Piston Slap: For a Cleaner EcoBoost, Install a Catch Can?

Sajeev Mehta
by Sajeev Mehta
piston slap for a cleaner ecoboost install a catch can

Mark writes:


I’ve had my 2015 Focus ST for 15 months and 14,000 trouble-free miles so far, and I’m really enjoying the car. The car is still 100 percent stock, but I’ll likely contact Torrie for a tune before long.

As much as I like the car, I’m really alarmed to read about the intake valve “gunk” issues with Ecoboost and other direct-injection engines. It seems as if DI engines have a real problem that the manufacturers really aren’t willing to acknowledge or address (if it even can be addressed).

What’s your opinion on oil separators and/or catch cans? Are they a good preventive measure, or should I just resign myself to funding a cleaning via walnut shells or other similar clean-up tactics when gas mileage starts to dip, power drops, or misfires develop?

Some of the more basic oil separators, such as one from Steeda, cost $65-80, while more elaborate catch cans run $200 or more, plus installation. At that higher price, spraying in a can of CRC’s Intake Valve Cleaner now and then and just paying for a cleaning at some point down the road might not be such a bad choice.

What would you say is the most cost-effective choice for someone like me, who plans to keep the car for probably 80,000–100,000 miles, but probably no longer than that?

Sajeev answers:

The ideal fix is a piggyback port fuel injection system. Toyota’s been at it for a while, with no internet chatter about walnut shell blasting. Since that ain’t happening on your motor (it’s going down on the soon-to-be released 4.8-liter V8), and because it’s turbocharged, consider installing a catch can as preventative maintenance.

Of course, that depends on the application. With a stock tune? Probably not. But after adding more-than-stock boost (via tune, bigger turbos, etc), consider it a mandatory upgrade. Catch cans are simple, cheap (but YGWYPF) and easy to remove/sell if returning to stock for resale purposes — which is highly recommended to claw back extra cash you won’t see otherwise!

What say you, Best and Brightest?

[Image: Shutterstock user Creations]

Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.

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3 of 49 comments
  • Shedkept Shedkept on Dec 28, 2016

    Porsche has had issues with the SAI (Secondary Air Injectors) on the '96-'98 993 models with OBDII. The '95 can have the problem but there is no "Check Engine Light" since it's OBDI. LOL. DI engines on later models have had issues as well. @sajeev-mehta; I like the Mercury Marauder idea. Cool cars, bullet proof chassis and engine. Police still use the Crown Vic format.

    • Sajeev Mehta Sajeev Mehta on Dec 28, 2016

      Crown Vics are starting to get thin in police fleets in my town...the newest ones are 5 years old now!

  • GeoS GeoS on Dec 28, 2016

    Any comments on using a catch can in cold weather regions? I thought about getting one for my DI engine but it seems they can freeze from moisture and effectively block the PCV function.

  • ToolGuy CXXVIII comments?!?
  • ToolGuy I did truck things with my truck this past week, twenty-odd miles from home (farther than usual). Recall that the interior bed space of my (modified) truck is 98" x 74". On the ride home yesterday the bed carried a 20 foot extension ladder (10 feet long, flagged 14 inches past the rear bumper), two other ladders, a smallish air compressor, a largish shop vac, three large bins, some materials, some scrap, and a slew of tool cases/bags. It was pretty full, is what I'm saying.The range of the Cybertruck would have been just fine. Nothing I carried had any substantial weight to it, in truck terms. The frunk would have been extremely useful (lock the tool cases there, out of the way of the Bed Stuff, away from prying eyes and grasping fingers -- you say I can charge my cordless tools there? bonus). Stainless steel plus no paint is a plus.Apparently the Cybertruck bed will be 78" long (but over 96" with the tailgate folded down) and 60-65" wide. And then Tesla promises "100 cubic feet of exterior, lockable storage — including the under-bed, frunk and sail pillars." Underbed storage requires the bed to be clear of other stuff, but bottom line everything would have fit, especially when we consider the second row of seats (tools and some materials out of the weather).Some days I was hauling mostly air on one leg of the trip. There were several store runs involved, some for 8-foot stock. One day I bummed a ride in a Roush Mustang. Three separate times other drivers tried to run into my truck (stainless steel panels, yes please). The fuel savings would be large enough for me to notice and to care.TL;DR: This truck would work for me, as a truck. Sample size = 1.
  • Art Vandelay Dodge should bring this back. They could sell it as the classic classic classic model
  • Surferjoe Still have a 2013 RDX, naturally aspirated V6, just can't get behind a 4 banger turbo.Also gloriously absent, ESS, lane departure warnings, etc.
  • ToolGuy Is it a genuine Top Hand? Oh, I forgot, I don't care. 🙂