Introduction: Creating a Breather Line for Honda Civic 1999 Valve Cover.

Picture of Creating a Breather Line for Honda Civic 1999 Valve Cover.

Ever since I used a warm air intake in my car, the valve cover I let breathe via an independent air filter. In my quest for improved fuel economy, which is damn amazing thus far, I want the valve cover breathing via the engine air filter as per the original honda design.

Here is how I modified my spare cone filter to accept a breather line. The tools are;
-cone air filter.
-drill bits.
-cordless drill.
-clear pvc tubing 1/4inch OD.

Step 1: Fitting in the Breather Line.

Picture of Fitting in the Breather Line.

Drilling a pilot hole followed by the final bit size, I made an entry at the base of the cone filter. I made sure to shake out all the metallic pieces from inside the cone.

I wanted the tube very snug into the hole to have an airtight seal.

Step 2: Adding to the Engine.

Picture of Adding to the Engine.

I popped off the existing cone filter and fitted the modified one in its place. I also removed the air filter for the valve cover. Once the modified cone filter was installed I used a length of silicone tubing to join the pvc tubing to the valve cover.

Step 3: Completion!

Picture of Completion!

I started the engine and it ran well! The idle rpm was a little higher from this modification and I'm very happy about that. Hopefully my fuel economy can improve a bit in time.


pumpdatbass (author)2017-01-06

higher idle = lower mpg at rest, though you may never notice the difference. that extra 1-200rpms is nice though during winter!

Mjtrinihobby (author)pumpdatbass2017-01-06


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Bio: As of April 2017 I have decided to no longer post on instructables. The fact that several of my published works have been removed without ... More »
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