oil leaking from breather

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Shmaako

Shmaako

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I am having a fair amount of oil leaking from my drivers side breather. I have a breather on each of my Mopar Performance valve covers on my 383 with a Holley sniper system. The engine has just been through its first summer and while it ran well, I have had a fair amount of oil leaking issues. Valve covers at first were a bear to seal up. I added the breathers by drilling out the valve covers assuming I had too much pressure? Now oil leaks out pretty good. Wondering if I should use a catch can or something?
 
2 breathers? there is your possible issue. Make one of those breathers a hose to the low pressure air cleaner. You need forced circulation (can I call it positive crankcase ventilation?) in there to rid the oil of acids and prevent coking. You can even run a standard PCV valve as it does nothing at idle and nothing at WOT, only venting during part throttle cruise or a header evac. If you choose the evac, run it through a catch can to lessen a black film all over the rear of the car.
 
You guys are on it. PCV in one cover. breather in the other. Air in the breather on one side, out through the pcv to the carb on the other. Make sure there are baffles in the covers under the breather and PCV to keep the oil from splashing up into the two. If that doesn't tke care of the issue you may have bigger problems like too much blow-by. Cross that bridge when you come to it.
 
Simple stuff here that hot Rod folks often overlook! You want a leak free engine! Then Pay attention!

Baffles are the first concern!

PCV's are, well, or can be a bit hard to figure out. It sometimes takes a bit of experimenting to find the right one to get the best balance!

They work really well when configured for the application. Fortunately they are fairly cheap to experiment with!

Unless you are running a full out open race setup with evac drops to the headers you absolutely need one! JMO!
 
Excessive oil leakage can be caused by 'blow by'.

Recent rebuild?

If so,your rings may not have seated properly or something related may not be right.

Try a compression test?
 
I've posted this a hundred times and it never sinks in. PCV on one side, breather on the other WITH a hose connecting to the air cleaner. Here is a diagram of a complete PCV system. That's what you need.
PCV SYSTEM.jpg
 
RustyRatRod said:
I've posted this a hundred times and it never sinks in. PCV on one side, breather on the other WITH a hose connecting to the air cleaner. Here is a diagram of a complete PCV system. That's what you need.
View attachment 1715812371
Click to expand...
:thumbsup: they don't realize a PCV system helps maintain ring seal.
Prepare to post the diagram another hundred times over the next 10 years. Thank you for your effort.
 
fishmens67 said:
:thumbsup: they don't realize a PCV system helps maintain ring seal.
Prepare to post the diagram another hundred times over the next 10 years. Thank you for your effort.
Click to expand...
A lot of people argue that point, but it's a fact. Those people argue all the PCV system is, is emissions equipment. Although that's one thing it does do, it has the benefits of controlling blowby, helping ring seal and keeping the engine clean from oil vapors! What's not to love?
 
I was getting oil out the PCV grommet and around the valve covers On my new 5.9 build. I had a PCV but only used an open breather on the opposite side.

Changed to a breather with a hose running to the air cleaner assembly and BAM, no more oil problems!! Couldn't believe how much difference it made.
 
66fyssh said:
I was getting oil out the PCV grommet and around the valve covers On my new 5.9 build. I had a PCV but only used an open breather on the opposite side.

Changed to a breather with a hose running to the air cleaner assembly and BAM, no more oil problems!! Couldn't believe how much difference it made.
Click to expand...
Yup, you only had "half" of the PCV system. Not many people listen, but you do!
 
RustyRatRod said:
Yup, you only had "half" of the PCV system. Not many people listen, but you do!
Click to expand...
So, a breather, on each side, isn't good ? That's all I have... and I don't have an air cleaner w/ a hose nipped. I did have a pvc, from the carb base, then going to the power booster.. removed that, and did a breather, oil fill is a breather too....
 
Ironracer said:
So, a breather, on each side, isn't good ? That's all I have... and I don't have an air cleaner w/ a hose nipped. I did have a pvc, from the carb base, then going to the power booster.. removed that, and did a breather, oil fill is a breather too....
Click to expand...
No. Breather on one side with a hose hooked to the air cleaner and PCV on the other. Like this.....
PCV SYSTEM.jpg
 
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