Small filter on oil cap?
Thread Starter
Supporting Vendor
Joined: Jul 2010
Posts: 8,546
Likes: 895
From: Republic of Texas
Small filter on oil cap?
I've seen a few cars that have what looks like a small air filter where the oil cap would go. I'm curious what this is for.
example is on this car:
http://forums.corvetteforum.com/c5-c...-16-800-a.html
example is on this car:
http://forums.corvetteforum.com/c5-c...-16-800-a.html
Team Owner
Joined: May 2001
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From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Sometimes found on blower cars, it's a crankcase filter that's allows air to enter the crankcase preventing pressure buildup.
It's also usually illegal and will not pass a visual emissions inspection in most states since crankcase fumes are open to atmosphere.
It's also usually illegal and will not pass a visual emissions inspection in most states since crankcase fumes are open to atmosphere.
Melting Slicks
Joined: Sep 2006
Posts: 2,736
Likes: 7
From: Redding CA
Just called a simple 'breather'
Burning Brakes
Joined: Mar 2010
Posts: 1,189
Likes: 4
From: Freeport, FL
Mechanically speaking, all pros. (depending on the type, and frequency of cleaning, and oil film or drip may be noticed on the engine though. Keep it clean is all)
Legality speaking - It violates federal emissions law. So, depending on how hard it is to re-install the oil cap before a test, you may not want to try to controversial 'mod'
Personally, I do not trust the effectiveness of the PCV system to properly vent the crankcase so I installed a $10 Mr.Gasket one from Autozone. I clean it every so often and all is well. No more dipstick popping up, and I've noticed less oil consumption between oil changes.
Here's a couple pics:
Legality speaking - It violates federal emissions law. So, depending on how hard it is to re-install the oil cap before a test, you may not want to try to controversial 'mod'
Personally, I do not trust the effectiveness of the PCV system to properly vent the crankcase so I installed a $10 Mr.Gasket one from Autozone. I clean it every so often and all is well. No more dipstick popping up, and I've noticed less oil consumption between oil changes.
Here's a couple pics:
Last edited by manley845; Dec 16, 2010 at 01:34 AM.
Safety Car
Joined: Jul 2004
Posts: 3,904
Likes: 29
From: Vancouver Washington
Another route to go is to run the valve cover line over to a catch can with a breather on it like a Canton Racing Products 23-032PC and you get the best of both worlds. Positive ventilation and no drips on the engine. You're not smog legal, but I'm not telling. 
Team Owner
Joined: May 2001
Posts: 36,836
Likes: 244
From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Since no two engines are identical, each one may have a bit more or less blow-by, which is a function of ring seal plus the amount of boost chosen which will in turn affect any vapor/oiliness issues at the breather cap. Bit of dirt magnet so ongoing attention to cleaning like manley845 said.
The other possible con I've heard is hood clearance, depending on the choice of hood and the particular breather chosen, etc. Seems that one would be fairly easy to solve though.
Give Andy at A&A a call or maybe Chris at ECS as these guys are a couple of the blower gurus on the boards and have probably seen it all at one time or another regarding blower cars.
How you liking your new huffer George?
The other possible con I've heard is hood clearance, depending on the choice of hood and the particular breather chosen, etc. Seems that one would be fairly easy to solve though.
Give Andy at A&A a call or maybe Chris at ECS as these guys are a couple of the blower gurus on the boards and have probably seen it all at one time or another regarding blower cars.
How you liking your new huffer George?
Thread Starter
Supporting Vendor
Joined: Jul 2010
Posts: 8,546
Likes: 895
From: Republic of Texas
Since no two engines are identical, each one may have a bit more or less blow-by, which is a function of ring seal plus the amount of boost chosen which will in turn affect any vapor/oiliness issues at the breather cap. Bit of dirt magnet so ongoing attention to cleaning like manley845 said.
The other possible con I've heard is hood clearance, depending on the choice of hood and the particular breather chosen, etc. Seems that one would be fairly easy to solve though.
Give Andy at A&A a call or maybe Chris at ECS as these guys are a couple of the blower gurus on the boards and have probably seen it all at one time or another regarding blower cars.
How you liking your new huffer George?
The other possible con I've heard is hood clearance, depending on the choice of hood and the particular breather chosen, etc. Seems that one would be fairly easy to solve though.
Give Andy at A&A a call or maybe Chris at ECS as these guys are a couple of the blower gurus on the boards and have probably seen it all at one time or another regarding blower cars.
How you liking your new huffer George?
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From: Providing the most proven supercharger kits for your C5/6/7 609-752-0321
Here is a link to our breather caps, one of the main differences between ours and one of the cheapies is that we have an oil seperator in the cap and the filter. It keeps the cap from dripping oil, even on cars with a lot of blow by. 
http://www.eastcoastsupercharging.co..._breather.html
http://www.eastcoastsupercharging.co..._breather.html
Burning Brakes
Joined: Jul 2007
Posts: 864
Likes: 2
From: Jax FL
Mechanically speaking, all pros. (depending on the type, and frequency of cleaning, and oil film or drip may be noticed on the engine though. Keep it clean is all)
Legality speaking - It violates federal emissions law. So, depending on how hard it is to re-install the oil cap before a test, you may not want to try to controversial 'mod'
Personally, I do not trust the effectiveness of the PCV system to properly vent the crankcase so I installed a $10 Mr.Gasket one from Autozone. I clean it every so often and all is well. No more dipstick popping up, and I've noticed less oil consumption between oil changes.
Here's a couple pics:
Legality speaking - It violates federal emissions law. So, depending on how hard it is to re-install the oil cap before a test, you may not want to try to controversial 'mod'
Personally, I do not trust the effectiveness of the PCV system to properly vent the crankcase so I installed a $10 Mr.Gasket one from Autozone. I clean it every so often and all is well. No more dipstick popping up, and I've noticed less oil consumption between oil changes.
Here's a couple pics:
What did you have to do to make fit the oil fill cap?
Or does it come ready to screw in?Thanks
Burning Brakes
Joined: Mar 2010
Posts: 1,189
Likes: 4
From: Freeport, FL
I have had it in for more than 15k hard miles over the last several months and have had no oil drips or issues with it staying in place. I have only cleaned it twice, but only because I was changing the oil, not because it needed it.
This is not something I would suggest to a person that needs to have a "set it and forget it" mod. Only because I could see someone else being uncomfortable with the method of install.
I did look at the link in post #11 and that would be a nice item to install and not worry about. For me though, it looks a lil ghetto having a hole drilled in the top of a oil cap and shoving in a breather. Not to say that mine is done right, but other than removing it or me telling how it is installed, it looks like it belongs there.
Tech Contributor
Joined: Jan 2007
Posts: 19,397
Likes: 1,137
From: Dyer, IN
While I do think you have a tasteful and cleaning looking engine compartment, there isn't anything about that breather...that looks like "it belongs" there.......and if your sig is accurate concerning your mods, it is not even necessary.
Burning Brakes
Joined: Mar 2010
Posts: 1,189
Likes: 4
From: Freeport, FL
Eh, neither came from the factory, so neither "belong" there.
But I do prefer the looks of my cheapie one. I did almost make one like the one offered in the link in post #11, but I just don't like that look.
I have seen a very nice looking thread-in model for GM engines, but it looks similar to mine once installed and costs about $70. I don't mind spending money, but I don't wanna pay more money for the same darn thing. Case in point, that breather offered in post #11 can be made for less than $10 if you use you old oil cap, so why pay $60 for someone elses?
As far as being necessary, no car NEEDS to have crankcase pressure vented. The engine will find it's own means to vent, just as they did decades ago. However, giving an engine an ample means to vent or better yet installing a source of vaccuum is simply going to reduce blow-by and seal leaks. For me, a $10 breather is worth the added breathing capablilities, should the engine require it. If the engine does not require the added breathing, then I have not lost anything. And frankly, if someone is worried about $10 or even $100 bucks then they might need a better job.
Tech Contributor
Joined: Jan 2007
Posts: 19,397
Likes: 1,137
From: Dyer, IN
Ah, no......because my setup works, and more importantly, it's actually needed, not just for show...
Really? And without a means to vent, where does said pressure go ? Out the oil seals? Perhaps you are too young to remember GM engines with vented oil caps on the valve covers....."decades ago"....
Perhaps you are too young to remember GM engines with vented oil caps on the valve covers....."decades ago"....