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If you own a Nissan Patrol Y61 / GU with a 3.0-liter ZD30 turbo diesel, these are invaluable tips to help you increase the life of your engine …
The ZD30 engine has suffered a bad reputation for premature failures, including melting / cracking and overshoot pistons, largely due to a few common problems. These engines are powered by an ECU controlled boost variable span turbocharger, and to meet stringent European emission standards, run an Exhaust Gas Recirculation (EGR) system. Running fairly high factory boost levels makes the ZD30 a heavy breathing engine and oil vapor is forced into the intake tract contaminating the Mass Air Flow (MAF) sensor, making its way through the intercooler and into the intake manifold. The EGR system can turn this oil vapor into a thick, tar-like consistency, blocking the intake channels, which in turn can cause some cylinders to run rich and others poor, resulting in melted pistons …
What can be done to maximize engine life?
1. Install an oil / air separator (collecting pan). This will reduce the amount of oil vapor / leak entering the air intake system.
2. Regularly clean the Mass Air Flow (MAF) sensor located on the intake tube near the air box. A contaminated MAF sensor can cause faulty signals to the ECU, resulting in excessive boost. The proper MAF cleaners are available at your local auto parts store.
3. Fit a boost gauge and an Exhaust Gas Temperature Gauge (EGT). While this won’t prevent anything, it will alert you to any warning signs.
4. Install a free flow exhaust system, this will drastically reduce EGT. We install and recommend 3 “mandrel bent exhaust systems.
5. Never put a “Chip” on without also making the exhaust system. A chip will increase the amount of fuel in the engine, increasing the temperature of the exhaust gases, which is why a free-flow exhaust system is required to reduce EGTs. We use and recommend Steinbauer and DP chips.
6. If you notice boost pressure spikes greater than 20 psi (up to 25 psi is not uncommon), install a boost limiting device, such as a dawes valve. These can be set so that the turbo cannot exceed say 18psi … This is a band-aid, not a cure, as there will be other problems causing the overboosting.
7. If your intercooler appears to be leaking oil, it may also lose boost pressure. Replacement units are available where the tanks are welded in place of the factory crimp fittings.
8. Have the inlet manifold removed and cleaned. We have seen entry corridors closer to the EGR blocked by almost 50%.
9. Although illegal, there are EGR blanking kits available.
10. ZD30s need regular oil changes, every 5000k is recommended.