On the stock PCV setup there is a PCV valve in the passenger side valve cover connected to a hose from the intake and a breather hose going from the drivers side valve cover to the air box on my '90 5.0.

What I'm wondering is would it be ok to put a vacuum hose on both valve covers? I'd like to gut out the pcv valve on the passenger side to basically make it an elbow fitting and run the breather hose straight to the intake. Would this work? I would like to do this as I read that a sealed crankcase with a positive vacuum is much less susceptible to oil leaks.

 

That is not your PCV valve running to the air box. On the 4.9 there is a PCV valve on the back of the engine with a hose running to the engine. The one running to your air box is just a breather for crankcase fumes. Our truck has both a breather and a PCV valve. The stock replacement for this breather is right here. http://m.advanceautoparts.com/mt/sho...n_jtt_redirect



Edit: sorry it's early for me lol. I just now correctly read what you wrote. If you get a breather filter like this one I linked and hook it straight to the intake it should work fine. Sorry once again.

 

No problem Ol'Navy thanks for the link. So it would be ok to have a vacuum source on both valve covers? I've researched this and some say it wouldn't be good since the crankcase has to have fresh air

 

Ok, you're overthinking this waaaaaay too much.

Oil leaks occur as a result of either old parts (cork gaskets anyone?) or a lack of oil changes, which causes gaskets to dry out and crack.

Leave your PCV system as is.

If you get into adding boost to your truck, redoing the PCV system might be necessary, but for a naturally aspirated system, it's a waste of time and energy.....and dollars.

 

If it ain't broke...... Don't waste your time. It's fine the way it is

 

Alright guys. I'll leave it stock. I have read even more into it and %99 of people agree that one pcv is good.

However, what is your opinion on a valve cover breather filter vs. a hose to the air box? I think I'll leave that part stock as well. I've read that at WOT there is no vacuum in the intake so the pcv is not sucking up the blow by gasses but instead they flow out the breather hose into the air box. Also when the blow by gas becomes too much for the PCV to handle (like on an older high mileage engine) some is sucked up but most of it flows out the breather tube into the air box. Does this sound correct?

 

Yes it does. I just went with a breather filter but you may have to clean it every few weeks or so.

 

I have a breather filter also. No Negative effects after four years. Only reason I did it is because the factory breather tube was damaged and that was an easy fix

 

There is a stock breather filter that goes on the end of the that hose on the inside of the air filter box under the air filter. Most of the time, people never bother to replace it, so it disintegrates and all you see is the plastic part on the inside of the air filter box and it becomes very easy to miss.

Honestly, put a new stock replacement breather filter (even a generic store brand one is sufficient) on it and call it a day. Your PCV system in its entirety doesn't need any modifications.

Save those dollars for your engine build and buy a nice SD friendly cam.

 

I've seen those stock pcv filters, I replaced mine and my old engine soaked it in oil after about two drives! But I'm sure with a reman engine it won't have near as much blow by as my old one, so a entirely stock pcv should work fine. I'll probably stick a breather filter on after I install a "warm air" intake like Ol'Navy's.