TOPIC: Please explain the T-Line and PCV Valve and how...

to make it. I'm getting very excited for my tax refund although most of it will go paying off debt and saving up money for our son Liam. I finally get the chance to take off the intake manifold and access the PCV Valve. Since I'm a big time Reddit user please "explain it like I'm five".

Please explain the materials that I will need to buy and what tools I will need to use. I like to figure things out on my own as much as I can. Unless if I don't have the special tools I will get a mechanic to do it.But it seems I won't be needing any special tools. I know I can do this. Also is this a more optional or a requirement for all vehicles?

I would love to have my emissions almost be zero and seeing the looks of the safety/emissions technician. Which brings up another point. Has anyone gotten weird looks or said something funny to you when you went to get your safety and emissions done?

Thank you.

?? Hi Juan, I think you need to re-state what you are asking help for. T line? what's that? Scratching my head here...

Tracy G

I got this picture from another user in the forum. Here is the link I got this from. I had to borrow it. I got from the user jv.



This picture is what I'm referring to. I am just wondering if I have to do this for my vehicle as well?

Also I am very confused on the whole catch can and the air/oil separator. Are they different or are they the same thing? What determines that you need to use a catch can or a AOS on a vehicle? I am recommending the Gadgetman Groove to close friends and family. Because I !00% believe in it and want to save my family and friends some money and help the environment as well. I just don't want their vehicles to leak oil and make a mess.

Hey there Juan,

I attached a photo of how I set up my PCV lines to help clarify.





It's easy, just might take some time finding a matching 'T' connector and possibly new hoses.

My advice is, go to an auto parts store. While in their parking lot, unattach your hoses and carefully look at or measure the inner diameter of the hoses. You want to make sure that whatever 'T' connector you purchase will fit snugly into them.

In my case, I had to buy some new hose to fit the 'T' because my existing PCV passive hose was too big on the inner diameter. Since I was working right there, I conveniently went back in the store to get the proper items. I didn't leave the parking lot until I completed the job. Any questions can be answered by the store workers.

The only tools I needed were:
- Vacuum Caps to cap off the PCV port at the manifold
- Knife to cut hose to proper lengths
- Pliers to assist in taking off stubborn existing hoses
- thin Rope w/ knot tied at one end to pull gunk out of the PCV passive tube
- some Muscle, Trial & Error and Patience

As for the catch-can/oil air separator, it's not necessary but is probably a good idea to help keep the engine internals cleaner as well as lower the pollution a bit more.
I have yet to install one, so I can't offer much help on that.

By reRouting the PCV lines into the Fresh Air Intake(prior to the Throttle Body), you eliminate oil spills. What little oil makes it's way back into the Intake Manifold gets burned up or recycled. Which is what happens normally anyways.

Hi Juan, JV has it right and explained it well.

I named the homebuilt Catch-can and the Air-Oil Separator to help clarify what the parts/pieces actually are and how they might be accurately described.

Both do the same thing-divert and capture crankcase oil/vapors and water condensation. Either setup can work. I just wanted to show options as I found them.

You could do your PCV re-route like JV did, then keep an eye on the air duct and TB to see if much crap is starting to show up. Some cars will get more than others, so some might need this type setup others not.

But you did see that JV decided to clean out his PCV hose, there was crap in there!

Far as I know ALL engines or at least nearly all are sucking this crap back in due to the nature of PCV systems.

Another Idea is to increase internal diameter (ID) and legnth of PCV hose using appropriate hose adaptors/connectors. You just graft in this bigger hose onto the existing PCV hose,
extending it. Then route it around the engine avoiding hot sharp or moving things, and keeping hose bends gradual. You then route the new bigger longer hose to the Tee into the passive Breather hose.

This increases internal air volume of the hose and slows the velocity of the flow through it. Try using 5/8' or 3/4" ID heater hose its pretty cheap. Check/ clean this hose out now and then.

This bigger hose is an option for engines that don't spew out much crap in PCV hose. ON my Subaru I use 2 types of AOS's of Euro. origin, with the PCV hose extended around my spare tire almost 7 ft. long! Because my Subie seems to generate a lot of water condensation from crankcase this winter. The condensation will slow down a lot when warm weather returns.

Hope this helps.

Tracy G

Thank you both JV and Tracy. I plan doing this set up on both my Mazda and the Corvette I have talked about. @Tracy I thought this setup is set it and forget it type thing? I am hoping I won't need to clean it out because my PCV valve is underneath the intake manifold so it's a hassle to get to and more money out of my pocket. I'm hoping not to have it cleaned for my vehicle and the Corvette as well. I'm hoping you can tell me that I can avoid cleaning it. I'm very excited because I finally found the solution to the oil leak problem the Corvette was having when the PCV valve was capped
Still got a question though. On most vehicles will I have to do this connection to the air intake? I hope not. I just like capping the intake manifold vacuum port and the PCV valve

Juan Reyes wrote: .... I'm very excited because I finally found the solution to the oil leak problem the Corvette was having when the PCV valve was capped.
.... I just like capping the intake manifold vacuum port and the PCV valve

I was confused by things I heard concerning the PCV system as well.

Correct me anybody if I'm wrong but, You do NOT ever want to cap off or plug up the actual PCV valve itself or it's hose! That will hinder built up engine pressure from escaping, leading possibly to blown gaskets and ultimately oil leaks!

Here is my reason for my statements:
Watch this short video explaining the problem of an inproper modification to the PCV system.

PCV System (Part 6) - Symptoms of a MIssing or Defective PCV System



What is needed is to have the port at the Intake Manifold capped off/plugged!
Because THIS is the critical area that NEEDS to have the best possible vacuum.

By reRouting the PCV hose from the Manifold to a location BEFORE the Throttle Body, you solve the vacuum issue AS WELL AS keeping a functioning PCV system in tact.

Please Stop me anybody if I'm wrong as I don't consider myself an expert! I'd like full confirmation for myself as well.

Sorry that was what I meant the intake manifold vacuum port capped

I have a question. Yeah sorry I'm full of questions. Is this required on all vehicles or just most of them?

How will I know that I need to do this instead of capping the vacuum port on the intake manifold and capping that end of the PCV Valve instead of making a T-line connection to the dynamic and passive PCV ports?

I'm asking because real soon I will be taking off the intake manifold on my Mazda Tribute to access the PCV Valve.

THANK YOU TRACY AND JV FOR POSTING YOUR REPLY ON THIS FORUM POST. Sorry to yell. But light bulbs just went on inside my head. It was like a mini Las Vegas inside my head just at this moment. After looking over this setup. It all makes sense. Now I hope O'Reilly Auto Parts or Auto Zone has both the hoses and the T connector I need.

Now when I walk into the store. Do I just ask if they have a T connector or is it called something different?

I don't recall exactly what it is called, 'T' connector or 'Y' connector; but, if you explain to them that you want to connect 3 hoses together, they'll likely know exactly what to show you. I like to use brass connectors because they tend to have a larger inner diameter which means less restriction, and of course they're way tougher than the typical plastic ones.

The main thing is to figure out what diameter hose you need.
In my experiences thus far, the breather hose has often been of a larger diameter than the PCV hose, so I just go with a hose that fits the majority of ports, and then really struggle to fit the hose onto the breather port.

The reason for this is because(in my experience) 'T' connectors tend to have the same size hose barbs on all 3 ends(unless they are the tiny ones). So a compromise might need to be made.

I try to work on my hose setups right in the parking lot of an auto store, that way I can simply get what ever part I need, on the fly, because you never quite know what you're in for until you start!

I just thought I'd throw some more in here...

Juan just ask/look for vacuum tee's or hose Tee's that's what they're called.

BTW, Juan I just finally spoke to Rob about his 'Vette, he's sending pics and I'm gonna analyze his setup. now I'm still not exactly sure how his hose system is setup--but I ask you to, while I work on this one to see what ideas you come up with on your own, then we can compare notes on this one soon, OK?

I keep a collection of vacuum tee's in bags/drawers, along with tons of caps. you can find both metal and plastic tee's at auto parts AND hardware stores. I don't know how many times I've been at home despot or lowe's pawing around in the Irrigation aisle fondling the different tee's and fittings. No one store of any type has it all, gotta keep on the lookout always... I did carb. rebuilds for years so I have more than most shops ever will...

Re: the whole PCV re-route/ breather hose gig: many vehicles it's easy, you just cap man. vac. port and re-route the PCV hose as needed, might be just one tee needed. Others are more involved.

The ones where oil is sucking into the breather hose after re-route, OR if water vapor /oil make the Milkshake goo, well to me that's one that NEEDS an AOS installed inline in the hose someplace.

I've already shown how/what my ideas for this are, just look in Index--Service Bulletins---Home Made Breather Catch Can, and Air Oil Separator. Or just use the search function on here and go from there!

One last thing: The Problem Ones w/ oil/goo in the breather hose--another idea is to increase the volume of air in the hose. Use larger inside diameter hose, and legnthen if possible. The crankcase will vent/breathe just fine, but airspeed/suction inside the hose will drop. To adapt to larger ID hose, either look for hose adaptors where you find the other tees/fittings, or often you can just push a bigger hose over smaller one, and use a hose clamp over the junction. Adaptors are better, hose-in-a-hose works too. You want a tight connection, loose won't cut it.

Tracy G

By capping the PCV port AND the PCV valve, you will force more air through the breather hose, thereby reducing the build-up of that ugly chocolate shake mix...

Something to think about.

Ron