D40 Navara Problems: Top 4 Common Issues & Solutions

Nissan D40 Navara problems that affect its performance and reliability. Here we discuss the top 4 issues and give you solutions on how to avoid or fix them.

Nissan D40 Navara problems and solutions

Nissan Navara D40 automatic transmission problems

The automatic transmission heat exchanger or cooler is one of the common Nissan Navara D40 problems. The cooler within the engine’s radiator may develop leaks or fail and cause coolant and transmission oil to mix.

Also, due to the internal rupture of the radiator, this allows engine coolant to enter the Megatronic, an electronic control system located inside the transmission. This problem can be a challenge when coolant and oil mix.

The solution is to bypass the existing cooler and purchase an external automatic transmission oil cooler* (eBay affiliate link). This separates the transmission cooler from the radiator and avoids the problem.

Engine Oil Cooler failure

The engine oil cooler on a Nissan Navara D40 2.5 turbo diesel is crucial for maintaining optimal oil temperature and preventing overheating. However, there have been reports of oil cooler failures in some cases.

If the oil cooler is damaged or has a leak, it can allow engine oil to mix with the coolant. This can occur if there is a rupture in the oil cooler housing or a failure in the oil cooler seals.

Other symptoms of engine oil in the coolant are:

  1. Blown Head Gasket: A blown head gasket can cause the mixing of engine oil and coolant. When the gasket fails, it allows oil and coolant passages to mix, leading to oil contamination in the coolant system.
  2. Cracked Cylinder Head or Engine Block: A crack in the cylinder head or engine block can create a pathway for oil to enter the coolant passages, resulting in oil mixing with the coolant.
  3. Internal Engine Damage: In rare cases, internal engine damage, such as a cracked piston or a damaged cylinder wall, can cause oil to enter the coolant.
Engine oil mixing with the coolant in the radiator from a faulty engine oil cooler on a Nissan Navara D40.
Nissan Navara Problems – Cracked Oil Cooler Symptoms

When you observe engine oil in the coolant, it is recommended to have the vehicle inspected by a qualified mechanic. They will be able to diagnose the specific cause of the issue and recommend the necessary repairs to resolve it. Ignoring this problem can lead to further damage to the engine if left unaddressed.

The image above comes from a mobile pre-purchase inspection by BPC Auto Inspect. It shows oil mixing with the water in the radiator resulting from a faulty engine oil cooler.

Nissan Navara common problems with clutch and solutions

Some owners of early Navara D40 models are experiencing clutch problems. This includes slipping following a burning smell, resulting in premature clutch wear.

The Nissan Navara Forum mentions the problem is due to the release bearing seizing. Thus not allowing the clutch to disengage. The clutch remains in contact with the dual mass flywheel, leading to a rapid failure.

Later models of the Nissan Navara came with an updated clutch, flywheel, and pedal box. If you own a Navara and need to replace your clutch and dual-mass flywheel, there is a less expensive option. Many owners choose to fit an aftermarket heavy-duty clutch and solid flywheel (single mass).

How to check for a slipping clutch?

A common and useful method mechanics use to check for clutch slippage and determine if the clutch is gripping the flywheel properly is the clutch stall test. Here’s how you can perform this test:

  1. Find an Open Area: Choose a safe and open area to perform this test, away from traffic and obstacles.
  2. Engage Handbrake: Ensure the handbrake is engaged securely to prevent the vehicle from moving.
  3. Put the Car in 4th Gear: Shift the transmission into 4th gear (or a higher gear if necessary).
  4. Rev the Engine: Depress the clutch pedal fully and rev the engine to a moderate level (around 2500-3000 RPM).
  5. Release the Clutch Quickly: Release the clutch pedal quickly while maintaining the engine speed. If the clutch is in good condition, the engine should stall immediately, and the car should not move.
  6. Observe the Results: If the engine continues to run, and the car doesn’t stall even after releasing the clutch, it’s a sign of clutch slippage, indicating that the clutch is not gripping properly.

Performing this test can help you detect clutch slippage issues. If the test indicates that the clutch is slipping, it’s a good idea to have it inspected and possibly replaced by a qualified mechanic, as continued clutch slippage can lead to further damage and decreased performance.

Nissan Navara D40 timing chain symptoms and fix

Unfortunately, the Nissan Navara timing chain including the Pathfinder (2.5L turbo diesel YD25 engine) wears out. This problem is common to other make and model vehicles like the Audi A4 or Mini Cooper.

If you hear any strange noises like rattling, scraping, clicking, or grinding when you start up your engine, don’t ignore them. The problem will still be there even if the noise has stopped. Be sure to get it checked out before further damage occurs.

The YD25DDT Turbo Diesel engine has a 2.5-litre turbo diesel. Using both a single-row primary timing chain (lower) and a double-row secondary timing chain (upper).

There have been a few incidents of the primary simplex timing chain (single-row) stretching. The vacuum pump sprockets, shaft and guides also show signs of wear and tear.

If the timing chain stretches, it can cause its valves and pistons to hit each other. This can lead to significant engine damage requiring an engine rebuild or replacement.

It’s advisable to change simplex timing chains and tensioners before 80,000 kilometres. Also, inspect them every 40,000 km.

The solution to prevent premature wear and failure is to fit aftermarket double-row timing chain kits available from eBay. These have become available for increased long-term reliability and usability.

Frequently Asked Questions (FAQ)

Which Navara to avoid?

Despite its reliability, the Nissan Navara has been reported to present several issues, especially regarding its YD25DDTi diesel engine models in the D22 and D40 generations.

Which Nissan Navara has engine problems?

The Nissan Navara is a well-known 4×4 with an excellent reputation for providing reliable and robust performance. It continues to be a popular choice among 4WD owners, who are generally satisfied with its dependability. But, if you currently own or are thinking of buying a used D22, D40 Navara, or Pathfinder with a 2.5-litre diesel engine, need to be aware of an issue related to premature timing chain failure in their YD25 engine. This can cause major internal engine damage if the chain breaks.

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