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Old 11-08-2012, 09:11 PM   #1
Scooby Newbie
Member#: 307851
Join Date: Jan 2012
Chapter/Region: NWIC
Location: Seattle, WA
2005 Outback Sport

Question Seafoam/CEL Help

Hi guys, first post here, so go easy please. I have a '05 Outback Sport with a '05 RS engine swapped in. 85k on body, 56k on engine.

I had my check engine light come on the other day. Swung by O'Reillys to get ECU read. pulled a code for "Catalyst System Efficiency Below Threshold" (p04290). I've been told the CEL comes on when emissions is running at/below 95% efficiency. The guy at O'Reillys suggested running Seafoam since the age of the engine indicates that it's probably just gunked up, not requiring any replacements, and that I could just clear the code and see if it comes back. I got a can while I was there because I had planned to do seafoam regardless. Here are my questions:

1. Is seafoam a reasonable thing to try given my circumstances?
2. if so, should I just use the gas tank method, or feed the seafoam through a vacuum line as well?
3. here's where my noobness kicks in: I don't have an idea of which vacuum line to feed the seafoam through, nor where I would find any particular one. I've watched a few youtube videos but they are all for turbo models. It's dark now, but if it helps, I will post a photo of my engine tomorrow morning.

Thanks in advance guys.
snakesandarrows is offline   Reply With Quote
Old 11-09-2012, 11:01 PM   #2
Scooby Newbie
Member#: 307851
Join Date: Jan 2012
Chapter/Region: NWIC
Location: Seattle, WA
2005 Outback Sport


bump. anyone?
snakesandarrows is offline   Reply With Quote
Old 11-10-2012, 10:06 AM   #3
Scooby Guru
Member#: 70395
Join Date: Sep 2004
Chapter/Region: MAIC
Location: Da-boonies,Va

If you would have typed "seafoam" in the search button you would have had your answer in minutes. Pretty much every internet forum has one. Use the BPV hose. STP and CRC both now make something similar to Seafoam but slightly cheaper.

quazimoto is offline   Reply With Quote
Old 11-14-2012, 02:49 PM   #4
Scooby Newbie
Member#: 219717
Join Date: Aug 2009
Chapter/Region: South East
Location: Milton, Florida
05 FXT Dom2.5R
4EAT FTW!!!!


He doesn't have a BPV hose, he's NA.
1. It is worth a try. It may or may not work, but either way should be good for your engine.
2. I usually do both methods.
3. I have seen people use the Brake booster hose, but whichever one you use, make sure it is close to the center so that the seafoam goes into all cylinders. On your car you can acctually run a hose directly into the throttle body by loosening the intake and sliding it inbetween. Don't take the intake off completely because it will through the MAF completely.
gutie04 is offline   Reply With Quote
Old 11-15-2012, 12:36 PM   #5
Scooby Specialist
Member#: 111565
Join Date: Apr 2006
Chapter/Region: W. Canada
Location: Winnipeg
1999 Legacy 2.5GT
2007 Legacy GT Spec-B


Most NA guys tend to just use the PCV tube when Seafoaming. Depending on how your intake manifold is set up may only be cleaning 1 cylinder if you use the brake booster hose. Some (if not most) Subaru intake manifolds have the brake booster hose tapped into the #4 runners.
V8Slayer is offline   Reply With Quote
Old 11-15-2012, 01:13 PM   #6
Scooby Specialist
Member#: 267815
Join Date: Dec 2010
Location: Workn on my LSX swap
Be in awe
dont hate .)


You needs cats homes
Thats what the code indicates..........seafoam aint gonna help the cats release oxygen
Paidfor is offline   Reply With Quote

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