A Look Inside The Pcv Breather Box

[boxpin]

Question: Should I replace or clean the breather box?

Answer: CLEAN IT, keep your oil clean and you should never have to buy one again.

The breather box separates oil from the crank case and drains it back into the engine while letting excess pressure out of the block. It has been said that you should replace your breather box as part of your maintenance schedule. I have heard that you cannot clean them and must replace them. I am going to show you that you can absolutely clean them and reuse them. A good soaking of carb cleaner and rinse should put you back in business and you can insert cleaning tools if needed, your not going to damage anything.

Here are a series of pictures showing the inside. Bottom line...its hollow.

This last picture is really the only spot you need to put some effort into cleaning. It is the drain line and does turn. As you can see (although the picture is blurry) that its a straight shot to the bottom. You just need to make sure the path is clear.

[Cleven]

NICE POST!!

[prasamin]

WTF is the point if it's hollow?

[troyhyde]

Since I don't desire spending any money I don't need to, I typically blow into the breather box and various hoses for the PCV system. New stuff flows pretty nicely. The old stuff gets crusty buildup in the arteries and won't flow as well. I typically re-use if the flow is good and toss if it appears constricted at all. Sometimes the PCV system looks tragically nasty and ought to be tossed out of general principle.

I was hoping there was a magical dwarf that lived inside the breather box and destroyed fumes with a light saber. Life disappoints once again......

[Dick Dastardly]

I do this too..soak in Throttlebody cleaner and shake while blocking holes. repeat until clean...re-use

[Matty Moo]

I think I've bought 5 of those things so far. Makes me feel like a jackass after seeing this for wasting the cash. BUT, on the plus side I've always skipped the $35 brittle plastic tube and went with $7 worth of copper...so I suppose I'm somewhat even.

[burnout8488]

It's about time someone cut one of these open. I wish there was a way to buy the full PCV kit on FCP minus the breather box. Now we definitely know it's almost always a waste to replace it.

[survolvo]

There is. You order all the parts, minus the breather box.

[Q-Ship]

I think I've bought 5 of those things so far. Makes me feel like a jackass after seeing this for wasting the cash. BUT, on the plus side I've always skipped the $35 brittle plastic tube and went with $7 worth of copper...so I suppose I'm somewhat even.

What size copper did you use?

[cn90]

I recently replaced my factory oil trap (dated 1997 and has 150K on it).

- Here is the inside anatomy. If one is short on budget, give it a good clean with brake cleaner etc.

- Or soak it in gasoline for a few hours (do this outside of the house).

- Then get a small screwdriver to clean all the ports (3 total)..

- Flush it with water.

- It is basically a hollow box, the idea is the oil + blow-by vapor (RED arrows) combo gets inside, the blow-by vapor (GREEN arrow) gets sucked back into the Intake, while the oil (BLUE arrow), being heavier, drains downward.

The bottom line is: if it does not too bad, it can be re-used.

[Yellow95]

I think I've bought 5 of those things so far. Makes me feel like a jackass after seeing this for wasting the cash. BUT, on the plus side I've always skipped the $35 brittle plastic tube and went with $7 worth of copper...so I suppose I'm somewhat even.

What are you using for the connections to the box and to the intake tube with the copper?

[cn90]

In my case, all hoses are Volvo EXCEPT for the vent hose.

I use 5/8" hose that runs from the top of the oil trap to intake elbow.

It costs a few dollars at local auto parts store (instead of $45 for the Volvo crap).

No more smoking dipstick.

[Matty Moo]

What are you using for the connections to the box and to the intake tube with the copper?

I'm using OEM elbows and connectors. The copper has the exact same I. D. as the oem plastic tube. I can't remember the exact size off the top of my head but the only caveat is that you have to be mindful of not kinking the copper when bending it. They have spring benders at the store or you can wrap a rag around the area you are bending.

[cn90]

Factory setup is like this:

- Oil Trap Top Port 5/8" ---> Rubber Elbow (5/8"--->3/8" transition) ---> 3/8" plastic pipe ---> Another Rubber Elbow (3/8"--->5/8" transition) ---> 5/8" connection to Intake.

So you can why I did the mod with 5/8" hose that goes straight from point A to point B, no rubber elbows.

[Keaton85]

I reuse the elbows from the old Volvo hose as they are pretty rugged and clean up just fine. You do have to hammer out the old brittle plastic most times. As for bending the copper, it does take some time but going slowly will prevent it from kinking when you make the 90degree turn.

As for the oil trap, they can be cleaned but some of them are to far gone and/or are so brittle they break apart at the bottom drain. Soaking them in gasoline really works well. BUT if you are in a time crunch and don't have a spare cleaned already, the URO box is well built and cheap. The way the box actually works is the vacuum from the motor sucks in on the nipple at the top of the cylinder that drops down from the middle. The cylinder that is inside of the oil trap actually acts like a divider for the oil to condense onto and then drip back down into the engine. Without getting the oily mist up into the intake.

In my opinion the most important part of this whole system is the vacuum hose that runs from the pass. side of the intake to the PTC nipple. This vacuum hose takes care of pressure during idle when the pressure is actually building and most of use get the "smoking dipstick". Once the throttle opens, the vacuum shifts itself to the port leading into the intake hose right in front of the turbo. The hose size from the trap to the PTC is not as important flow wise, since the opening into the intake tube at the turbo is only about the size of a regular vacuum line, about 5mm-7mm I believe.