Oil coming through breather hose

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On my 2001 Honda Civic, 205k miles, I've noticed that there is oil coming from my valve cover to intake breather hose.

I checked the original PCV, it apeared to be working ok, so I cleaned it and re-installed it.

Is this the reason some ad oil catch cans?

My gas milage has been going down lately, and I'm wordering if this has something to do with it. It's also using oil at about one quart per 5000 miles, and I'm assuming from this reason.

Here's a pic, not my engine, but similar. It's the tube next to the dip stick. Goes from the valve cover to plastic intake.

2532-050-engine-480.jpg
 
Originally Posted By: JakeR22
I checked the original PCV, it apeared to be working ok, so I cleaned it and re-installed it.

Replace it anyway. It's a fairly cheap part, isn't it?

My brother replaces his once a year, IIRC.


Originally Posted By: JakeR22
Is this the reason some ad oil catch cans?

Yes (although the causes are varied).


Originally Posted By: JakeR22
It's also using oil at about one quart per 5000 miles, and I'm assuming from this reason.

Quite possibly.


Hopefully someone with more relevant knowledge will chime in...
 
Remove the intake and look at the Throttle body. If 1 quart per 5k miles was passing the TB it would be coated in oil and carbon. I have been collecting and measuring my PCV output. Its roughly .5oz per 1k miles at the moment with colder weather.

If fuel is getting into the oil that can increase consumption as well.
 
d00df00d:

Gen 7 civic PCV valve is fully metal-bodied it's hard to reach: it's hidden in a baffle chamber behind the enging block, close accessories belt on the right-rear of this picture. Requires a 17mm wrench and nimble fingers to navigate otherwise you may never be able to locate it at all.

I spray-cleaned my dad's PCV once a year. OE Honda charges over 35CAD for a replacement, and no reliable aftermarket ones available to date.

Good news is, it doesn't clog up easily like previous generations of HOnda engines.

Q.
 
Tater;

I did, and it does look black and glossy.

What are you using to catch your PCV output?
 
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I stopped by the home depot and bought a small water separator for airtools and some fittings.

http://www.homedepot.com/webapp/wcs/stor...25X-_-100027474

I already had a length of 5/16 fuel line so I built what I needed from these items. This is a temporary setup since the PCV line was a short L that always had oil. I did have to seal up leaks in the separator since it was leaking like crazy. I have been emptying it weekly since I bought the smallest unit and measureing the output.

Here is your problem as I see it, you are getting oil on the low vacuum side if I understand you correctly. That would mean your system is working backwards since any oil should be flowing out the PCV side to the intake. Are you driving agressively? If so then when the TB is wide open the intake side is high vacuum and can pull vapor up the line to the intake.
 
Originally Posted By: TaterandNoodles
I stopped by the home depot and bought a small water separator for airtools and some fittings.

http://www.homedepot.com/webapp/wcs/stor...25X-_-100027474

I already had a length of 5/16 fuel line so I built what I needed from these items. This is a temporary setup since the PCV line was a short L that always had oil. I did have to seal up leaks in the separator since it was leaking like crazy. I have been emptying it weekly since I bought the smallest unit and measureing the output.

Here is your problem as I see it, you are getting oil on the low vacuum side if I understand you correctly. That would mean your system is working backwards since any oil should be flowing out the PCV side to the intake. Are you driving agressively? If so then when the TB is wide open the intake side is high vacuum and can pull vapor up the line to the intake.


After doing a little more research, I agree, oil should not be going in that direction. My wife usually drives the car, mostly highway miles, and not agressively.

Awhile back a spark plug came apart, and put some pieces in the cylinder. It seems to run fine, I'm thinking it may of damaged a valve seat or something similar, causing excessive blow bye, which may also be the cause of the problem.

Do you have your catch can on the pcv to intake tube, or fresh air to valve cover ?
 
Even if the PCV valve is OK, it can get plugged by moisture freezing . This will also cause PCV vapor backflow and get your symptoms.

A common water separator for air tools works great, esp. on smaller engines.
My advice it to remove the filter, and connect it so the flow is opposite of what the arrows say. It will not plug with frozen moisture this way, and flow is not impeded otherwise.

If the 'O' ring for the reservoir gets lost or broken, you can use teflon tape on the threads, or electrical tape on the outside to seal it again.
 
What if I just plug the hole on the intake. And put a filtered breather on the hose going into the valve cover?

Something like this;

0611_ghtp_57_z+ls1_engine_build+valve_cover_breather.jpg


That way the pcv can still bring in air, but not from the same place the engine brings in air.
 
Originally Posted By: JakeR22

Awhile back a spark plug came apart, and put some pieces in the cylinder. It seems to run fine, I'm thinking it may of damaged a valve seat or something similar, causing excessive blow bye, which may also be the cause of the problem.

Do you have your catch can on the pcv to intake tube, or fresh air to valve cover ?


If you are having excessive blow by then the filter will simply fill with oil and junk from the crankcase. You need to investigate that cylinder for sure. What about a compression check? Check all the cylinders and then add a couple drops of oil and recheck each cylinder. A spark plug falling appart may have scored the inside of the cylinder.

A catch can should be between the PCV valve and the intake manifold. The fresh air side should not have any oil or junk on that side of the system. The sysytem should bring fresh air into the valve cover from before the TB and burnt gases, blow by and a little bit of oil flows out on the PCV side.

A basic PCV valve.

bege001t.gif
 
I don't own a honda, so I am no expert there.....
I did install a catch can on my '96 windstar.
A catch can should be installed in the PCV line......so that the vaccum from the intake draws the crankcase vapors out through the PCV valve......through the catch can....and into the intake.

The FIRST thing that I would recommend that you do, however, is inspect the PCV line.....make sure that it is not broken, pinched or.....(important) not extra soft from age and exposure to oil.......such that it is collapsing under vaccum.
It sounds like your PCV valve is in a hard to see location....which means that some of the line going to it may also be hard to see.
If the line is soft....and collapsing under vaccum.....it will restrict the flow.......worse case....you have no flow.
This could cause a slight pressure condition inside the crankcase....relative to the BREATHER input to the crankcase.....which often is connected to the big hose.... between the throttle body and the air filter.

While the vaccum inside the intake manifold is much higher than the vaccum in the hose that is between the throttle body and the air filter.......The hose between the throttle body and the air filter will be at a greater vaccum than the outside atmosphere.......which if the PCV line is completely blocked (collapsed).......would cause air to flow OUT the breather line to the flex hose between the air filter and the throttle body.

OK.....sorry for the long discussion.......but my point is to inspect....to make sure something simple is not causing the problem.
I am sure that you realize that it is important to remove the crankcase vapors through the PCV system......

Please note that the catch can will collect a LOT of 'stuff' in the cold weather......so don't be alarmed.
Particularly....as I see that you list IL as your location.....and it has been much cooler over the past month.

The idea of a catch can is to provide a dead air space for the oil vapor to fall out.....condense....and collect in a location other than your intake manifold.
The larger the dead air space......the better.
I have a "Greddy" catch can.
I would recommend that you do a internet search on "PCV catch cans" and look at some of the designs available.....I saw a design that uses a stainless steel mesh to create a place for the vapor to condense......collect droplets...which will fall down into the catch can.
I don' want to violate the site rules with links.....and I am not trying to promote any particular brand or product.....just to give you an idea of what you want to acomplish.
My Greddy can does not have the stainless steel mesh......it also cost less than those.....but I can see the advantage of them.....but don't build your own using steel wool or a brillo pad!!!

It is SUPER IMPORTANT that any catch can setup that you design / install does NOT reduce or restrict the flow through the PCV line in any way.

If you make your own PCV catch can with a "water separator for air tools" as recommended.....I would recommend that you REMOVE the little filter thingy that is often inside those....as they can become dirty and clogged....restricting the flow over time.

In any case.....a catch can....whatever system that you come up with will need to be monitored and emptied as needed (MUCH more often in cooler weather).

Another thing that might be possible......maybe vapor is rising through the breather line when the motor is turned OFF?....while the motor is hot......

1 quart in 5000 miles is not a lot of consumption......although I am guessing that you are seeing this as a change.......from what you are used to.
I wonder....is this a constant drop.....or does it drop more as the oil gets more miles on it?
If so....that would indicate that something is causing your oil to break down early (breaking down within 5000 miles is early).
 
Sure - Go ahead.
Most systems will work just fine like that.

The reason factories don't do it that way anymore is simply for containment of any blowby .
 
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You also mention poorer gas mileage.
How is overall performance? When I had my catalytic converter start to plug up, my breather was seeping oil at first, to the point where it eventually was leaving a noticable spot on the air filter (pcv filter was soaked). After that, the cat made itself noticable in performance loss.

Alex.
 
Thanks for all the help and advice.

I'm going to change where fresh air intake and see if that helps.
 
Unless you fix 'whatever', your new little filter will work fine, but it will now leave the oil around itself, in a new spot.
It is not a fix, really. It's just another way of admitting air.

So don't expect miracles from your new part.
 
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