These days it’s quite common for people to recommend a catch can, and rightly so! Separating the oil from crank case fumes is a great idea, as it is responsible for a fair share of engine problems. But first, it’s important to understand…. why a catch can could be useful? When you should fit a catch can? What it can and can’t do to fix the issue?

During combustion, a small amount of the burnt gases get past the piston rings (blow-by), and into the engine sump. That happens even in brand new engines, and for environmental reasons, this excess sump pressure is directed into the air inlet system. Some oil vapor is also carried with it, and it’s not a problem, until blowby gets worse.

When blow by becomes excessive oil gets inside inter-coolers, intake manifolds become fouled with oil and soot. Carbon deposits form inside combustion chambers, especially around piston rings…and this increases blow by further.  Performance also deteriorates! And eventually engine life is shortened! Clearly, anything that increases blow by needs to be addressed.

Should you fit a catch can kit?

Your first line of defense before fitting a catch can is to reduce the cause of blow by, which in turn reduces oily crank case fumes. Blow by can also be caused from too much city type driving, EGR valves sticking, turbocharger coking, faulty injectors, bad fuel or malfunctions with emission control equipment, so the oily fumes that a catch can removes, are not the only factor at play.

How to reduce crank case fumes before fitting a catch can kit?

Remove existing piston ring groove deposits by using a Flushing Oil Concentrate, that is capable of dissolving and dispersing those tough-to-remove deposits.
Flushing Oil Concentrate.

Use a specific type fuel additive that actively burns off carbon and keeps the top ring area clean. It also needs to burn the fuel more cleanly to reduce exhaust soot production. There’s not too many around, but FTC Decarbonizer  is one example that actually works.

People who employ this first line of defense keep blow-by well and truly under control. They avoid inlet system fouling, while maintaining excellent reliability with low maintenance costs. There’s rarely a need for fitting a catch can, but it certainly provides added protection.

Will a catch can kit reduce crank case fumes?

An effective oil catch can (eg the Provent brand) is designed to remove oil vapors from the crankcase breather. It’s a waste of money fitting a cheap version, if it doesn’t do this. It is certainly excellent insurance against some expensive problems, and well worth fitting, especially when travelling remote. However, owners need to realize that catch cans are the second line of defense. That’s because they don’t address all the causes of blow by.  They are a band-aid fix! Catch cans certainly filter out the blow by gasses but they do not fix what is causing the fumes.

Catch cans prevent expensive repairs, but the cause of the problems remains.

If you have identified excessive engine wear as being the cause of  the blowby  you certainly need a Direction Plus catch can kit 
A catch can is recommended if you aren’t proactive in decarbonizing your engine, and maintaining clean piston rings, as it will help prevent some problems.
If you decide that a catch can is good insurance, and worth the expense, definitely buy only a quality one. Keep in mind that a catch can needs to be monitored and serviced correctly to continue functioning as intended.

If you have any questions about when to fit a catch can feel free to give the team a call on  07 33766188

Recommended products to use before fitting a catch can