If you own a Nissan Patrol Y61/GU with a 3.0 liter ZD30 turbo diesel engine, here are invaluable tips to help you increase the life expectancy of your engine…
The ZD30 engine has gotten a bad reputation for premature failure including melting/cracking pistons and overcharging, largely due to a few common issues. These engines are powered by an ECU-controlled variable-vane turbocharger with boost and, to meet stringent European emissions standards, are powered by an exhaust gas recirculation (EGR) system. Running fairly high boost levels from the factory 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 to the inlet manifold. The EGR system can convert this oil vapor into a thick tar-like consistency, blocking the intake runners, which in turn can cause some cylinders to run rich and some lean, resulting in melted pistons…
What can be done to maximize engine life?
1. Install an air/oil separator (catch pot). This will reduce the amount of blown/oil mist entering the air intake system.
2. Periodically 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 overshoot. Suitable MAF cleaners are available at your local auto parts store.
3. Install a boost gauge and an exhaust gas temperature (EGT) gauge. While this won’t prevent anything, it will give you notice of any warning signs.
4. Install a free flowing exhaust system, this will drastically reduce EGTs. We install and recommend 3″ mandrel bent exhaust systems.
5. Never fit a “Chip” without also doing 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-flowing exhaust system is required to reduce EGTs. We use and recommend Steinbauer and DP chips.
6. If you notice boost pressure spikes of more 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 be boosted above, say, 18 psi… This is a Band-Aid, not a cure, as there will be other issues causing the overboost.
7. If your intercooler appears to be leaking oil, it may also have a boost pressure leak. Replacement units are available where the tanks are welded on instead of the factory crimp fittings.
8. Have intake manifold removed and cleaned. We have seen intake ducts closest to the EGR blocked by almost 50%.
9. Although illegal, their EGR blanking kits are available.
10. ZD30’s need regular oil changes, every 5000k is recommended.
