Oil leak driving me crazy! please help

B6/7 S4/RS4
#1

My 2004 S4 has had an oil leak in the front of the engine for awhile now but has recently gotten worse. I can’t see exactly where it’s coming from but I’ve already replaced the front crank seal and valve cover gaskets. I can see it dripping down onto the coolant crossover pipe and more towards the right side (passenger side) of the engine. My only two guesses are either the oil cooler or where the upper oil pan bolts to the block. But I haven’t found any of those being common leak points on any forum. I have access to a lift and tools but the car is my daily driver. Any tips or links to other posts would be greatly appreciated. Thanks!

Frank

#2

Welcome Frank you’ve come to the right place there’s tons of incredibly well traveled members here that can help you. I’d say first off do you have any pictures of the oil leak? When you did your valve cover gaskets did you clean the front of the motor? I’ve noticed on my car even though I replaced my valve cover gaskets when my crank case ventilation system was clogged I’d leak out little streams of oil. This might be the issue in your case. Are you certain it’s not coming down from higher up?

#3

I changed my front crank seal about 5k miles ago and cleaned everything really well. It’s a pretty bad leak now and seems to be worse when hot. And it’s also sporadic. Sometimes not a drop and other times I’ll have a quite a bit on the ground after only being parked for a couple hours. I’m fairly certain it’s coming from a point below the valve cover because I can see in there with a mirror and it looks dry. I don’t have any pictures. I’ve narrowed it down to the front, right corner of the engine in the area of the oil cooler. But I can’t see anything without removing parts. Where exactly was yours leaking from? I haven’t checked my crankcase vent system nor am I exactly sure how. :-\

#4

The pcv might be something to look at if it’s keeping too much pressure in the crankcase that can push oil out of areas it wouldn’t normally come from.

The oil leak would have to be either the crank seal failing and the oil is getting kicked over to the side or it could be from the oil cooler but the oil cooler wouldn’t be a sometimes kinda thing from what I’ve seen. It’s rare that they leak but it’s bad when they do. If you don’t see any oil coming from the valve covers those would be the usual suspects. How much oil are you loosing

#5

I’m not sure on an exact amount but it’s getting pretty bad. To the point where when I just stop for gas I’ll take a peak and see drops dripping down. I came home today and parked in my driveway for only about an hour and came out to a fresh spot about the size of a dinner plate. I don’t think it’s the crank seal because the oil doesn’t seem to be evenly spread, only seems to be on the right side mainly. Plus I can’t imagine a crank seal leaking that bad. But I could definitely be wrong. I had it on the lift a few days ago and around the crank pulley seems fairly dry. The bolt that goes straight up holding the upper oil pan to the block is where I can see fresh oil dripping from down onto the coolant pipe but I can’t see anything above that without removing parts. My only thoughts were the sealant between the “girdle” and block is gone or the oil cooler.

#6

Sounds like something not normal so I can see how this would be frustrating. It’s a hard spot to see in and there isn’t much you can do unless you start moving stuff away.

#7

Have you had a chance to remove the splash guard under tray and look from the bottom? Is it possible one of the oil lines or oil line connections in or around the oil cooler is failing? Intermittent dripping is strange and hard to pin point.

The PVC like others have said is a good item to check. Like Justin mentioned, if it’s clogged or faulty it can build up the cc pressure and start forcing oil out of spots it wouldn’t normally come from. Forcing a seal to move a bit or expand etc temporarily, which might explain the intermittent drips.

Keep us posted.

#8

Yes I removed the plastic splash gaurd and had it on the lift a few days ago. Definitely coming from the area of the oil cooler but that’s as far as I can see. It’s not really intermittent anymore. Leaking pretty heavy now which I would think would make it easier to find. I was really hoping someone on here would have had a similar issue and could give me a golden nugget of info. I hate oil leaks. I think I’m gonna be forced to start removing parts and see what I find. And how exactly do I check the pcv system? Do I just pull the lines off and/or the valve and see if it’s plugged? This car runs great and I hate for it to be ruined by this issue. Thanks for the help so far guys.

#9

When i bought my car i had an O ring in the oil cooler that according to Audi wasnt OEM. It was leaking pretty good. The conclusion was the dealer where i bought my car did something maintenance wise and put in the wrong O ring. You could try that out.

Also i know it may seem far fetched but what about the oil pan leaking? When i recieved my new engine, Audi missed a 1/4 of it with the sealant. It didnt leak until the engine was on and when it did, it was significant.

#10

Thanks. The leak is coming from above the oil pan. But I know these engines have the small black lower pan and the larger aluminum upper pan. Sometimes called a girdle. I wouldn’t be surprised if that upper pan is leaking. In that case it would require extensive labor and engine removal to reseal it. Maybe I’ll start with the oil cooler and while I have it off and apart I can take a look around. In reality there’s really not much else there to leak. Unless the block is cracked and I find that hard to believe.

#11

This really isn’t falling under the usual suspects. I would put someone in the car and raise it up on the lift. Have them start the car and look for the leak. Snap a few pics if your not sure. I can’t see how you would have a crack in the block and not know it. So I would think it’s got to be coming from the oil cooler.

#12

Imho I wouldn’t imagine your upper oil pan is not leaking because you said it leaks while sitting after the car is off. Almost all of the oil that is in the upper oil pan drains down into the lower oil pan moments after the engine is shut down. Especially the oil that would be present where the oil pan meets the block. However your oil cooler would be holding residual oil from when the car was running. There are one way valves to prevent the oil from draining back into the pan. Otherwise the oil pump would loose it’s prime. So the oil cooler always has oil in it. I’d start there.

#13

I meant I wouldn’t imagine your upper oil pan IS leaking. I do believe it is not leaking.

#14

Just wanted to try bumping the thread to see what the leak was

#15

Sorry for the long delay. I unfortunately have not taken it apart or have any updates because I’ve been so busy with work/school/holidays/vacations, etc. I do have new oil cooler o-rings, just need to find the time. Probably within the next couple of weeks. Also, I just posted a new thread but probably should’ve asked here first, do any of you have a link to removing the front bumper/carrier? I had a link to another forum with it but that link no longer works. I need to remove the alternator to get to the oil cooler. Thanks again for the help.

#16

Frank85

Here is a link for putting the bummer into service position.
http://audirevolution.net/forum/index.php?topic=3725.0

If you want to take it all the way off you will have to disconnect the AC lines, coolant lines, and PS lines. When removing the headlight washer line from the pump be careful with it, it is pretty fragile and easy to break. I don’t think they are Italian though. Also, there will be a couple of electrical connections that will need to be un-clipped. There are two in the bumper when you pull that part off. To remove the carriage there are also a couple connectors that need to be undone. There are two that are about the drivers headlight. In the link you can see them next the PS reservoir at step 6. You will also have to remove the accelerometers for the airbags. I would recommend leaving them plugged in an just unbolting them. There are yellow sensors on either side of the radiator. You can see the airbag sensor resting on the PS reservoir in step 7 of Bone’s post. Just make sure to use some loctite when putting them back on. Vibration like to make bolts come lose and those are some you don’t want coming out. Also make note of there direction the have an arrow that should be pointing forward. Aside from all that you will be more than fine following JimmyBone’s guide. I might be missing a couple steps since this is all from memory, but I’m sure someone will chime in, if I have.

Regards

#17

Good follow up motoman

Just to kinda make a few points clear that might not be 100% understood.

You dont actually have to remove the AC stuff your just going to have to swing the condencer unit on the front of the motor out of the way. And your not actually taking off the PS lines your just taking off the lines to the PS cooler. Taking off the air bag sensors is a good idea but you dont need to put on loctite when you put them back in. The sensors are light and there isnt any load or moving parts associated with them obviously you can put loctite on if you want but I have never seen any issues reinstalling them without it.

#18

Update: in the end it was the block leaking between the midplate and lower case. Due to the mileage and cost of repair I sold the car and bought something newer. Thanks for the help and updates. I hope to own another Audi in the future. Until then I’ll enjoy my leak free Mercedes ;D

#19

Whoops, I didn’t see how old this tread was. Sorry for bringing it back. Hope you enjoy the new car Frank85!

#20

Its still cool to pop in old threads to help layout good information for people that find the threads in a search