Leaking engine oil from under the pulley cover or from under the gearbox is one of the most common engine problems. Nissan Almera N16equipped with QG or GA series motors. When you notice oil leaks on the bottom of the engine or on the clutch housing, the first thing that comes to mind is replacing the crankshaft oil seal. This procedure requires care, since incorrect actions can lead to misalignment of the seal and repeated leakage after just a couple of thousand kilometers.
Many owners Nissan Almera They put off a visit to the service station, believing that the oil is simply leaking out due to a clogged breather. However, if the oil level drops faster than normal and characteristic puddles form under the car, diagnostics should be carried out immediately. Front oil seal is responsible for the tightness of the attachment drive area, while rear oil seal protects the connection area with the gearbox.
Do-it-yourself replacement of the crankshaft oil seal with Nissan Almera N16 It’s entirely within the capabilities of a motorist with a basic set of tools and a little experience working under the hood. The main thing is not to rush, choose the right specialized tools for removing the pulley and use high-quality consumables, since budget analogues often cannot withstand the temperature conditions of a Japanese engine.
Diagnostics and selection of spare parts
Before starting to disassemble the engine, it is necessary to determine exactly which oil seal requires replacement. Symptoms of a problem front oil seal usually appears as oil on the inside of the front wheel, on the alternator belts and on the crankshaft pulley. If oil leaks from under the clutch housing or is seen getting onto the clutch basket, the problem lies in the rear seal.
When choosing a new spare part, it is critical to pay attention to the manufacturer. Original parts Nissan are expensive, but provide maximum durability. An alternative can be proven brands such as Corteco or Victor Reinz, which often supply compactors to the conveyor. Avoid the cheapest analogues, as their rubber quickly hardens and loses elasticity.
It is also important to check the condition of the crankshaft surface on which the seal lip slides. If there are deep grooves or corrosion on the shaft, even the best quality new oil seal will not provide a tight seal. In such cases, it will be necessary to grind the shaft or install a repair oil seal with an increased diameter.
To select the correct part number, use the VIN code of your car, since oil seals for 1.5 l (QG15DE) and 1.8 l (QG18DE) engines may have differences in design and size. An error in choosing the size will lead to the fact that the part simply will not fit into place or will sit too loosely in the seat.
Tools and workplace preparation
The success of the operation depends half on having the right tools. To remove the crankshaft pulley Nissan Almera N16 A standard set of wrenches is not enough. You will need a special puller that will allow you to unscrew the pulley bolt without the risk of damaging the threads or the shaft itself. You will also need a jack and stands to securely support the car.
It is better to carry out work on an inspection pit or a lift to provide free access to the lower part of the engine. If this is not possible, you will have to use reliable stands under the body, since working while lying on the ground with heavy parts is extremely inconvenient and unsafe. Don't forget about personal protective equipment: gloves and goggles are required.
You will also need silicone-based sealant for the lid gasket, a rag, degreaser, and a container to drain the oil (if you plan to change the oil or it will leak during dismantling). Be sure to prepare a new pulley bolt, as old bolts are often subject to deformation and are not recommended to be reused.
If you plan to replace the rear seal, make sure you have a tool to remove the flywheel or clutch basket if access to the seal is blocked by these components. In some cases, you have to remove the entire transmission, which makes the task much more difficult and time consuming.
- QG15DE (1.5 l)
- QG18DE (1.8 l)
- GA16DE (1.6 l)
- Other
Replacing the front crankshaft oil seal
We begin the process by removing the engine protection and draining the coolant, if necessary to access the belts. Disconnect the negative terminal of the battery to avoid short circuits when working on electrical equipment. Next, you need to remove the alternator belt and, if necessary, the pump pulley to gain access to the crankshaft pulley.
The key step is to unscrew the central pulley bolt. To do this, you can fix the crankshaft in two ways: either by inserting a screwdriver between the teeth of the flywheel through the hatch (if there is one), or using a special pulley lock. If you use a jack to hold the pulley from turning, do so very carefully to avoid damaging the teeth.
After removing the bolt, remove the pulley. If it is tight, use a puller. Do not try to knock down the pulley with a hammer, as this may damage the bearing or the shaft itself. Make sure the pulley is removed straight and without distortion.
Now you can remove the oil seal cover. It is secured with several bolts. Carefully pry off the cover with a screwdriver, being careful not to damage the sealing surface. Remove the old oil seal. If it is seated deep, use a drift or suitable tool to force it out of its seat, but do not damage the cover body itself.
Thoroughly clean the cover seat and crankshaft surface from any remaining oil and dirt. Degrease the surface. Be sure to lubricate the new oil seal with clean engine oil before installation. This is critical to preventing the compaction from dry starting.
Install a new oil seal into the cover. Use a mandrel of a suitable diameter or an old oil seal to press the new one evenly and without distortion. The blows must be uniform around the entire circumference. If the oil seal is skewed, it will begin to leak immediately after starting the engine.
Replace the cover by applying a thin layer of sealant to the joints. Tighten the cover mounting bolts to the recommended torque. Install the pulley, tighten the new mounting bolt and secure the shaft for final tightening.
☑️ Preparing to replace the front oil seal
⚠️ Caution: Never use a hammer to drive the seal directly through a metal object, as this may deform the sealing lip. Use a wooden spacer or a special mandrel.
Features of replacing the rear oil seal
Replacing the rear crankshaft oil seal with Nissan Almera N16 - a more labor-intensive procedure than replacing the front one. Often, accessing it requires removing the gearbox, since the oil seal is located in the clutch housing. This means that you will have to remove the gear shift lever, clutch and flywheel.
Before starting work, be sure to remove the battery and disconnect all wires and cables that interfere with dismantling the gearbox. Support the engine with a jack and a wooden spacer to take the load off the engine mounts. Unscrew the bolts securing the box to the engine and carefully move it back without damaging the input shaft.
After removing the gearbox and clutch basket, you will see the flywheel. It must be removed by unscrewing the mounting bolts. Be careful: the flywheel is heavy and must be removed carefully to avoid dropping it. After removing the flywheel, access to the rear oil seal, which is pressed into the cylinder block, opens.
Press out the old oil seal and clean the seat. Install a new oil seal, lubricating it with oil. Press it in carefully, making sure it is perpendicular. Assembly is carried out in reverse order. It is important to check the condition of the clutch basket and disc, as oil from the rear oil seal often contaminates them.
When assembling the gearbox, make sure that the input shaft fits exactly into the splines of the clutch disc. Do not use excessive force when tightening the transmission mounting bolts to avoid damaging the housing. After assembly, check the clutch operation and absence of leaks.
What to do if the oil seal leaks after replacement?
If the leak persists after replacing the oil seal, check the following points: 1) Correct installation (is there any misalignment); 2) Condition of the crankshaft surface (are there any marks); 3) Pressure in the crankcase ventilation system (a clogged breather creates excess pressure); 4) Quality of the sealant (excess sealant could get inside and block the oil drain).
Checking the crankcase ventilation system
A common cause of repeated oil seal leakage is increased pressure in the engine crankcase. If the ventilation system (breather) is clogged, the air pressure inside the block will begin to force oil through any weak spots, including new seals. Therefore, before installing new seals, be sure to check the condition of the crankcase ventilation valve.
On engines Nissan Almera N16 The vent valve is often integrated into the valve cover. Remove the cover and check the condition of the oil separator. If it is clogged with dirt or oil, it needs to be washed or replaced. Ignoring this point will negate all efforts to replace the seals.
Also check the pipes leading from the valve cover to the intake manifold. They can be clogged with oil deposits, which prevents the free escape of gases. Rinse the pipes with solvent and make sure they are clear. Only with a proper ventilation system will the new oil seal last a long time.
Before installing a new oil seal, drop a little oil onto its sealing lip. This will provide lubrication in the first seconds of engine startup before the pump begins pumping oil into the seal lubrication system.
Bolt tightening procedure and sealing
Proper tightening of the oil seal cover and pulley bolts is critical. Use a torque wrench to avoid over-tightening, which can cause the cap to warp and crack, or under-tightening, which will cause vibration and leakage. The tightening torques are indicated in the service book, but usually for the oil seal cover it is about 10-12 Nm, and for the pulley bolt it is much more (about 100 Nm plus the rotation angle).
When applying sealant, use a quality silicone RTV sealant that is resistant to oil and high temperatures. Apply a thin continuous line around the perimeter of the cover, avoiding getting inside the engine. Excess sealant that gets inside can come off and clog the oil pump or filter.
Allow the sealant to cure for the time specified by the manufacturer (usually 30-60 minutes) before adding oil and starting the engine. This will ensure reliable adhesion of the cover to the cylinder block.
| Parameter | Front oil seal | Rear oil seal |
|---|---|---|
| Location | Front of engine (belt side) | Rear engine (gearbox side) |
| Difficulty of replacement | Medium (pulley removed) | High (requires removal of gearbox) |
| Probability of leakage | High (due to pulley vibration) | Medium (usually due to crankcase pressure) |
| Required Tools | Pulley puller, keys | Transmission removal kit, flywheel retainer |
| Opening hours | 1.5 - 2 hours | 4 - 6 hours |
Correct diagnosis of the cause of the leak (pressure in the crankcase or shaft wear) is more important than replacing the oil seal itself, since without eliminating the root cause, the new part will quickly fail.
Checking results and final tests
After completing all the work, do not rush to hit the road right away. First, start the engine and let it idle for 10-15 minutes. Carefully inspect the oil seal installation site for fresh leaks. Check the oil level and, if necessary, add it to normal.
Conduct a visual inspection of all removed components: belts, pulleys, bolts. Make sure nothing is left in the engine compartment. Check the operation of the generator and the belt tension if you removed it.
After the first 50-100 km, be sure to come back and check the condition of the oil seal again. Sometimes small leaks appear only after the engine has warmed up and reached operating temperatures. If there is no leak, the work can be considered successful.
Don't forget that replacing an oil seal is not only a repair, but also an opportunity to check the condition of other engine components, such as the timing belt (if you touched it) and camshaft seals. An integrated approach will allow you to avoid repeated visits to the ski lift in the near future.
Common mistakes when replacing
One of the most common mistakes is installing the oil seal without pre-lubrication. Dry starting the engine immediately after installation leads to instant wear of the working edge. Always apply oil to the edge before installation.
Another mistake is using low-quality sealant or applying it incorrectly. If sealant gets into the oil passages, it can cause serious engine damage, including seizure. Apply sealant only to the outer surface of the joint.
They also often forget to check the condition of the seat on the shaft. If there are burrs on the shaft, the new oil seal will not be able to cover them. In such cases, the shaft must be ground or a repair oil seal with an increased size must be used, which requires precise selection.
⚠️ Attention: If you are using an old pulley bolt, make sure it is not stretched. A stretched bolt may burst when tightened or become loose during operation, which will cause the pulley to fly off at high speed.
The use of a torque wrench when tightening the crankshaft pulley bolt is mandatory, since neither overtightening nor undertightening is acceptable, which can lead to destruction of the thread or unscrewing of the pulley.
How can you tell if it’s the front and not the rear oil seal that’s leaking?
If oil is leaking from the front of the engine and collecting on the pulley, belts, and inside of the front wheel, it's a front oil seal. If the oil is visible from under the clutch housing, on the clutch basket, or flows out from below in the area where the engine connects to the gearbox, this is the rear oil seal.
Is it possible to replace the rear oil seal without removing the transmission?
On the Nissan Almera N16, access to the rear oil seal is extremely limited. Theoretically, you can try to squeeze out the old one and press the new one through the hole for the speed sensor or the hatch in the crankcase, but this is extremely inconvenient and risky. It is safer and more correct to remove the gearbox for quality repairs.
What sealant is best to use for the oil seal cover?
It is recommended to use a high temperature oil resistant silicone sealant such as RTV based. Popular brands: Permatex, Loctite, Victor Reinz. Avoid using anaerobic sealants as they are designed for other types of joints.
Do I need to replace the crankshaft pulley bolt?
Preferably. The pulley bolt is often a one-time item that stretches when tightened. Reusing an old bolt may cause it to loosen or break. It is better to purchase a new original bolt.
Does a clogged breather cause oil seal leakage?
Yes, this is one of the main reasons. A clogged crankcase ventilation system creates excess pressure, which forces oil through the seals. Before replacing, be sure to clean the ventilation valve and pipes.