Gas distribution mechanism on Nissan Almera N16 with QG series engines is one of the most critical node systems that requires close attention of the owner. Incorrect installation timing marks when replacing the belt, it can lead to fatal consequences, such as bending of valves and destruction of the piston group. Many car owners are trying to save money on service, but the complexity of combining marks on this car requires high accuracy and understanding of the operating principles tension roller.
Features of the engines QG15DE and QG18DE, installed on Nissan Almera N16, is the use of a hydraulic tensioner, which often fails before the belt itself. Ignoring the condition of this unit leads to belt slipping even when the marks are set correctly. In this article we will look in detail at how to find top dead center, how to check the functionality of the tensioner and what tools are needed for high-quality repairs without errors.
Preparation of the workplace and necessary tools
Before disassembling the engine, it is necessary to ensure access to the attachments. To work with Nissan Almera N16 a lift or pit will be required, since access from below to the crankshaft pulley is extremely limited. Remove the battery and air filter to get a full view of the top of the engine.
The list of tools should be as complete as possible to avoid stopping the process halfway. You will need 10, 12, 14, 17 and 19 millimeter wrenches, as well as a specialized fixing tool camshaft gears. Don't forget about a jack and engine support to remove the right cushion.
- 🛠️ Set of socket heads with extensions and cardans
- 🔧 Special camshaft retainer (or homemade plate)
- 🔦 Powerful flashlight for illuminating hard-to-reach places under the casing
It is important to note that on some modifications Nissan Almera N16 The right engine mount is made of aluminum and can be brittle under extreme force. When unscrewing the mounting bolts, be careful not to damage the threads in the cylinder block. If you are planning a replacement pumps, then immediately prepare new sealant and antifreeze, since this unit cannot be removed without draining the coolant.
Removing attachments and protective covers
The first step is always to remove the alternator belt and any pulleys that interfere with access upper crankshaft pulley. On the QG18DE engine this includes the alternator, air conditioning compressor (if not removed with bracket) and power steering hydraulic pump.
Remove the plastic timing belt guard by unscrewing the bolts around the perimeter. Please note that the lower part of the casing is often bolted to the cylinder block via a bracket, which also needs to be removed. After this you will see the top timing belt and camshaft gears.
- 🔑 Loosen the tension on the alternator belt by unscrewing the lock nut on the bracket
- 🔩 Remove the generator so as not to damage its wiring during further manipulations
- 🔧 Remove the crankshaft pulley by fixing the flywheel through the hatch in the gearbox housing
Fixing the flywheel is a critical moment. Insert a screwdriver or a special stopper through the access window in the clutch housing to lock the crankshaft in one position. This will allow you to unscrew the central bolt of the crankshaft pulley without the risk of turning the engine. If the bolt does not budge, use a hammer or a long wrench, but be careful.
Installing the engine in the TDC position and checking the marks
The most critical stage is the alignment of the timing marks. Rotate the crankshaft clockwise until the mark on the intake camshaft gear aligns with the mark on the rear timing cover. On the engine Nissan Almera N16 this mark is a groove on the gear, which should be directed straight up.
Then check the mark on the exhaust camshaft gear. It should also match the mark on the body. It is important to ensure that both camshafts are in the correct position at the same time. If the marks do not match, it means that the belt has already jumped or the engine has not been cranked correctly.
For final fixation, use a special camshaft gear clamp. It is inserted into special grooves on the gears and must fit tightly to the cover. If the latch does not engage, it means you have not reached top dead center exactly. Do not try to force the retainer in as this may damage the gears.
- ✅ The mark on the intake gear must match the mark on the back cover
- ✅ The mark on the release gear must also match its mark
- ✅ The camshaft retainer must fit freely into the grooves without gaps
⚠️ Attention: Never crank the engine by the camshaft gear or timing belt! The crankshaft should only be rotated clockwise by the pulley bolt. Reverse rotation may disrupt valve timing.
- QG15DE
- QG18DE
- QG20DE
- Other
Replacing the tensioner and pump
Hydraulic timing belt tensioner on Nissan Almera N16 is a consumable item that must be replaced every time the belt is changed. An old tensioner may not hold pressure, which will lead to belt slipping and marks breaking during operation. Before installing a new device, you need to check its operation.
The new tensioner must be compressed and secured with a pin or wire before being installed on the engine. This is done so that it does not move forward ahead of time. After installing in place and tightening the bolts, the pin is removed and the tensioner smoothly begins to press on the roller.
The cooling system pump is driven by the same timing belt. If it starts to make noise or leak, replacement is required. When dismantling the pump, be sure to clean the surface of the cylinder block from old sealant and rust to ensure the tightness of the new assembly. Use only high quality sealant for cooling systems.
☑️ Checking the condition of the components before installing a new belt
Pay attention to the condition of the crankshaft oil seal. If there are signs of oil leakage, it needs to be replaced. Oil that gets on the timing belt will lead to rapid wear and destruction. The oil seal is replaced after removing the crankshaft pulley, which requires care so as not to damage the working edge during installation.
⚠️ Attention: When installing a new tensioner, make sure that it is not overtightened. Excessive belt tension will lead to rapid wear of the roller bearings and camshafts, and insufficient belt tension will lead to slippage.
The process of installing a new belt and final tension
Start installing the timing belt from the crankshaft gear, then pass it through the pump, tension pulley and camshaft gears. Make sure that the belt does not twist and sits tightly in the grooves of all gears. It is important to follow the tension order: first tension the branch between the crankshaft and camshafts, then adjust the tension roller.
Remove the clamp from the tensioner, allowing it to push out the pulley and tension the belt. Make sure that the marks on the camshaft and crankshaft gears remain in place. If the marks have moved when removing the tensioner clamp, the procedure must be started again. This is a common mistake that inexperienced craftsmen make.
After tensioning, you need to turn the engine two turns clockwise several times and check again that the marks match. The camshaft retainer should snap into place without effort. If it does not stand up, the belt is either too tight or too tight and will need to be readjusted.
What should I do if the labels do not match after scrolling?
If after two engine revolutions the marks do not match, then the belt was installed incorrectly. It is necessary to remove the belt, set TDC again and make sure that the camshaft lock fits tightly. Often the problem lies in worn gears or a stretched old belt that you use as a reference.
- 🔄 Rotate the engine by the crankshaft bolt two full turns
- 👀 Visually check that all marks on the gears match
- 🔍 Make sure the camshaft retainer fits into the grooves
Correct timing belt tension is a balance: the roller must be in the working position, and the camshaft lock must be in place without gaps after cranking the engine two turns.
Engine assembly and operation check
Once all the marks have matched, you can begin assembly in the reverse order. Install the crankshaft pulley, tighten the bolt to the required tightening torque. Replace the right engine mount, alternator and accessory belt. Don't forget to add antifreeze if you replaced the pump.
Before starting the engine, let it sit for a few minutes to allow the oil to circulate throughout the system. Start the engine and listen to the work. There should be no extraneous sounds from the timing belt, clicks or whistles. Check the oil and antifreeze levels, as well as the absence of leaks in the places where the seals and gaskets are installed.
For the first 500-1000 kilometers of operation after replacing the timing belt, it is recommended to monitor the belt tension and the condition of the tensioner. If noise occurs, stop immediately and check the system. Operating an engine with an incorrectly installed timing belt may lead to costly major repairs.
| element | Tightening torque (Nm) | Note |
|---|---|---|
| Crankshaft pulley bolt | 100 + additional turn | Use thread locker |
| Camshaft gear bolts | 100 | Tighten crosswise |
| Timing tensioner bolts | 25 | Metric thread |
| Alternator pulley bolts | 25 | Check the condition of the pulley |
| Pump bolts | 10 | Maintain consistency |
⚠️ Attention: The tightening torque of the crankshaft pulley bolts is critical. Insufficient tightening can lead to loosening of the bolt and destruction of the pulley, and excessive tightening can lead to stripping of the threads in the crankshaft.
Save the old marks on the timing belt (if there were any) or take a photo of the position of the marks before removing the old belt. This will help you quickly check that the new belt is installed correctly during subsequent maintenance.
FAQ: Frequently asked questions when replacing the timing belt on Almera N16
Is it possible to change only the timing belt without the tensioner?
Strongly not recommended. Hydraulic tensioner on Nissan Almera N16 has a limited resource and often fails before the belt. Installing a new belt on an old tensioner is highly likely to cause the marks to slip and break in the near future.
Do I need to change the alternator belt along with the timing belt?
Preferably. Since access to the alternator belt requires significant effort to disassemble the attachment, it is logical to replace it at the same time. This will save time and money in the future. Inspect the belt for cracks and delamination.
What happens if the labels are mixed up during installation?
If the marks are set incorrectly, the engine may not start, may operate unstably, or, worst of all, the valves will meet the pistons. On QG series engines, this is almost guaranteed to lead to bent valves and the need for a major engine overhaul.
How often do you need to change the timing belt on a Nissan Almera N16?
The manufacturer recommends changing the belt every 60,000 - 90,000 km or every 5 years, whichever comes first. However, given the age of many Nissan Almera N16, it is better to focus on the mileage of 60,000 km and the condition of the belt during inspection.
Is it possible to check the marks without removing the belt?
No, to accurately check and adjust the valve timing, you need to remove the protective covers and visually verify that the marks on the camshaft and crankshaft gears match. The use of a special camshaft clamp is mandatory for accurate diagnosis.