Help, Pressure in the PCV system causing oil leaks and Gunk in the PCV system.

[Flotronux]

When I Bought my A4 I had a lot of oil loss and was having to add oil often. I then realized It was being forced into the turbo and intake system by a faulty pcv and valve cover vent tube. So i replaced the Vent tube that runs from the valve cover to the turbo and I installed a ecs tuning catch can instead of a pcv. then I drained and cleaned all the oil out of the intercooler tubes which was atleast a quart of oil. Then everything was running great and I really liked the catch can. No more oil loss either everything running like it should. In the summer i was having to empty the catch can once a week which was ok but winter was causing me to have to empty the catch can every 2-3 days and It was annoying so I bought a NEW Pcv valve and installed it.
Well by my first oil change since the NEw Pcv vlave i realized I was losing oil again and this time it's being forced out of places like the oil filler cap, the oil filter housing and once again the PCV vent tube into the turbo inlet, It even crushed my oil filter cartridge It sucked it in so tight that i had to cut it off the oil filter housing center section. So I definitely have pressure building up inside the motor forcing oil out where ever it can go.
Not only that but all over in the PCV system There is a Creamy gunk lining everything. The gunk is not in the oil pan that i can tell or in the head as you can see from the pictures just in the PCV system. Also this time the oil being forced into the turbo inlet form the valve cover vent tube is the creamy color thicker oil.
What do you guys think is wrong here? I'm assuming the New Pcv valve I bought must be bad? But would that cause all the Gunk as well? what's forming all the Gunk I've never seen that before in this motor till between the last oil change and this one. other wise the pcv tubes have always been dry or have your normal brownish oil in it never this banana cream pie stuff! The original problem i had with the oil loss when i bought the car, the oil that was being forced into the turbo inlet it was normal brown oil, like i said this time it's the gunk oil.
I also ended up having to replace the oil level sensor in the oil pan it went bad at the same time all of this other stuff is happening. Thanks for any help!

[Endmass]

That funk's normal on cars that never get up to temp to burn off water vapor in the crankcase.


Do you drive few miles? Never run the car hard? Does it get upto operating temp ever?


Is the tstat good?

[Der Konig]

I have this too and I do run the car hard and drive 45 miles to work and back everyday. I have a feeling it may have some correlation with our climate up here, condensation build up could be more of an issue here maybe. Baffles me too but doesn't seem to be hurting anything, but I have a catch can and that thing catches ALOT of water/oil soupy mix.

[1killera4]

Thats water in your oil...what does your coolant look like?

[Flotronux]

Hey thanks guys the comments already made have connected some dots for me. one thing I didn't mention is that the motor lately has been running more on the cold side and the coolant system isn't operating quite right. I have a misfire every time i start the car in cylinder #4 and I'm not only losing coolant and having to add it but i can smell it and see that it's burning out of the exhaust. So I'm suspecting a cracked head or a head gasket going bad on me ( i hope the blocks don't crack on these motors). I assume the coolant is fouling out my #4 spark plug every time I start the car. So that makes sense now that the gunk is probably forming because the engine temp is not stable it's either on the cold side or normal...never over heats though. I don't see any coolant in my oil when I drain it and I don't see any oil in my coolant as far as I can tell.
So that solves the gunk problem but any idea's for the excessive positive pressure in the PCV/ Oil system? I don't think the head/head gasket is so bad that it would be putting pressure in the PCV/ oil system, and the high pressures in the PCV/ oil system didn't start happening until I removed the catch can and put the NEW PCV on. It looks like the PCV is working because I see gunk before and after the PCV valve but that's not to say it isn't working 100% normal.
Is the PCV valve and valve cover vent tube the only things that can cause high positive pressures in the PCV/ oil system? Or Maybe I am getting cylinder compression in the oil system due to a bad head gasket but it would be so weird that it just started happening at the same time I removed the catch can and put the PCV back on. And the head gasket or cracked cylinder head must not be horribly bad considering after it starts and smooths out from misfiring, which is usually 10-20 seconds it runs normal with no issues beside coolant loss and I have no oil in my coolant or coolant in my oil, unless the amount of coolant in my oil is a small amount that i can't see much and most might be getting burned off during combustion. By the way i've been fighting this misfire in cylinder #4 for a long long time way before the abnormal positive pressures started happening, but maybe the cracked cylinder head or gasket are just getting worse on me lately? at first a long time ago i never thought to suspect a head gasket or cylinder head for the misfire issue I was always chasing carbon build up BUT after i noticed the pattern of always #4 misfiring and now the coolant burning out the exhaust I realize my misfire has got to be due to the cylinder head being cracked or a head gasket going bad. #4 spark plug always looks crappy and chalky compared to the rest of the plugs.
Again thanks for any more insight to my problem!

[Theiceman]

dude you do see coolant in the oil , what do you think that milky stuff is . Normally its due to condensation but you have a serious intermix issue. forget your pCV issue and fix the elephant in the room , sounds like you have a bad head or head gasket. If you get coolant in the oil this bad it will toast your bearings fast.

[1killera4]

dude you do see coolant in the oil , what do you think that milky stuff is . Normally its due to condensation but you have a serious intermix issue. forget your pCV issue and fix the elephant in the room , sounds like you have a bad head or head gasket. If you get coolant in the oil this bad it will toast your bearings fast.

May not be an elephant in the room but there sure is an echo.

[Flotronux]

How come I don't see milky oil in the oil pan or in the upper part of the head then? I posted a picture on the head with the valve cover off, looks pretty normal. UNLESS its just a small amount of coolant in the oil? I realize any amount isn't good.

But i am in the process of removing the head and i'll have it checked for cracks and if there's no cracks i'll just replace the head gasket.

And my biggest issue is the excessive positive pressure in the oil/ PCV. Or are you saying the pressures are coming from the cylinder compression finding its way out of the cylinder? I did a compression test and all four cylinders are at 170 psi. And like i said the positive pressures just started happening the last two months so it's either something other than the head gasket/ cracked head causing that issue or the head gasket is just getting worse lately?

Also just recently the oil level sensor went bad and i had to replace it, could small amounts of coolant in the oil have caused that to happen as well?

[Older_not_Wiser]

And my biggest issue is the excessive positive pressure in the oil/ PCV. Or are you saying the pressures are coming from the cylinder compression finding its way out of the cylinder? I did a compression test and all four cylinders are at 170 psi. And like i said the positive pressures just started happening the last two months so it's either something other than the head gasket/ cracked head causing that issue or the head gasket is just getting worse lately?

I had issues with my PCV pressurizing my crankcase under boost. I stuck an analog vacuum/pressure gauge into the dipstick tube and could watch the crankcase pressure rise with boost and get up to 4-6 psi. Would not do it every time. My theory was when you roll onto boost slowly, the gunked up PCV would not close the valve/flap and pressurize the crankcase => oil leaks. When you stomped on it a bit, the rapid change from vacuum in the intake manifold to boost in the manifold allowed the PCV valve/flap to close thereby not letting the boost into the crankcase. I bought a brand new PCV and it did the same thing.......couldn't believe it so I bought a second new PCV and that one functions normally. Have since changed to VTA catch can set up and only use the PCV when I have to get smogged.

[nizmosx]

Would a bad or cracked oil filter housing cause this? if i recall coolant runs through the oil filter housing. im new to the 2.0t motor but its just a thought.

How many miles on your car? i hear those housings usually go bad around 100-110k miles.

[mtroxel]

I would not assume that a head gasket problem is not related to the pressure in the crankcase. If there is a crack in the head, or a leaky intake valve, you could have combustion gasses/pressure going back into your intake> PCV.

But i am in the process of removing the head and i'll have it checked for cracks and if there's no cracks i'll just replace the head gasket.

I've done just enough heads to know you can't always find cracks yourself. Take it to a shop. No point in just doing a head gasket and being right back where you are.

[Flotronux]

I would not assume that a head gasket problem is not related to the pressure in the crankcase. If there is a crack in the head, or a leaky intake valve, you could have combustion gasses/pressure going back into your intake> PCV.



I've done just enough heads to know you can't always find cracks yourself. Take it to a shop. No point in just doing a head gasket and being right back where you are.

Thanks and Yes, i know exactly what you mean, I pretty much figured I would not be able to see and cracks because the car mostly runs fine so if there is a crack in the head it's probably hairline tiny so i planned on sending it out to get tested. The last thing I want to do is be back to square one.

Hey and much like your self i owned a late 90's a4 with the 2.8 and it went 225,000 before i traded it in. ROCK SOLID motor never had to work on it. Too bad the turbo motors seem to be problem after problem. I even have had two a6's one with the 2.7 turbo and one with the 4.2...again the turbo motor needed work and maintenance often but the 4.2 is rock solid. I still have the 4.2 a6 and love it. I'll stay away from audis turbo engines from now on.

[Theiceman]

yeah I think the biggest red flag is smelling the coolant and your coolant going down , I think you are burning it. Did you actually take your pan off and pour out the oil in it ? if its intermix the milky stuff will be in the pan at the very botton under the oil. its usually a thim film you see as you pour off the oil.

As mentioned if you have a cracked head or head gasket all bets are off , you can be pressurizing all sorts of places depending on where it is .. . it is certainly conceivable that a cracked head would allow combustion pressure into the crankcase that would overwhelm the PCV and pressure the crankcase .
I think further diagnosin is required . if we look at the facts you have presented.

1. Overly high crankcase pressure
2. White Milky substance
3. Sweet Smell
4. Coolant going down .

It doesn't loo too promising. usually if you pull the plugs and find one that is unusually clean , it is because it is being steam cleaned by the coolant that is getting in and burning.

[Flotronux]

yeah I think the biggest red flag is smelling the coolant and your coolant going down , I think you are burning it. Did you actually take your pan off and pour out the oil in it ? if its intermix the milky stuff will be in the pan at the very botton under the oil. its usually a thim film you see as you pour off the oil.

As mentioned if you have a cracked head or head gasket all bets are off , you can be pressurizing all sorts of places depending on where it is .. . it is certainly conceivable that a cracked head would allow combustion pressure into the crankcase that would overwhelm the PCV and pressure the crankcase .
I think further diagnosin is required . if we look at the facts you have presented.

1. Overly high crankcase pressure
2. White Milky substance
3. Sweet Smell
4. Coolant going down .

It doesn't loo too promising. usually if you pull the plugs and find one that is unusually clean , it is because it is being steam cleaned by the coolant that is getting in and burning.

Thanks iceman, I'm currently going to send the head out for checking for cracks, replacing most the PCV tubes and valves and obviously will be replacing the head gasket and valve seals. So hopefully hitting all that takes care of my issues. I'm definitely burning coolant so it's either a gasket or cracked head for sure. I just didn't know if the high crankcase pressure was related to something else but it could be the gasket, head or PCV. so i'll just do it all to eliminate all possibilities.

[Theiceman]

Thanks iceman, I'm currently going to send the head out for checking for cracks, replacing most the PCV tubes and valves and obviously will be replacing the head gasket and valve seals. So hopefully hitting all that takes care of my issues. I'm definitely burning coolant so it's either a gasket or cracked head for sure. I just didn't know if the high crankcase pressure was related to something else but it could be the gasket, head or PCV. so i'll just do it all to eliminate all possibilities.

I have been teaching trouble shooting for over 20 years and there is one thing I teach all my students when hit with an unusual problem they cant figure out.

" fix what you see before you fix what you cant see"

I think your approach is a good one.