heel2toe

iTrader: (41)

UPDATE See post #39 https://www.evolutionm.net/forums/10800891-post39.html

For the past ~8 months i've been trying to diagnose a mysterious oil leak. During a normal OCI (~3000 miles) I need to add ~.5 quart of oil, maybe a little more.

The leak is slow enough that it will never leave a puddle under the car however it is making a greasy mess on the back of the block and and around the oil pan. I cannot seem to track down where the oil is coming from.

Tonight I was pulling my intake manifold to swap in a ported one and after pulling off the stock one I found oil in the runners of the IM. What could be causing this? My compression is the following: 1-190 2-182 3-186 4-190 which seems to be great.

After researching online I see people talking about a faulty PCV. Could this be the culprit? Im skeptical because I have my PCV running into a catch can and the nipple on the IM capped off. what else could it be?

Im hoping its something stupid and a quick and easy fix, obviously so hopefully someone can chime in so I can get this taken care of. thanks for your help!

sobo

iTrader: (15)

In my experience, you basically will always find some sort of oil in the intake. PCV is designed to put that positive crank case pressure directly into the intake system, and sometimes oil comes with it. People build and sell catch cans for exactly this reason. How long have you had the catch can on? This could be oil from a while ago.

Additionally, if you have a bad seal on your turbo it could also be causing oil build up in the intake. Take off one of your intercooler pipes and inspect for oil if you'd like to check. That's going to be your only other source of oil that could enter the intake manifold like that.

Greasy mess in your engine bay? I'm not sure how many miles your car has on it but this is basically something common with cars that have been driven.

Czarcasm

iTrader: (18)

If the pcv is not hooked up to the IM, only thing I could think of is oil being sent into the intake thru the hose thats hooked up to the valve cover. You see any oil in the charge pipe?

heel2toe

iTrader: (41)

Ive been running the catch can for over a year now. Its a vented setup and both valve cover breathers run into it. As for the oily mess, the IM runners had oil in them ad well as the ports on the head where it connects. The oil is then seeping down onto the back of the block.

Could this have anything to do with valve seals? The car doesnt smoke or anything. Where else could the oil be coming from that would end up in the IM and then leak out onto the back of the block?

heel2toe

iTrader: (41)

What hose are you referring to?

Czarcasm

iTrader: (18)

The one thats next to the front cam sensor or did you route it into the catch can also?

If the valve seals were bad I would think you would get blowthrough at the dipstick at high psi, as if the rings were bad, would also fill up the catch can rather quickly. Are the charge pipes clean or is there oil in em?

heel2toe

iTrader: (41)

Thanks so much for your help!

The line on the valve cover near the cam angle sensor that usually runs into the intake pipe is routed to the catch can.

I pulled off my UICP when removing the IM so I can check to see if there is oil in there? Maybe I am better off looking at my LICP though since its right after the turbo?

Im nervous that its something like valve seals though bc I dont know where else this oil could be escaping from.

The catch can does fill up about every other oil change although I typically empty it every oil change. Its mostly some liquid substance which I suspect is gas as well as water vapor. Then there is some milky like oil substance so its not like pure oil is going into the catch can like the oil that I found in the IM.

My compression was good and there is not any significant blowby that I know of. The dipstick has never popped out and I dont hold it down with a spring or anything like that.

I have a couple of spare PCV's from some cracked valve covers that I have (thanks evom scammer!). How do you test that my PCV has gone bad and even it if was bad how could that lead to oil in my IM and seeping down the block?

Do you have any other ideas?

meckert

iTrader: (11)

One piece you didnt touch on is the oil sending unit---they leak all the time, its in your picture under the intake and can leak as discribed ( down the back of the engine) However, wouldnt address the intake issue with oil in it-- two different things-- since you have the intake off, spend a few dollars and replace the oil sender.

heel2toe

iTrader: (41)

I appreciate you mentioning that. Im not familiar with that part. Can you point out where it is as well as link me to a replacement one? Since my car is down and apart I would like to address as much as I can. Once I see what you are talking about I will inspect it to see if that could be the cause of a lot of my oil.

Maybe that is leaking but I also have a little oil in my IM. I just assumed that since I found some oil in my IM that is where my leak is stemming from. I think you may be onto something though because even if my IM had some oil in in, how would the oil be escaping and running down the back of my block?

I think what you just brought up may be my actual problem I hope that part isnt too much! Thanks so much for mentioning that. Once you provide me with additional info I can investigate it myself.

joseph143

iTrader: (8)

Sending units tend to be cheap... My maximas was 7 bucks... However they get full pump pressure so they usually leave a huge mess... Personally you compression number look off the charts high for what i assume is a stock block.

I personally noticed i had more blow by at my turbo and more oil in my catch can when i didnt use my pcv system... Running the setup vta allows pressure to build in the crank case due to restriction in the vent and that backs up the turbo drain along with pushing bits of oil thru all the seals... Same thing happens to under vented high boost cars like mine was... Anyway hook up you pcv to the intake or preturbo so that crank case can depressurize and you should be fine. If not then get the stm balance shaft breather fitting and upgrade your lines to -6an and you will definitely be good...

heel2toe

iTrader: (41)

Is this the part you are referring to?



http://streettunedmotorsports.com/pa...ure_switch.htm

heel2toe

iTrader: (41)

I wonder if my oil sending unit is causing the oil leak, and my catch can is the cause of oil in the IM. Now I am starting to think I have two separate issues.

As for my catch can setup I made it myself although its very similar to STM's design. A couple notes about it. I have my PCV still connected to my IM and that line that normally runs from the PVC on the valve cover to the IM now goes into the catch can. The nipple on the IM is capped off. The other line that normally runs from the valve cover into the intake pipe also runs into the catch can. The can has a breather on on and there are no external check valves or anything like that. IIRC the lines are -8an however they are reduced down to fit both the PCV and valve cover.

What you are saying is that I have no vacuum to help relieve the crankcase pressure, correct?

heel2toe

iTrader: (41)

I need to get my car back together ASAP so any input that you guys have would be more than appreciated. It sounds like the culprit of the oil leak could definitely be from the oil sending unit. Since its so cheap and the fact that I have easy access to it right now I think it makes sense for me to order one and swap it out just for good measure.

Can anyone give me more info on this part as well as what I can do to confirm that its faulty? It looks like oil is indeed around it but oil is everywhere on the back of my block right now so its hard to tell the source.

Also is there a special tool that I need to remove and install the new unit? Thanks so much for all of your help! I am looking to order this part as soon as possible so prompt responses are much appreciated.

heel2toe

iTrader: (41)

So I just stopped at the dealership and picked up a new oil sending unit. I see that it can be installed with a normal socket. Does anyone know what the tq spec is and are you guys using some sort of sealant or threadlocker to keep it from leaking?

Other than seeing the obvious oil around it, how does one diagnose a faulty oil sending unit? Thanks for the assistance!

joseph143

iTrader: (8)

Like i said they normally are heavy leaks.

Cant speak on torque spec tonight.

Future reference i crank my cArs til the srs light goes out while doing a compression test.

And yes you need to get some sort of vacuum into the case. Race setups is okay to puke into a tank, they also use some extreme vent setups and yours sound very minimal. I am following the advice of a good friend and top fuel engine builder and just installed an "evac's" kit to help curb the issues caused by stroker pistons. It would be overkill for you but anyway. The intake mani line and preturbo line are there to vacuum out the pressures of the crank case. If they arent used then serious measures need to be taken in there place. Ie evacs,vacuum pump, or dry sump kits...

Or you burn oil, reduce octane levels, build a carbon layer inside the head that creats hotspots... All of which lead to detonation... Trust me here... Anyway its late, i cant sleep, not sure this made a lick of sense because im on my phone. Best of luck. Fix your pvc system. "Positive cranckcase ventilation" incase you were wondering