Fit an extra oil separator to filter breather fumes:

The problem:

The breather hose on the tappet cover of the Terrano runs through an oil separator and then back into the air intake hose just before the turbo. For some reason the oil separator do filter the oil from the air. The oil are then sucked through the turbo and blown into the inter cooler. The problem is that oil is not such a good conductor of heat as aluminum. Thus the oil stays hot much longer than aluminum and the air traveling through the inter cooler. is heated instead of cooled. Hot air enters the engine which decrease the efficiency of the engine.

Have a look on the intake manifold of the engine. If there is oil on the inlet manifold chances are good that your car has this problem.

I bought a normal water trap from Gemini Air in Pretoria West. Myself and the guy there had a long discussion about the problem. He recons that if I use a oil filter which they use on compressors it might cause damage since the filter can easily get blocked. It is designed to filter air under high pressure but the air running through the breather hose is close to atmospheric pressure. So he suggested that a normal water trap, normally used on compressors, will work since the only thing you really need is the cyclonic action. (so ask for a water trap with 3/4" ports, cost about R280.00) . The air and oil moves into the trapped and are spinned around the side. Because it has different densities the oil will move downwards and the air will escape on the other side. I bought the big water trap with 3/4" in/out ports. The breather hose on the engine is also 3/4" (19mm). Also note that I used normal plastic fittings which I bought at The Irrigation shop in SIlverton. It is an elbow with a 19mm metric thread on the one end and on the other end it has the grooves for the pipe to push over. I used a 19mm rubber hose which I bought from Midas.

The water trap also has a little filter inside. If this filter gets blocked gases and pressure and build up in the engine's crank case which can force oil out at the seals. So I drilled a couple of 4mm holes in the filter to prevent it. Remember that it was designed to filter water at high pressure from the air so the big holes will not do any harm. I actually think it will work just as good if you remove the filter completely.

I decided to keep the original oil separator So the breather hose from the tapped cover still goes into the oil separator I removed the elbow shaped hose which runs from the separator to the air intake. I connected one hose on the separator side and the other one on the air intake side. The other ends were obviously connected to the water trap. The water trap works one way only so make sure you connect it correctly, there are arrows on the top of the casing indicating the direction of air flow.

The water trap fitted nicely between the diesel filter and the air filter. The only permanent alteration I made was the small 6 mm hole I drilled into the diesel filter bracket in order to fix the water trap with a cable tie.

The trap fits nicely and almost looks like a factory fitted feature.

VERY IMPORTAND:

Remember that the original problem was the oil in the inter cooler. The mod we just did will prevent further oil entering the inter cooler. You MUST now remove the oil that is already in the inter cooler. If you do not have the time or the guts to do the above mentioned modification, at least clean your inter cooler. This makes a HUGE difference in you low end performance. It is very easy to do. Just undo the two nuts and two bolts that attach the inter cooler. On the one side is a little bracket for the wiring, loosen that as well. The loosen the pipes on both ends and merely lift the inter cooler from its position.

Put the inter cooler. on the ground upside down. Now pour two cups of Lacquer thinners into the air intake ports. Block the ports off with anything like rags. Pick it up, shake it. Move it in all directions to make sure the thinners runs through the core. Take the plugs out and rinse it. Repeat the exercise. Now, VERY IMPORTAND, put the inter cooler in the sun with the one port at the top and other one at the bottom so that the thinners can drain at the bottom or evaporate at the top. After two hours put it back. When you start the engine for the first time, let it just idle for at least a minute, DO NOT rev it. Just in case there might be more thinners in the inter cooler.