vented oil fill cap

[Money pit Beretta]

I was looking on another site and the vented cap came up(true topic was extra PCV venting for boost). Thought hey my dipstick keeps popping out of the tube every now and then, so a vented oil fill cap could help(lots of blow-by). Went up to GM and bought two part#12589430. It's listed for use on many engines and the 3400 is one of them. Fit very nice on my 3100 and I can use the other on my Ecotec. Took the old cap downstairs to save it just in case. Now I have three old ones and one can go. Checking the older metal valve covers that are waiting to go on they had a vented cap. Wish I would have known that, it looks like the one that came on the car and the new one has a tab to unscrew it in the middle(and looks cheap).
Anyway just thought I share some pointless info.
Not so pointless, a back up/overflow is not a bad idea for the PCV system.

[1988GTU]

I am not following what you said... can you post up some pictures?

[Money pit Beretta]

They both are the same on top in every way. The one on the left is my 95. The inside is hollow.

[Money pit Beretta]

This is the older one from the metal valve covers. You can see the port on the bottom. The top port is inline with the lower one just under the white flat seal. If you look close you can see a clean spot where it is.

[Money pit Beretta]

This is the new one. Ugly for sure, but it may be the only new one you can get at this time. Please post a link to the old one if you can find it(anybody).

[3X00-Modified]

Just because the inside is hollow doesn't mean its vented... at least I did not think that.

They do not sell the old versions anymore that I can see.... Thats the listed cap for a 96 beretta now on rock auto, or the cheaper Gates ones.

You can order this for an 05 Vette though... It does actually say non vented too... so maybe you are right on that vent deal... I'll have to think about replacing my hunk of an aluminum one for an old vented one to see if it lessens the amout of oil I pull through the PCV and vent system.

[DTMAce]

Just a thought here. If you are having enough blow by to push the dipstick out of the tube, doesn't that indicate a PROBLEM? Like bad rings or something? Just curious.

[3X00-Modified]

That is very true... lol

[wicked-irocz]

I run a fill cap thats vented through a one-way valve so the PCV still functions properly. I wonder if that cap also has a one way valve. Most boosted cars have issues with positive pressure in the crankcase and I'd rather have it over vented than not vented enough.

[Cliff8928]

I run a fill cap thats vented through a one-way valve so the EGR still functions properly.

I'm pretty sure you mean the PCV, right?

[wicked-irocz]

Your right, fixed. Typing what I'm thinking doesn't always work.

[scd88ga]

Just a thought here. If you are having enough blow by to push the dipstick out of the tube, doesn't that indicate a PROBLEM? Like bad rings or something? Just curious.

I thought only haggard turbo DSM's did that!

[Money pit Beretta]

Yeah lots of piston slap when cold. And yes I need a new or newer engine.
Not sure on the one way valve. I'd bet it doesn't have one. Like to dream that it does. Sure would like to have one that has a one way in it.
Oh man you should see what they are thinking about doing to the boosted cars. Multi holes in the valve cover, then to lines that go to a catch can. One guy talked about a vacuum pump with a belt drive. Not putting them down, just trying to say they are going all out.
3X00, that was what I wanted to do. Cut down the amount of oil in the PCV and vent system. And kill off any over pressure(if there is any). Hell the solid trans mount could be shaking it out. I'm not sure and don't want to take any more chances. Changed everything but the front crank sensor and it still idles rough. I'm thinking bad rings or slop in the slapping cylinder.
Sucks to be right on the vented fill cap if it's true. No one will win anything at Bfest with that ugly new cap on(lol).

[Money pit Beretta]

Idle is a bit better on warm up. Feels like it pulls better too. Could be from venting to the outside and not into the cylinders(not sure).