself, but a deformed or incorrectly installed timing cover or valve cover. Ignoring this problem can lead to serious consequences: from an oil fire on a hot manifold to dirt getting into the engine, which can lead to costly repairs.
Design features and materials
Original valve cover on Nissan cars was made using high-quality heat-resistant plastic, which is able to withstand constant heating up to 120-140 degrees Celsius without deformation. The design includes special channels for ventilation of crankcase gases, which are connected to the system forced ventilation (PCV). A leak in this system leads to an increase in pressure inside the engine and squeezing out oil through weak points.
Particular attention should be paid to the gasket, which is made of a special composite material. Over time, it hardens and cracks, especially in places where it contacts the metal surface of the block head. Unlike many competitors, we have Nissan Almera the gasket is often attached to the cover itself, which simplifies replacement, but requires ideal surface cleanliness during installation. If you notice traces of oil on the side of the engine, it means the seal has already been compromised.
Some owners try to solve the problem with a cheap analogue, but cheap plastic quickly melts from the heat of the exhaust manifold. Original number parts usually begin with the prefix 13270, and replacing it with a low-quality duplicate often leads to repeated leakage after just a couple of months of operation. It is important to understand that saving on this part can result in a loss of time and money for repeated repairs.
⚠️ Caution: Do not try to use regular sealant instead of gasket on Nissan Almera Classic. High temperatures in the exhaust manifold area will destroy most standard sealants, turning them into a sticky mess that clogs the oil pan.
The main symptoms of a valve cover malfunction
A malfunction can be determined not only by external signs, but also by characteristic sounds. If you hear a metallic clicking or knocking noise that gets worse as engine speed increases, this is a sure sign that clearance in hydraulic compensators increased due to lack of oil or air entering the lubrication system. Most often this happens precisely when the valve cover seal is broken.
A visual inspection of the engine compartment often reveals oil leaks flowing down the cylinder block to the timing belt or generator. An oil film on belts causes them to slip and prematurely wear, which can lead to belt breakage and engine shutdown. Oil can also get into the spark plug wells, causing misfires and unstable engine idling.
- 🔊 The appearance of extraneous noise and knocking in the upper part of the engine, especially when cold.
- 🛢️ Traces of fresh or old oil on the side surface of the cylinder block and on attachment belts.
- 🕯️ Contamination of spark plug wells, which leads to spark discharge and engine tripping.
- 🌡️ The smell of burnt oil appears from under the hood when warming up or driving.
If these symptoms are ignored, oil will leak out in large quantities, reducing the level in the crankcase. A low oil level leads to oil starvation, overheating and scuffing in the cylinders. Diagnostics should be carried out immediately when the first signs are detected.
- Every day
- Once a week
- Once a month
- Only when the light comes on
Cover removal and diagnostic procedure
To carry out high-quality repairs, it is necessary to dismantle the valve cover, which requires a certain sequence of actions. First you need to remove the decorative engine cover by unscrewing the mounting bolts and disconnecting the sensor connectors. Then you need to disconnect the crankcase ventilation system pipes and the throttle cable, if it is mechanical. Be extremely careful not to damage the fragile plastic fittings.
Unscrewing the cover fastening bolts must be done in a strictly defined sequence, starting from the edges to the center, to avoid distortion. Use a torque wrench as plastic bolts or studs can be easily damaged if too much force is used. After removing the cover, carefully inspect the gasket: if it has cracks, burrs, or has lost elasticity, it must be replaced. Also check the cover itself for cracks, especially in the fastening area.
☑️ Preparing to remove the cover
Pay special attention to cleaning the seat on the cylinder head. Any remaining old gasket or sealant may cause another leak. Use a special carburetor cleaner and a plastic scraper to avoid damaging the metal surface. Purity - the key to reliable sealing. If there are deep scratches or signs of corrosion on the surface, they must be sanded.
⚠️ Attention: When dismantling the cover on Nissan Almera with engine MR18DE Pay attention to the fragility of the plastic ventilation pipes. They often break down in the cold, and replacing them may require removing the intake manifold.
What to do if the cover bolts are stuck?
If the bolts do not come off, do not use brute force. Use a penetrating lubricant (WD-40) and give it time to work. You can carefully heat the bolts with a hair dryer, but not with an open fire, so as not to melt the plastic of the lid.
Selection of original parts and high-quality analogues
The aftermarket offers a wide range of options, but not all of them are suitable for Nissan Almera Classic. The original part (OEM) ensures maximum durability and exact fit. However, the price of the original can be quite high, which forces many car owners to look for alternatives. High-quality analogues from well-known brands are often not inferior to the original in terms of characteristics, but are cheaper.
When choosing an analogue, pay attention to the material of manufacture and the thickness of the gasket. Some cheap Chinese copies use too thin plastic, which becomes deformed even when the engine first warms up. Also check the presence of all necessary holes for sensors and ventilation pipes. An incorrectly selected part can cause it to simply not fit into place or to dangle.
| Part type | Brand / Manufacturer | Indicative resource | Features |
|---|---|---|---|
| Original | Nissan (13270-AL00A) | 150,000+ km | Ideal geometry, high-quality plastic, durable gasket |
| Analogue Premium | Elring, Victor Reinz | 100,000 - 120,000 km | High quality gasket, often complete with sealant |
| Analogue Standard | Febi, SWAG | 80,000 - 100,000 km | Good value for money, trusted suppliers |
| Budget option | Various Chinese brands | 30,000 - 50,000 km | Risk of deformation, often require additional sealing |
It is important to note that even when purchasing a high-quality analogue, it is recommended to immediately replace the gasket if it is not included with the lid. Complete replacement guarantees no leakage for a long time. Skimping on the gasket can lead to the new cover quickly losing its seal due to the old rubber.
The original Nissan Almera Classic engine cover lasts the longest, but high-quality analogues from the Elring or Victor Reinz brands are an excellent alternative if the installation technology is followed.
Step-by-step instructions for replacement and sealing
Installing a new cover requires careful preparation and adherence to technology. After cleaning the seat on the block head, it is necessary to apply a thin layer of a special high-temperature sealant in places where the gasket may not fit tightly (usually corners and joints with the block). Do not apply too much sealant, otherwise it may get inside the engine and clog the oil passages.
Install a new gasket on the cover if it is not sealed at the factory. Make sure it sits flat and doesn't protrude over the edges. Carefully replace the cover, observing the direction of the pipes. Tighten the bolts in two stages: first by hand to align the cover, and then with a torque wrench to the tightening torque specified in the service book. Typically this value is around 8-10 Nm, but it is better to check the current data for your modification.
Момент затяжки болтов крышки: 8-10 Нм (проверьте спецификацию для вашего ДВС)After tightening all the bolts, make sure that all ventilation pipes are connected and securely secured with clamps. Connect the sensor connectors and install the decorative casing. Start the engine and let it idle for 5-10 minutes. Carefully monitor the junction of the cover and the block head for the appearance of fresh smudges. If there are no leaks, the repair can be considered successful.
Before applying sealant, wipe surfaces with a degreaser (isopropyl alcohol) to ensure maximum adhesion and prevent oil from getting into the bonding area.
Common repair mistakes and how to avoid them
One of the most common mistakes is over-tightening the bolts. The plastic cover does not have high compressive strength, and too much torque may cause it to crack or become deformed. As a result, even with a new gasket, tightness will not be achieved and the oil will begin to flow again. Always use a torque wrench and follow the manufacturer's instructions.
Another mistake is using the wrong sealant. Conventional automotive sealant may not withstand high temperatures in the exhaust manifold area and may begin to deteriorate. Use only specialized heat-resistant compounds designed for use with the engine. It is also important to prevent sealant from getting inside the engine, as this can lead to oil starvation and failure of the turbine or hydraulic lifters.
- ❌ Do not tighten the bolts “all the way” without controlling the tightening torque.
- ❌ Do not use sealant if the gasket is of high quality and fits tightly.
- ❌ Do not install the cover on a dirty or wet surface.
- ❌ Do not ignore checking the ventilation pipes before installation.
If you are not confident in your abilities or do not have the necessary tools, it is better to entrust the work to professionals. Incorrect installation can lead to serious consequences for the engine. Professional repair will save you time and money in the long run while ensuring your vehicle runs reliably.
⚠️ Attention: If after replacing the cover the engine continues to run noisily, check the condition of the hydraulic compensators. Perhaps the problem is not in the cover, but in the wear of the gas distribution mechanism, which requires more complex repairs.
FAQ: Frequently asked questions from Nissan Almera Classic owners
Why does the Nissan Almera Classic engine make noise after replacing the cover?
The noise may persist if the hydraulic lifters have been damaged or the valve clearances have already worn out. It is also possible that the new gasket is too thick or that the sealant got into the oil channels, disrupting the oil supply to the expansion joints.
Is it possible to drive with an oil leak from the valve cover?
For a short time - yes, but only to the point where the oil does not drip onto the ground. Long-term operation with a leak is dangerous: oil can get on the timing belt and cause it to break, or on a hot manifold, which will lead to a fire.
How often do you need to change the engine cover on a Nissan Almera Classic?
The cover itself lasts a very long time, often up to 200,000 km or more. However, it is recommended to change the gasket every 100,000 km or when the first signs of a leak appear. If the cover is deformed or cracked, it must be replaced immediately.
Do I need to remove the intake manifold to replace the cover?
On some engine modifications MR18DE The rear cover bolts are difficult to access and removing the intake manifold makes the process easier. However, if there are flexible pipes and sufficient space, you can do without completely dismantling the collector.
What is the best sealant to use?
It is recommended to use high temperature silicone based sealants such as Permatex Ultra Black or Loctite 5910. They are resistant to temperatures up to 300°C and oils, providing a reliable seal.