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Discussion Starter #1
Hi all,

I'm losing oil out of my breather cap (I have one of those stand-a-lone push in chrome breathers).

My valve cover is just covered in oil to the point that it's running over the back of the engine and transmission. If I clean off the valve cover and go for a drive, it'll be covered in oil again. Nothing comes out while it's just idling in the drive way, so it's not just a regular leak.

I replaced the gasket and breather, thinking it was a bad gasket, but after putting on a fresh gasket and breather, I drove to the corner and back and it was enough to already cover the valve cover again.

My PCV valve works, it's hooked up to direct manifold vacuum. I don't have oil coming out of my dipstick tube, etc. Not sure what else to do. My engine's a mess and I keep having to top the oil off.

Thanks for any advice.
 

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Discussion Starter #2
I forgot to mention my compression, which was around 150 for all six cylinders on the last test.

After reading through your writeup on the PCV system (thanks for that), I don't see how mine would be hooked up incorrectly and is how I understood the PCV system to work. I have a breather cap on one end of the valve cover. This is an aftermarket press-in breather, (as the engine is far from stock).
On the other end of the valve cover is the grommet and PCV valve, which is connected to a vacuum hose to the intake.

As the intake pulls air/vapors out of the valve cover through the PCV valve, fresh air is filtered through the breather cap as it is pulled into the engine. It's the same setup I've had on the engine for several years and is how I have it hooked up on my other 300 as well.


The only part of the system that I don't know anything about is the oil separator chamber. I imagine it's good because when I remove my carburetor, the intake bores are shiny aluminum clean. I imagine they'd be oily if this was bad? I also don't know if that a failure of that system would make oil come out the breather.
 

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are you using the stock valve cover?
is the baffle still in the valve cover?

I would make sure the pvc is getting good vacuum?

sounds like a blow by issue, how many miles on engine

does your oil cap have a oil separator baffle in it?
where does engine get fresh air from that the pcv is evacuating?
 

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Discussion Starter #4
This is a used engine with unknown miles that I put in a few years back. Drives great, pulls hard. Good compression. I really don't recall having this issue when I first put it in, so I think it developed only a little while back. I can't recall for certain though.

I have an engine from an '86 in there right now, and the valve cover is stock to the engine. This particular valve cover has 3 holes in it. The PCV on one end, and the oil cap and breather (which are separate) on the other.

Here's a picture:



Fresh air comes from the push-in chrome breather.


-
 

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Seems like as vacuum is not enough. Is vacuum hose from PCV clean and not clogged?

1. If you just open oil filler at idle, what direction of flow will be? From cover or into cover? Put a sheet of paper on opened filler or just close it by hand....
2. What will happen at high engine speed in same conditions? If you describe that it can be in short time, you can simple to modeling this situation without real moving.
3. You changed press-in breather and seal - but check other - what is under breather hole, under the cover in this place, is it not clogged? IDK, but maybe something (dirt) stuck between separator baffle and breather hole?
 

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Discussion Starter #6
Thanks for the ideas. I've had a few on this site and another suggest that maybe the vacuum isn't strong enough. I'll check to be sure nothing's clogged and I have good air flow.
 

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Roller rockers are gay
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My friends 79 with a 400M engine is set up the same way. One cover has a PCV and a hose, the other valve cover has a breather like yours. It doesn't blow oil out, it doesn't blow out gaskets, and it doesn't burn any oil.
 

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Has anyone else noticed the PCV hose is flattened right before the PCV valve?
IMO a new pcv line and PCV valve is in order.
 

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Discussion Starter #10
You're correct. It was getting a little soft right at the end, so I cut it off and shortened it up. The rest of the hose was firm and fresh though. Not sure what was up with the last two inches.

I know none of that sounded appropriate. :toothless
 

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Roller rockers are gay
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Out of context, that would sound weird. :toothless

You deal with soft hose regularly? :goodfinge
 

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also it could be collapsing your vacuum tube running to your pcv, make sure it's strong enough that the resistance from the valve mixed with the vacuum of the intake isn't just sucking it shut.
Beyond that, I'd say you have excessive pressure in the upper valve train and probably quite a bit of blow by. My 70 mustang I used to have had one of the K&N breathers on it and that thing spewed oil mist out of it any time it got hot.. can't say for sure what was wrong because I sold it before I found out the hard way.
 

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Discussion Starter #13

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Discussion Starter #14
Yeah, I wasn't paying enough attention. :brownbag Since most people have V8s, I assumed yours was, too. :doh0715: I totally ignored your sig pic. :wowcb:Great, but are you sure you have the PCV in the correct port? It's been so long since mine was carb that I don't remember where it belongs.

Have you ever done an engine flush? Have you ever pulled the valve cover & inspected/cleared the drainback holes in the head? If they sludge up, oil will accumulate in the valve cover, and eventually slosh into the hoses.
http://www.supermotors.net/registry/media/929383
http://www.supermotors.net/registry/media/72461
I recommend Berryman B-12 pour-in for flushing crankcases & fuel systems. But you need to be prepared to change the oil and filter several times, depending on what comes out with the first flush.
No worries. I can definitely see how it'd be a bigger issue on a V8. Sounds like a bit more complicated of a setup.
All of my sixes have had the PCV valve on the back of the valve cover with the oil cap on the front. This is the first one that's had a dedicated oil breather and a cap (usually integrated). However, it's the newest valve cover I've had, so I would think the setup would be the most ideal. Dunno.



I haven't done an engine flush, but what you say mirrors a few things I've read on line about plugged drainback holes. That would make sense.

I think first I'll clean out my vacuum ports to be sure there's nothing reducing flow and put on a new hose, and see if that takes care of things. Even though I trimmed the end, the hose seems to be a bit mushy.

Then try a good flush. Who knows how long it sat before I picked it up.
 

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make sure you get proper hose,regular vacuum hose is not compatible with pcv systems, the oil softens the rubber

get some designed for pcv systems
 

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Discussion Starter #16
Good to know, I didn't know there was a difference.
 

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depends on manufacturer

if you cant find any pcv compatible hose, trans hose(a bit stiff though) will work

also a local hydraulic shop can supply you with a push loc type of hose in many diameters (and colours) that is sturdy enough not to collapse and is oil rated
 

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Any 'Gates' hoses, with oil-proofing and fits with diameters...
 
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