Engine MR18DE, installed on Nissan Almera Classic, is famous for its reliability, but the life of the gas distribution mechanism (GRM) often becomes a stumbling block for owners. Many people mistakenly believe that the chain on this motor is “eternal,” but service statistics indicate the opposite. Ignoring timely replacement leads to costly repairs to the cylinder head.
The process of replacing the timing chain with Nissan Almera Classic requires careful preparation and special tools. Incorrect installation of marks or the use of low-quality components can lead to collision of valves with pistons. In this article we will analyze all the nuances of diagnostics, selection of spare parts and the work itself.
Signs of timing chain wear and diagnostics
The first and most obvious signal about the need for replacement is extraneous noise from the engine. The sound resembles a metallic clanging or ringing, which increases during cold starts and may subside as the oil warms up, but later appears constantly. If you hear this sound, stop using the vehicle immediately.
In addition to noise, problems with the timing belt may be indicated by errors in phase sensors. The engine ECU detects a desynchronization between the crankshaft and camshaft, which causes the Check Engine Light to come on. The error often has a code P0011 or P0340, indicating a shift in valve timing. In some cases, the car may stall at idle or lose power when accelerating.
Visual diagnosis is only possible with partial disassembly. If you remove the timing cover, pay attention to the condition of the tensioner and dampers. A worn chain often has an increased link pitch, which is visible to the naked eye when compared with a new one. It is also critical to inspect the sprockets for wear.
- 🔊 Constant metallic ringing from under the timing cover at idle speed
- ⚠️ The Check Engine indicator lights up with errors in valve timing
- 📉 Loss of dynamics and unstable engine operation at idle
Selection of spare parts and necessary tools
The quality of the repair directly depends on what parts you choose. Original chain Nissan has a high resource, but its cost may be unreasonably high for a budget car. There are many high-quality analogues, such as Dayco, INA or Gates, which have proven themselves to be the best. It is important not to skimp on the hydraulic tensioner and dampers, since the old chain will quickly stretch the new one if the tensioner does not work correctly.
To carry out the work you will need a specialized tool. Without a camshaft clamp and a crankshaft clamp, it is almost impossible to set marks accurate to a degree. You also cannot do without a wrench to unscrew the crankshaft pulley, since the tightening torque there is very high. A regular wrench may not do the job, so it is better to use a pneumatic tool or a long lever.
Be sure to purchase sealant and new gaskets for the timing cover and pan. Reusing old gaskets will cause oil leakage, which will create further problems in the future. Also prepare a container to drain the coolant, since when removing the pump, some of the antifreeze will inevitably leak out.
- 🛠️ Camshaft lock (special key for Nissan)
- 🔧 Torque wrench with a range from 20 to 100 Nm
- 💧 Container for draining coolant and a set of heads for 10, 12, 14, 17, 19, 22
- Up to 100,000 km
- 100-150,000 km
- More than 150,000 km
- Haven't changed it yet
Step-by-step replacement instructions
Before starting work, it is necessary to remove the front wheel and engine mudguard to gain access to the lower part of the timing belt. Remove the alternator belt and crankshaft pulley. To do this, lock the crankshaft through the hole in the clutch housing or use a special clamp. Unscrew the pulley bolt and remove it to gain access to the upper timing cover.
Next, remove the top cover and set the engine to the TDC (top dead center) position of the first cylinder. Align the mark on the camshaft sprocket with the mark on the engine housing. Insert the camshaft clamp into the special holes in the cylinder head. Only then can the chain tensioner be loosened. Be prepared for the chain to sag, so hold it with your hand.
Remove the old chain and sprockets. Install the new chain in order: first on the crankshaft, then on the camshaft. Make sure the colored chain links match the markings on the sprockets. Insert the new hydraulic tensioner and press it all the way, then release the stopper. Start the engine and check for any abnormal noise.
☑️ Preparing to replace the chain
⚠️ Attention: Do not try to turn the crankshaft counterclockwise with the chain removed or with the tensioner disconnected - this may cause the chain to jump and damage the valves.
Features of working with a tensioner
The hydraulic tensioner on the MR18DE motor has an internal locking mechanism. Before installation, it must be completely recessed and secured with a plastic pin or thin wire, otherwise it will not work after starting the engine and the chain will dangle.
Difficulties and pitfalls
One of the main difficulties when replacing a chain with Nissan Almera Classic is access to the lower bolts securing the timing cover. They are often located in hard-to-reach places where suspension and body elements interfere. In some cases, it is necessary to remove the engine mounts or subframe, which significantly increases the work time. If you're doing this yourself, stock up on extensions and universal joints.
Another problem is the condition of the crankshaft oil seal. If it begins to leak, it must be replaced. Removing an old oil seal often leads to damage to the seat if not done carefully. Use a special puller or carefully pry it off with a screwdriver without scratching the metal.
It is also worth paying attention to the condition of the sedatives. On older engines they often crumble due to time and temperature. Plastic fragments can get into the oil system and clog the oil receiver screen, which will lead to oil starvation and engine seizure. Inspect all oil system passages before reassembly.
- 🚫 Difficult access to the lower bolts of the timing cover without removing the supports
- 💥 Risk of damage to the oil seal seat during dismantling
- 🛢️ The need to clean the oil system from fragments of dampers
Before starting work, be sure to mark the position of the crankshaft pulley relative to the body so as not to make a mistake when setting TDC if the marks are erased.
Cost of work and terms
The average cost of replacing a timing chain at a service center varies depending on the region and the qualifications of the technicians. The work takes from 4 to 8 hours, which is reflected in the price. If you decide to do everything yourself, you will save on labor costs, but will spend time finding a tool and learning the technology.
The table below shows the approximate cost of spare parts and labor at the moment. Prices may vary depending on exchange rates and suppliers.
| Name | Original | Analogue |
|---|---|---|
| Timing chain | 12 000 - 15 000 ₽ | 5 000 - 7 000 ₽ |
| Set of tensioners and dampers | 8 000 - 10 000 ₽ | 3 500 - 5 000 ₽ |
| Crankshaft oil seal | 1 500 ₽ | 600 ₽ |
| Service operation | 15 000 - 20 000 ₽ | |
⚠️ Attention: Do not delay replacement if you notice noise. A stretched chain can jump 2-3 teeth even during sharp acceleration, which will lead to the valves meeting the pistons and a major engine overhaul costing from 50,000 rubles.
Regularly checking the chain tension and condition of the stabilizers at a mileage of 100,000 km will help avoid sudden breakage and costly repairs.
Common mistakes when replacing
The most common mistake is incorrectly setting labels. Even a slight deviation of 1-2 teeth will lead to a violation of the valve timing. The engine will run unstably, fuel consumption will increase and power will decrease. In the worst case, this will lead to burnt valves due to incorrect ignition timing.
Ignoring an oil change after repair is also a serious mistake. During operation, wear products from the old chain and metal particles accumulate in the engine. If the oil and filter are not replaced, the new chain will quickly lose its properties due to contaminated lubricant. Immediately after replacing the chain, refill with fresh, high quality oil.
Another mistake is trying to save money on a hydraulic tensioner. An old tensioner may not hold oil pressure, causing the chain to sag and hit the body. This will cause noise and accelerate wear. Always install a new tensioner with the chain; it's inexpensive but critical to reliability.
FAQ: Answers to popular questions
What is the mileage of the timing chain on a Nissan Almera Classic?
Officially, the manufacturer does not indicate the exact resource, but in practice the chain lasts from 150,000 to 200,000 km. However, if you drive aggressively or use low-quality oil, this period can be reduced to 100,000 km.
Is it possible to replace the chain without removing the engine?
Yes, the chain on the MR18DE motor can be replaced without removing the engine. However, for ease of access to some bolts, it is sometimes necessary to remove the subframe or engine mount, but this does not require complete dismantling of the power unit.
What happens if the labels are mixed up during installation?
If the marks are set incorrectly, the engine may not start, run rough or stall. In severe cases, during startup, valves may collide with the pistons, which will lead to their bending and the need for major repairs.
Do I need to change the pump when replacing the chain?
It is recommended to change the pump at the same time as the chain, since it is driven by the same timing belt (in some modifications) or is located in the access zone. If the pump leaks later, you will have to disassemble half of the engine again. This is a reasonable saving of time and effort.
How often should chain tension be checked?
It is recommended to check the condition of the chain at every maintenance, especially after 100,000 km. Pay attention to noise during cold starts and errors on the instrument panel.