![]() |
Oil Leak / PCV Puzzle
hello, I'll try and keep this succinct. looking for help on tracking down an issue or two. trying to figure out where the oil is coming from, because its all over, and i can't make sense of what the source issue is. ill get it eventually but i would love some input from (hopefully) more experienced folks.
full album: https://imgur.com/a/nMjv6vW
oil was found: all around the PCV valve area. wettest just below the PCV valve in areas circled (not sure what to call it exactly) oil residue also in areas above PCV where it would not flow "uphill". if its vapor laden blowby gasses escaping from the PCV tubing, perhaps thats explaining the spread? https://i.imgur.com/3C2lsGI.png oil residue also found around the breather hose on the top of the intake manifold. i had wiped most of it off here already. it was fairly damp. https://i.imgur.com/AP7s7Z4.png oil residue also found on back of intake manifold, and on intake manifold underside as well (not a whole lot here, but noticeable) https://i.imgur.com/PNvfXnD.png lots of oil residue inside intake manifold. each port pretty much looked like this. the inner walls are not 'wet' despite looking like droplets but can be wiped off with a rag. the gasket area is definitely wet. how normal is this? certainly does not look ideal - but this is my first time pulling an intake manifold https://i.imgur.com/fH12D9F.png POV from throttle body looking inside intake manifold, you can see what appears to be oil splatter pattern as if oil was flowing into manifold from air intake. or maybe coming in from pcv hose and just making an instant U turn to hit the back wall? https://i.imgur.com/140EZhj.png breather hose port in the air intake tube from driver front PCV(CCV?) system, showing oil leaking into it, and patterns of it being drawn in https://i.imgur.com/OUPYYud.png pics of catch can that was on the car when i bought it (bought the car last year) hose to manifold was slightly kinked but not shut as far as i know. the hose going to PCV valve did not seem like the best connection (hose was cut crooked) never more than a tablespoon of oil in the catch can after several track days and hundreds of miles. https://i.imgur.com/Fcue5tO.png all intake ports looked like this pretty much https://i.imgur.com/1TWZ88T.png also one direct injector tip was oily what does it all mean? thanks for any input. i have not done any compression or leakdown tests. until now no reason to even consider one I'm thinking my crankcase pressures, meaning vacuums, are wonky. I am not sure why there would be oil leaking into the air intake like that unless for some reason that is pulling a strong vacuum, which as far as i know isn't supposed to happen maybe accusump is causing overfilling and resulting in a lot of extra blow by? could it be possible that oem pcv valve has failed? |
Get a better catch can setup for sure. You've got lots of blow by for some reason. Leak-down seems prudent
Sent from my ONEPLUS A5010 using Tapatalk |
Quote:
|
Get a leak down test before investing another penny.
|
Quote:
|
bump if anybody else has input
|
Two of the most common oil leaks (which I recently have now) is the Cam plate and Timing Chain cover.
|
Quote:
right now my money is on the PCV connection. hopefully this has been caused by weird crankcase pressures, hypothetically due to the mishimoto catch can. if that isnt it, i then most likely have a really bad blowby problem, and im also looking at doing a leakdown test to try and rule that out. |
Quote:
I have the same oil catch can. Finally emptied it after 2 years and it was 1/3 full. I'm boosted and haven't seen oil around that area on mine. Try to do a vacuum test (using a smoke/fog machine). When going boosted, you want to replace that PCV valve with an STI one since stock can't handle it. Mine wasn't seated correctly (by me) because it's a tight area and I couldn't get to it. Took it to a shop and they smoke test it to find it, they had a hard time tightening it as well but got it done. |
update, pulled the plugs, and took some pics of the piston heads. 3/4 of the plugs had an oily base, tips look fine as far as i know. all piston heads had this same damp-ish appearance. hoping to hear back from the injector servicer that they were leaking and thus explaining damp piston tops. still haven't done the leakdown yet
https://i.imgur.com/frcMUgH.jpg https://i.imgur.com/kOFd9p2.jpg https://i.imgur.com/j1cytaU.jpg |
Quote:
PCV valve is getting replaced but just oem. the jackson racing kit has an in-line check valve to handle the extra pressures included. so the plan is to just install as they intended. at tuners recommendation |
update: replaced the PCV valve, and the brand new valve had a much more freely moving valve inside than the existing one. the new one will move around when simply turning it upside down, the old one has to be forcibly shaken to get movement. i'm not sure if that is significant or not. by comparison, it felt like the old one was gunked up or something. i can't say if it was 'out of spec', but it would surely be more difficult for a pressure difference to actuate it, especially through a catch can. maybe that helps point toward a faulty PCV being my issue. Either way it was interesting to see the difference between mine and a brand new one. figured i'd share that.
for now i'm deleting the catch can and using a new PCV to see how things go. no leakdown or compression yet. |
How is it holding up now? And have you installed the SC?
Sent from my SM-G781B using Tapatalk |
Quote:
Any updates ? |
| All times are GMT -4. The time now is 01:25 PM. |
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2026, vBulletin Solutions Inc.
User Alert System provided by
Advanced User Tagging v3.3.0 (Lite) -
vBulletin Mods & Addons Copyright © 2026 DragonByte Technologies Ltd.