rbaksi

iTrader: (3)

Hello all, I've got a huge oil burning problem that I'm trying to decrease. I just replaced both valve covers due to leaking gaskets and they fit great, no more oil leaks. Before doing this, I would burn maybe a quart every 1500 miles, no its a quart at every fill up 200-300 miles. I'm sure my rings aren't in he most perfect shape (208K).

The intake manifold has tons of oil in it. I installed a catch can PCV>Can>IM and the same amount comes through but the can holds it. I disconnected the tube from the can to the IM, left it open to vent the crankcase, and blocked off the IM port. Now there is barely any oil collected.

My question here is, why do we even need the PCV valve at all on this engine? There is already a breather tube connecting the front valvecover to the intake box. Any pressure needed to vent can go through that.

FanaticMadMax

that hose that you're referring to that's on the front valve cover is not a breather hose, they call it blow by gas hose. It's necessary for PVC on the rear valve for crankcase vapor to go back into the engine. Unfortunately those early 3.5 have those known problem burning oil due to cheap piston rings. only remedy for that possibly re-ring job or a newer engine.

rbaksi

iTrader: (3)

Thanks Fanatic. I've decided to vent the PCV to a catch can and then to atmosphere. It seems to markedly decreased the burning. I capped off the intake manifold port and the idle is much smoother. This will be a solution for now until I get a new car or decide to tackle the rings.

SubwayVQ

IMO, I’d rather have a 5th gen that burns oil than a 6th gen with faulty chain guides.

rbaksi

iTrader: (3)

The chain guides on 5.5s are the same - still suck

Prophecy99

iTrader: (1)

can you please give mroe details on your diagnosis and solution to what you have done with the oil catch can stuff??

i am at 224k, gutted precats a while ago and they were totally intact at 180k, but average burning for age. id love to get into this catch can stuff, but never really heard of a nice one that was a go to for our cars... and if you go outside here theres way too many options to decide.

rodent_infested_03

The catch can lowers consumption how exactly? Have you removed the PCV valve? Maybe the intake air pressure sucks oil out the pcv hose? Trying to think of reasons why disconnecting would change consumption.

SubwayVQ

No, no they aren’t. That’s why you hardly see videos/threads about a 5th gen with a ticking noise.

maxinout93

I agree id rather top off the oil then the have to worry about replacing the engine when the guides fail on the 6th gen.

Prophecy99

iTrader: (1)

yeap.... burning oil is pretty normal on a vehicle older than 10 years... across any make/model, how much thats debatable but its always there

flames101sully

iTrader: (1)

eh, not really. Depends on the model... even a 12 year old Taurus I had didn't burn oil (but it started to rapidly lose it when two gaskets went bad at the same time)

rbaksi

iTrader: (3)

Here's what I did.

I got a $15 cheap catch can off of eBay. I disconnected the hose on the back of the intake manifold going to the PCV valve. I connected the catch can to the PCV valve, and let the other end of the catch can vent to atmosphere. I blocked off the intake manifold port to not create a vacuum leak.

This allows the PCV valve to vent gas/oil into the catch can, but it isn't actively being sucked out by the intake vacuum. The difference for me was dramatic, there is almost no oil in the catch can. When I had the catch can as a closed loop (PCV > Can > Intake), my oil burning was no different and the catch can would fill up very very quickly.

In addition, there is another way for crankcase pressure to get out - via the breather tube on the front valvecover that goes to the airbox

Now, the car definitely runs a bit smoother and the oil burning is a quart per 3-4K.

To see if the intake manifold is where your oil is going, open up the VIAS plate on the side of the manifold. If there's oil inside, its definitely the culprit.

SubwayVQ

I just gotta say, your car looks fantastic!

TSelanne

iTrader: (2)

From the master himself - Mr. Darren Surratt:
1- run closed stock pcv, with intake hose and pcv valve hooked up.
2- run open setup with front valve cover breather hose open (no hose going to intake pipe) and MAKE SURE drill out the pcv and run another open filter there. then cap off the intake manifold where pcv hose went.
3- run a closed system but with a catch can. If the PCV hoses go to catch can then back to the intake manifold its a CLOSED system which means you need a closed catch can. If you have a open catch can then your pcv system is open, so intake manifold needs to be capped off and intake pipe hose needs to be going to catch can instead of intake pipe.

His words regarding the pvc/crankcase:
"pcv valve pulls crankcase vapor when vacuum is high in the intake manifold (idle, low loads) the front hose going to intake pipe pulls crankcase vapor when there is not enough vac in the intake manifold to open pcv valve so it pull crankcase vapor (at high loads WOT)from the front valve cover hose."

rbaksi

iTrader: (3)

Thank you for sharing this, but one thing I don't understand - For scenario 2 why is it necessary to drill out the PCV? If there was any sufficient crankcase pressure would it not just be able to go through the breather hose or push the PCV open? Is crankcase vapor necessary to remove if there is no increased pressure inside?

rbaksi

iTrader: (3)

Thanks man!

TSelanne

iTrader: (2)

I think it's the first thing you said, that there's not enough pressure to open PVC. I'm not 100% sure though, I admit I don't fully understand.

Prophecy99

iTrader: (1)

thanks man , this helps !! so what was dramatic, once you figured out the new proper venting scheme w the Catch can installed? in other words u installed it closed loop and it filled up very very quickly, and then re did the venting config and it barely fills up?

Robert Baker

I'm not a total Car guru, but I do know enough that I felt compelled to say that The reason rings fail is a failure to properly break in the rings. 10 miles is all you have to seat in 80% of the rings. If you baby it or hard accel for too long you will have issues. Going to a race track is the proper way to break in the motor. If you think that going easy on the motor for the first xxx miles is the proper break-in procedure then you are the one who ruined the rings to begin with. After a fresh rebuild fire it up and look for leaks. Back that mother ****er down the driveway and full throttle it till redline, then without taking it out of gear decelerate back down to idle-ish. The idea behind this is to load the rings up and force the fresh hone/hash pattern to eat the rings and force a really solid mate. The only way to force the rings to eat the hone pattern is to increase the load on the rings. Carefull though because getting the rings too hot will result in the oil control rings becoming too hot thus buring the oil and glazing the cylinder walls.

kauaiwyatt

iTrader: (5)

There is enough pressure to open the PCV. I don't think you have to drill it out, bc I can hear it opening when I'm in high RPMs (kind of annoying whistling sound). I have both of my valve covers venting to the atmosphere, & it burns a lot less oil like you said. I might get this kit later: https://www.projectimport.com/store/...-breather-kit/