oil in intercooler AAN

[Michael S2]

Looking for some pointers...
S6 aan
I've got lots of oil coming from the Michelin man hose. Lots as in there's always some left on the ground after parking overnight.

My first thought is turbo, but I have no smoke coming from exhaust. Car is not holding boost which I assume is the Michelin man hose leak.

Could it be the one way valve or pressure regulating valve?
Any help would be great.

[RichLV]

For turbo to leak oil, it doesn't have to smoke necessarily. My first turbo was leaking oil only on the intake side, through the big o-ring on the compressor backplate, so I almost always had oil in the intercooler pipes, but it did not reach the throttle body as the leak wasn't so bad. I did not experience any smoke.

Other thing is the crankcase vapors, oil from them likes to condensate on the walls of pipes it goes through. Catch can remedies this problem.

My 2c.

[merlin's S4]

It's very common to get oil collect in the bottom hose as this is the lowest point. The oil comes from the breather system being connected to the air intake. It will collect and get worse with age and will eventually rot out the ribbed intercooler hose. I would doubt that there's any real problem with the turbo unless there's tons of oil and smoke from the exhaust but the hole in the hose will cause a boost leak and a drop in performance.

Replace the hose (Samco do a silicone set for the AAN) and give the intake a good clean. You could also look at modifying the breather system with an oil separator and/or catch can to prevent the oil vapour being drawn through the intake.

[macspring]

If it 'oil' collecting on the Michelin man hose 'under' the alternator ?

It may be that the fluid is coming from the power steering pump. My pump's big 'cross head' screw is allowing fluid to be pushed out and 'flow' down the engine block and collect on the lowest parts in the engine bay. The Michelin man pipe and the exhaust pipe it as it is blown back under airflow.

Either way, two of my original pipes have blown due to rotting out with oil, regardless of it's source, so I would suggest you buy a new hose from say Rouse Motorsport, and also the more 'complicated' pipe leading from the turbo to go over the hard pipe across the underneath of the bottom of the car leading to the Michelin man pipe referred to above.

To be honest I bought the set of three pipes. The two mentioned above, and the one coming up out of the intercooler and into the throttle body. I fitted the first two pies, but not the "throttle body" pipe. This particular pipe doesn't seem to fail much compared to the other two. So it's on the shelf for the future.

My one from the turbo on the way to the intercooler, a couple of these originals have failed on me. They seem to lead a harder life that the throttle body.

HTH

Looking forward to see what the cause / cure is.

Best wishes.

[blackS2]

It's very common to get oil collect in the bottom hose as this is the lowest point. The oil comes from the breather system being connected to the air intake. It will collect and get worse with age and will eventually rot out the ribbed intercooler hose. I would doubt that there's any real problem with the turbo unless there's tons of oil and smoke from the exhaust but the hole in the hose will cause a boost leak and a drop in performance.

Replace the hose (Samco do a silicone set for the AAN) and give the intake a good clean. You could also look at modifying the breather system with an oil separator and/or catch can to prevent the oil vapour being drawn through the intake.

This is the correct solution. I did this on my former S4 AAN and on my S6 AAN. The Michelin Hose is rubbing on the (dont know the english word for the plastic under the engine room) and gets leaky. Also the lower T-Hose was leaky. The oil is from breather. Exchange to Samco - issue gone!

Here a few pictures -->

http://www.s2forum.com/forum/album.php?albumid=438

[andy10v]

Looking for some pointers...
S6 aan
I've got lots of oil coming from the Michelin man hose. Lots as in there's always some left on the ground after parking overnight.

My first thought is turbo, but I have no smoke coming from exhaust. Car is not holding boost which I assume is the Michelin man hose leak.

Could it be the one way valve or pressure regulating valve?
Any help would be great.

Sounds like a couple of issues.

I would inspect the breather system, clean, repair and replace as required.

I would boost leak test the car and resolve any leaks.

I would clean the hoses and monitor.

Some oil passing through the breather is normal, excessive is an issue. The turbo seal can also leak oil into the intake

Is the oil leaking out of a split in the hose? Could also be another leak dripping down as mentioned above.

As it is an old used car, the chances are the breather system is gummed up and half rotten, the intake hoses if original will likely be due replacement.

If you have the cash I would just replace all the boost hoses, all the small bore vacuum hoses, all the perishable breather parts. Doing it in dribs and drabs over the years is just a PITA, and lets you down each time something fails.

[Michael S2]

Thanks everyone some great advice as always. More investigating to be done.

Hopefully get a better look for the source tomorrow. Now you mention it macspring, I did top the power steering fluid up about 10 days ago and i'd say the puddles of oil are larger since thinking back.

It does look like the leak is coming from the Michelin man hose hence why my instinct was engine oil. First check tomorrow will be the fluid levels. Then clean everything up in the surrounding area.

Now know what people mean when they say a boost leak feels like you're about to get thrown through the windscreen...makes overtaking interesting

24 hours worth of oil below

[UrS4boy]

That might be engine oil but with that much it seems more likely to be PS pump fluid.

[macspring]

If you have the cash I would just replace all the boost hoses, all the small bore vacuum hoses, all the perishable breather parts. Doing it in dribs and drabs over the years is just a PITA, and lets you down each time something fails.

Good sound solid advice - ( BTDT ) as is the rest of the post.

What needs to be established first off is it oil or ps fluid. And secondly is it coming from a split in the Michelin man hose or draining down around the hose from above.

Being able to get under the car and clean it down and then check on it after a few days sounds like it might be a plan.

I was just thinking while reading these posts where people are having problems with their S cars, especially where the cause is not obvious, it is a right pain for the 'victim', as I've also experienced in the past myself, it's easy to reply and look to help when your own car is running sweet. Hope I haven't put the hex on myself / car with that musing.

Anyway best wishes with this problem, with the help of the forum you will get through this one and any others that surface. This one while annoying, is certainly not the worst.

[blackS2]

additional info...

PS fluid is green if you put a tissue on it (if fluid is not to old) - but I think you will see green trails on tissue

on AAN often the upper cross head screw O-ring tends to leak - I had to replace it on my S4 AAN

on AAN my smaler oil pressure sensor (the one with only one cable) was leaking straight trough the 6,3mm electric connector.

[macspring]

additional info...

PS fluid is green if you put a tissue on it (if fluid is not to old) - but I think you will see green trails on tissue

on AAN often the upper cross head screw O-ring tends to leak - I had to replace it on my S4 AAN

on AAN my smaler oil pressure sensor (the one with only one cable) was leaking straight trough the 6,3mm electric connector.

Good information

Like the tissue idea. Even though it is obvious I didn't think of it.

BTDT big time with mine. There was a small gouge in the 'o' ring seal causing my "power steering pump nut weep" leak.

No problems with my sensor today. :roll eyes:

[macspring]

Michael, did you get to the bottom of this issue ?

How many miles are on the engine ? Sorry as this may have been mentioned on here already.

Thanks.

[Michael S2]

Thanks again for the repsonses I'm faily sure it's leaking from the X plug on the power steering pump. Got a new plug and seal, but removing the old one

Tried a few makeshift ways, but i'm worried about exerting too much force and rounding it. The grooves are not as deep and seem a tiny bit wider than on the new plug so getting something to fit without slipping is proving difficult. Hope to get a better look this weekend.

Low miles engine 154k compared to my S2

[Michael S2]

Once i get this sorted i'll be removing the michelin man hose for closer inspection. Contacted Roose in preperation of replacing, but they said they don't make a boost hose kit for the C4 S6. I was sure i seen someone on the forum replace these with a kit from Roose

[RichLV]

Ebay has plenty.

http://www.ebay.com/sch/i.html?_from...e+hose&_sop=15

I have a red hose set from China. All good. I'm on stock boost though.