TRAPPING SATAN'S VEGEMITE

EMISSIONS EQUIPMENT CAN CAUSE MODERN TURBO-DIESEL ENGINES TO CHOKE ON THEIR OWN EXHAUST FUMES, UNLESS YOU FIT A QUALITY CATCH-CAN.

- DAVE MORLEY

CATCH-CANS: Can of worms, more like it. Car-makers don’t like them, some mechanics don’t understand them and four-wheel-drive owners who have them fitted tend to love them. So what’s the reality? Do you need one? Will it wreck your engine? Will it void your warranty? Will it save the day, or even the planet? Let’s break it down.

HOW DID THE CATCH-CAN COME ABOUT?

THE catch-can was initially developed for stationary diesels and the trucking industry. As recreational four-wheel-drives have become more reliant on common-rail diesel technology, so has the catch-can debate become a hot-button topic.

TWO PARTS

A good quality catch-can will feature a separate filter kit and a built-in pressure-relief kit.

DON'T CHEAP OUT

Opting for premium units like this FlashLube catchcan will save you plenty of headaches in the long run.

WHAT’S THE PROBLEM, ANYWAY?

TO ANSWER that, you need to understand what’s happening inside the modern-diesel engine. Essentially, pollution laws around the world (including here) have meant a certain percentage of the engine’s exhaust has to be directed back into the combustion chambers so the engine can have a second crack at burning it and reducing tailpipe nasties. Since the engine is now eating its own exhaust fumes, there’s a percentage of diesel soot that also gets ingested as part of that process.