Valve cover on Nissan Navara (especially models D40 And D23 with diesel engines YD25DDTi And M9T) is a small but critical detail. Its main task is to seal the top of the cylinder head, preventing oil leakage and dirt from getting inside the engine. However, over time, the rubber seal (gasket) wears out, the cover is deformed due to temperature changes, and plastic models crack - and now oil smudges appear under the hood, and the smell of burnt oil lingers in the cabin.
Owners Navara They often encounter this problem after 100–150 thousand kilometers, but in the Russian climate and low-quality fuel, the service life of the part can be halved. In this article we will look at How to diagnose a valve cover failure, which original and non-original spare parts to choose, and we will also give step-by-step instructions for replacement, taking into account the nuances for different generations of the pickup truck. We will pay special attention to typical mistakes that lead to repeated leaks a month after repair.
Symptoms of a valve cover failure Nissan Navara
The first symptoms of a problem often go unnoticed until the leak becomes massive. Here's what you should pay attention to:
- 🔍 Oil stains under the car - especially in the cylinder head area (front or side). On Navara D40 with motor YD25 Leaks often appear near glow plugs.
- 💨 Burnt oil smell in the cabin or under the hood - a sign that oil is getting onto the exhaust manifold or other hot parts.
- 🛢️ Constantly decreasing oil level for no apparent reason (if there are no leaks from under the crankcase or seals).
- 🔧 Oiling glow plugs - on diesel Navara this may cause startup problems.
- 🚨 Oil pressure sensor errors (For example,
P0524) - rare, but occurs with severe leakage.
On Navara D23 with motor M9T (2.3 dCi) the leak is often disguised as a leak from under the turbine, so it is important to carry out diagnostics. The simplest way to check is visual inspection: open the hood, start the engine and look at the junction of the cover with the cylinder head. If there are even small drops of oil, it’s time to change the gasket or the cover itself.
⚠️ Attention! On Nissan Navara with the system EGR An oil leak from under the valve cover can lead to clogging of the recirculation valve and increased fuel consumption. If you ignore the problem for longer than 3–6 months, repairs will cost 2–3 times more.
- YD25DDTi (2.5 dCi)
- M9T (2.3 dCi)
- QR25DE (2.5 petrol)
- Other
Original and non-original valve covers: what to choose?
When replacing the valve cover with Navara owners have three options: the original, high-quality analogues and budget substitutes. Let's look at the pros and cons of each.
| Part type | Article | Price (RUB) | Pros | Cons |
|---|---|---|---|---|
| Original (Nissan) | 11010-ED00A (D40, YD25)11010-4M00A (D23, M9T) |
8 000–12 000 | Perfect fit, long service life (150+ thousand km), no sealing problems | High price, fakes on the market |
| Analogue (Febi, Reinz) | 28516 (Febi)11-54033-01 (Reinz) |
3 500–6 000 | Good quality rubber, often better than the original for the price | May require adjustment, not always complete set (no bolts) |
| Budget analogue (Patron, Trialli) | PK-NIS016 (Patron) |
1 500–2 500 | Low price, quick solution to the problem | Service life 30–50 thousand km, often leaks in corners |
| Gasket separately | 11018-ED000 (original)71-35428-10 (Elring) |
800–2 500 | Only the seal can be replaced if the cover is intact | Requires careful installation, risk of repeated leakage |
For Nissan Navara D40 with motor YD25DDTi original cover (11010-ED00A) is made of aluminum, which increases its reliability. On D23 with M9T plastic covers are often installed (11010-4M00A), which become deformed over time. If your budget is limited, the best choice is kit from Febi or Reinz with new gasket and bolts.
Important: On Navara with the system Start/Stop (available on some versions D23) the use of non-original covers may lead to system malfunctions due to leaks.
Step-by-step instructions for replacing the valve cover
Replacing the valve cover with Nissan Navara - a task of medium complexity that can be completed independently if you have the tools. The service charges from 3,000 to 6,000 rubles for this work, so you can save significantly. Below are instructions for motors YD25DDTi And M9T.
10mm and 12mm socket wrenches|Flat head screwdriver|Sealant (Loctite 574 or equivalent)|New gasket and bolts (if included)|Carburetor cleaner or gasoline to degrease|Torque wrench (optional but recommended)
-->
Step 1. Preparation
Disconnect the battery (remove the negative terminal). On Navara D40 For convenience, you can remove the air duct and air filter housing. On D23 Additionally, you will have to disconnect the crankcase ventilation system pipe (PCV).
Step 2. Removing the old cover
Unscrew the cover bolts (usually 10–12 pieces) in the reverse order of tightening (from the edges to the center). On YD25 bolts often stick - do not use excessive force to avoid stripping the threads. After removing the bolts, pry the cover with a screwdriver (carefully so as not to damage the surface of the block head).
Step 3: Clean and install a new gasket
Thoroughly clean the surface of the cylinder head and cover from old sealant and oil. Use degreaser (For example, WD-40 Specialist). Apply a thin layer of sealant to the gasket (if it is not self-adhesive) and install it on the lid. On M9T It is important to align the bolt holes and ventilation channels.
Step 4. Installation and tightening
Replace the cover and tighten the bolts to in a certain order (usually in a criss-cross pattern) with force 8–10 Nm. Over-tightening will lead to deformation of the lid, and loose tightening will lead to leakage. On Navara D23 After installation, check the operation of the crankcase ventilation system (PCV), since its clogging is a common cause of repeated leaks.
⚠️ Attention! On motors YD25DDTi After replacing the cover, an error may appearP0401(insufficient flow EGR). This is due to oil getting into the ventilation system. To avoid this problem, blow out the hoses before installing the cover.PCVcompressed air.
1) The bolts are tightened correctly (use a torque wrench).
2) The state of the breather is on Navara it often becomes clogged, increasing crankcase pressure.
3) Quality of the gasket - budget analogues can harden in the cold.-->
Typical replacement mistakes and how to avoid them
Even experienced technicians sometimes make mistakes that lead to repeated leaks or engine damage. Here are the most common of them:
- 🔧 Using old sealant — the remains of the old sealant on the surface of the cylinder head can disrupt the tightness of the new gasket. Always clean the surface down to bare metal.
- 🔩 Uneven bolt tightening — if you tighten the bolts in a circle rather than crosswise, the cover will become deformed. On Navara D40 this often leads to leaks in the corners.
- 🛢️ Saving on gasket — installing an old gasket “just in case” or using cheap analogues without reinforcement leads to rapid wear.
- 🚫 Ignoring the ventilation system - clogged valve
PCVor the hoses create excess pressure in the crankcase, which squeezes out oil even through a new gasket. - 🔥 Starting the engine immediately after replacement — the sealant needs 1–2 hours to polymerize. On Navara with a turbine it is better to wait 3-4 hours.
Another common problem is retightening of bolts. On aluminum covers (D40) this leads to cracks, and on plastic ones (D23) - to deformation. The optimum torque for valve cover bolts is Nissan Navara — 8–10 Nm. If you don't have a torque wrench, hand-tighten the bolts until they are snug, then back 1/4 turn.
What should I do if after replacing the cap still leaks?
1. Check the pressure in the crankcase - if it is high (due to clogged ventilation or worn rings), oil will be squeezed out even through a new gasket.
2. Inspect the lid itself for cracks (especially important for plastic lids D23).
3. Make sure that the gasket does not “sink” into the groove - this happens if the sealant is applied in too thick a layer.
4. On motors YD25 check the condition of the oil seals (valve seals) - their wear also gives similar symptoms.
Comparison of valve covers for different generations Nissan Navara
Nissan Navara was produced in several generations, and the valve cover design differs depending on the engine model. Below are the key differences:
| Generation | Engine | Cover material | Original article number | Features |
|---|---|---|---|---|
| D22 (1997–2004) | TD27Ti, ZD30DDTi | Aluminum | 11010-3W000 |
Simple design, rarely leaks. The gasket is rubber, without metal reinforcement. |
| D40 (2004–2014) | YD25DDTi, VQ40DE | Aluminum (diesel), plastic (gasoline) | 11010-ED00A (diesel) |
On diesel engines it often leaks due to wear on the gasket. Gasoline caps (VQ40) are more reliable. |
| D23 (2014–present) | M9T (2.3 dCi), YD25 (in some markets) | Plastic (with metal reinforcement) | 11010-4M00A |
Plastic is prone to deformation. New bolts with torque limiters are included. |
| NP300 (2015–present) | YD25DDTi (updated) | Aluminum | 11010-4M01A |
Improved gasket with metal frame. Requires replacement less often. |
On Navara D40 with motor YD25DDTi The original aluminum lid lasts longer than its plastic counterparts, but is more expensive. For D23 with M9T it is better to choose covers with metal reinforcement (for example, from Febi), since standard plastic may not withstand temperature changes in the Russian climate.
How to extend valve cover life?
Even the best quality valve cover will not last long if you do not monitor the condition of the engine. Here are some tips to help avoid premature replacement:
- 🔄 Change your oil regularly - on Navara with diesel engines, the interval should not exceed 10,000 km (even if the manufacturer indicates 15,000). Old oil corrodes the rubber of the gasket.
- 🌡️ Monitor engine temperature - overheating deforms the lid. On YD25 And M9T The optimal operating temperature is 85–95°C.
- 🔧 Clean the crankcase ventilation system - clogged
PCV- the valve increases pressure in the crankcase, which forces oil through the gasket. On Navara D23 Cleaning is recommended every 30,000 km. - 🛢️ Use quality oil - for M9T fits
5W-30or5W-40with permission Renault RN0720. Cheap oils destroy seals. - 🚗 Avoid sudden temperature changes - if you start the engine in the cold in winter, let it warm up for 2-3 minutes before driving.
On Nissan Navara with the system Start/Stop (installed on some D23) Frequent engine starts increase the load on the cover gasket. In this case, it is recommended to check its condition every 20,000 km.
The main reason for valve cover leaks is Navara - not the gasket itself, but increased pressure in the crankcase due to a clogged ventilation system. Regular cleaning PCV-valve prolongs the life of seals by 2–3 times.
FAQ: Frequently asked questions about valve cover Nissan Navara
Is it possible to drive with a leaking valve cover?
Short-term - yes, but no more than 1-2 weeks. Driving for a long time with a leak leads to:
- Oil getting on the timing belt (risk of breakage).
- System clogging EGR and catalyst (on diesel engines).
- Fire Hazard - Oil may ignite from the exhaust manifold.
On Navara D40 with motor YD25 leakage is often accompanied by an error P0401 (malfunction EGR), which worsens dynamics and increases fuel consumption.
What sealant should I use when replacing?
For Nissan Navara fit:
- Loctite 574 — optimal for aluminum lids (D40).
- Permatex Ultra Black - universal, withstands high temperatures.
- Victor Reinz Reinzosil - recommended for plastic lids (D23).
❌ Do not use silicone sealants (for example, ABRO) - they cannot withstand the vibrations and temperatures of a diesel engine.
How much does it cost to replace a valve cover at a service center?
The cost of work depends on the region and complexity:
- Moscow/St. Petersburg: 4,000–7,000 rub. (with diagnostics of the ventilation system).
- Regions: 2,500–4,500 rub.
- Additionally: cleaning
PCV- valve - 1,000–1,500 rubles.
If you change only the gasket (without the cover), the price is reduced by 30–40%. On Navara D23 with M9T Bolts often need to be replaced (they come with the original cover).
Is it possible to install a cover from another engine?
Theoretically, yes, but with reservations:
- Cover from Renault Master (motor M9T) suitable for Navara D23, but may differ in the location of the bolt holes.
- Cover from Nissan Pathfinder (with YD25) compatible with Navara D40, but requires modification of the gasket.
⚠️ Risk: a mismatch in the breather or ventilation system can lead to leaks or increased oil consumption.
What to do if after replacement there is a knocking noise under the cover?
A knocking or clattering noise after replacing a cover is usually associated with:
- Ingress of foreign objects (for example, fragments of an old gasket) into the timing mechanism.
- Incorrect tightening of bolts - if the cover is deformed, it may touch the valves.
- Wear of hydraulic compensators (on VQ40DE) - the sound was masked by the leak, and after repair it became audible.
🔧 Solution: Remove the cover and check the integrity of the gasket and the cleanliness of the inner surface. If the knock remains, a timing belt diagnosis is required.