I've been noticing lately that a small oil leak I have had has seem to grown to where after I drive, I swear I lose at least 1/4 quart of oil on the ground, not counting what I lose while driving. And I cannot seem to find where it's coming from.

I noticed oil on the top of the engine towards the rear, down the driver side, all over the oilpan and front of transmission, on the starter, and electrical lines to the starter. Nothing on spark plugs or wires though. None at all on Passenger side though. So this really is weird. I'll get pictures up tomorrow as right now it's dark and rainy. I'm thinking the rear oil return line to the oil cooler, but I don't know. When the car is running, I see it dripping, but nothing leaking.

But, I think this might also be related to something else I have been worried over. Since I got this car, everytime I drive it, and check the oil, when I remove the Oil Dipstick or the Oil cap, a puff of air is blown out. And if I put the stick back in, a minute later I remove the stick and I feel the same puff. Now I realize that the crankcase is pressurized, but I have never heard a car do this before. But I think the issue is with my PCV. The top hose broke off. I'm assuming that is what opens the PCV valve so that the crankcase vapors can be pulled into the intake at WOT. What would be the issues with bypassing this valve?

 

if you don't have a strict visual check, run a catchcan.

 

Where is the PCV valve located? I wasn't aware that we had one... Pics help too.

 

PCV = Purge Control Valve. It's right next to the oil fill neck. It's a round saucer with vacuum hoses attached.

And I totally forgot my S4 had one. So I just went outside and swiped it from the other car. Fit perfectly. Now I just gotta find where my oil leak is. I'll post pics tomorrow. It's strange cuz everything on the bottom of the car is covered with oil. Starter, oil pan, tranny, all cables down there. I hope it's just a loose oil cooler fitting on side of engine. But idk. Other then the OMP+Injectors, is there anywhere else on top of the engine oil may come out of?

 

Ah-hah.

Sorry to get a bit off topic, but somehow mine has a vacuum leak in it so I took the top hose (the one going into the intake mani) plugged it + left it like that. I think my idle was fubar because of it. It was a long time ago so I can't remember exactly what was wrong.

What problems if any will happen because of this?

 

I don't know 100% how it works, but I know while idleing, the PCV is closed, leaving pressure in the crankcase. At WOT, the vacuum from the intake opens the valve, and allows excess pressure out back into the intake(I think.)

Don't quote me on this, This is just what I got from the FSM. So, I think you might need it. The idle problem with it though, might have been from it being blown? Allowing the vacuum to suck from it? I have no clue.

 

hmm ive been having leaks around the same areas, i think its coming from the oil pressure sensor and oil filter around the o rings. im also leaving a good amount of oil on the ground. do you have the check valve installed the right way? i just found out mine is missing. i dont know if that added air flowing in is enough to force oil out but its seems plausible!

 

See that little hole with oil coming out of it on the left? That's on the transmission.




These are how bad the oil leak is.

 

damn thats 100% worse than mine lol

 

I actually didn't know it was that bad. It wasn't like that last time I was under the car.

 

thats your rear main seal bud swap out the clutch while your in there

 

If it's leaking oil form the back of the engine - then it could be the oil filter, oil pedestal or a crack on the top of the rear iron - where the dowell pin goes through - there is a known fault with the older Series 4/5 cars that have a weaker rear iron that can go at this point - it only leaks when the engine runs, so you won't see oil there unless the engine's running.

Could also be from the rear oil line to the intercooler or from the oil pressure sensor mount.