Oil Catch Can

I've seen it mentioned on here a couple times. The catch cans dont seem to get a lot of love here.

I think one reason for that is because many Honda buyers just arent into modding the powertrain as much as, say, the Big3 drivers. Honda buyers tend to value the peace-of-mind of not having to mess with the powertrain. And for good reason, as Honda powertrains, over the long haul, have had a tendency to be more reliable than your average bear.

OTOH, in efforts to make more efficient powertrains, it seems Honda may be sacrificing some of their reliability. This was proven out in the previous-gen VCM.

The jury is still out on the current VCM, as well as direct injection on the Honda V6. As with the VCMuzzler, a catch can would serve as an insurance policy, of sorts. You may never need it, but if done correctly, it may prove beneficial over the long haul.

Would I get a catch can? I dunno. I believe there is merit and benefit in having a catch can, but then I also have to justify it to my wife. Then she will ask, "why are we buying a Honda if we can't trust it?". Then I will have to explain the "lesser of many evils" thing, and who knows how many other cans of worms....in that light, it is probably not worth it.

The design of the Honda engine fuel management in my opinion solves the issue pitched by those who sell catch cans. The 3.5L has a Direct Injection system that sprays fuel into the combustion chamber using injectors that have 6 ports creating a pattern that will hit the backside of the intake valves while they are still open. It then has a second injection of fuel later in the compression stroke after all valves are closed for combustion. That first injection event will clean the intake valves of any residue that may be created by PCV fumes if any.

By following several forums and advice from several manufacturers and highly skilled mechanics, I believe the best practice for an owner of Direct Injection engines is to use a Top Tier gasoline for cleaning of the combustion chambers including valves and minimization of combustion residue contributing to carbon creation. Additionally using Full Synthetic motor oil with changes at 3-5K will insure the engine is clean internally for all of the complex valve mechanisms and minimization of carbon creation created by dinosaur oil during the combustion process.

All of the hype about catch cans can be traced to those who sell them and their often lengthy and repetitious infomercials on auto forums. They will often reroute PCV flows just to attach their catch cans which will likely void some of the engine warranty.

The worth of a catch can isn't based solely on the type of vehicle you drive or what size/type of engine it is, it's also directly due to how hard you drive it. If you have a naturally aspirated, port-injected Toyota Corolla that never sees 4000+RPM, a catch can is nearly worthless. If you auto-cross a direct-injected, supercharged Corvette Z06, you'd be VERY foolish not to run a catch can. Here's a few types of vehicles that can benefit from one:

- Turbo/Supercharged vehicles. More cylinder pressure means more oil that will come up through the PCV system. That will coat the insides of the air intake tubing and the intercooler before returning to the crankcase. A catch can prevents this from happening.
- Direct-Injected vehicles. Because the air/fuel mixture never touches the rear of the intake valves, the oil residue can't be burned away.
- High-horsepower V8/V10/V12 engines that are driven hard. More cylinders means more cylinder blow-by means more oil residue. Even with port injection, a catch can is a good idea.
- Diesel engines. Diesels are naturally direct-injected. Although they create less crankcase pressure, catch cans have their worth.

Obviously, there have been many advancements in technology which lessen or eliminate the need for catch cans in some vehicles. You may never have an issue if you own a vehicle with one or more of the above qualities, but having that extra protection isn't going to hurt anything (as long as you remember to empty it every now and then). If you're easily daily-driving your Gen1 RL (total port injection), you have nothing to worry about. As for Gen2's, I believe Honda employs a combination of direct- and port-injection that nearly eliminates the problem of carbon build-up on the intake valves. Someone with more knowledge on them can confirm, but a catch can shouldn't be needed for regular use. If you're drag racing your Gen 2 RL every weekend, well... that's different. And foolish.

Rockwood said:

Cars used short distance clog the pcv. Regardless of engine tech.
Happen on wifey' Volvo driven 4 miles ew daily. Solution is to use it on longer drives in place of my car. That way it heats up and burns off sludge

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Shorter drives are harder on engines for many reasons and this can be one of them. If an engine isn't allowed to fully warm up (allowing the piston rings to expand and seal against the cylinder walls) and is driven at even moderately higher RPMs (above 3000 or so), blow by will be more prevalent and quite a bit of oil can be picked up by the PCV.

I only drive 4 miles to work each way, as well, but I have a 20-mile trip 2-3 times per week to get the truck fully warmed up. My process every time I start the truck is to start it, let it idle for about 20-30 seconds to ensure the oil begins to circulate and then start driving. I don't let it get above 2500RPM or so for at least the first 5 miles of driving on my longer trip days and never above 3000RPM on my short trip days. This is the best balance of getting the truck warmed up as quickly as possible while not taxing the engine too much. Once it's warmed up properly, I let it rip to WOT on the highway at least once a week to "blow out the carbon", if you will.