WHAT ARE YOUR OPTIONS?
RATHER than an EGR being the issue as so many people believe, the problem is the inlet manifold becoming clogged from a build-up of oil residue and exhaust soot. Remove either one and there’s no longer an issue. Luckily, one is a whole lot easier to do than the other. “Most people can get away with fitting a decent catch can like a Provent to remove the oil vapor,” Stephen said. “If that’s done, most of the exhaust gas soot goes straight through without sticking to the inlet manifold.”
It’s worth mentioning there are varying quality levels when it comes to catch cans, with a price spectrum that ranges from spare change to a few hundred dollars. On the budget end is your typical alloy box with an inlet and outlet. The problem is these rely on magic to remove the oil from the air, which isn’t too successful and can often have issues like reduced openings that can cause a build-up of pressure inside the engine. This can cause gaskets and seals to blow out from the inside, resulting in an engine literally pumping its oil out the dipstick tube.
Quality items will generally run a filter element, which will remove the oil from the air as it passes through and drastically cut down any oily residue in the inlet track and prevent the exhaust soot from building up. These filters are often either plumbed back into the sump, or are manually drained to remove the oil build-up. To prevent over-pressurisation if something is clogged, they’ll often have a pressure release system as well.
The other, more drastic approach is to remove the EGR system itself. With no exhaust soot going through the intake system there’s nothing to stick to the oily residue. In simple engines this can be achieved by physically installing a blockoff plate that will stop the gases flowing through the system, although most modern engines will register the block and throw a fault code, possibly causing your 4x4 to go into limp mode.
In many late-model vehicles a custom tune can instead stop the valves from ever opening, but that does come with more issues than it’s worth.