Turbos - oh dear, the saga continues

[Jim Haseltine]

There will always be a little bit of oil in intercooler pipes - but anything more than a couple of teaspoonfuls (so say 10mL) building up in there over a year would be something of a concern.
However, I think with the RS6 it's dependent on oil level and the condition of the breather & lubrication system - if the oil level is too high and/or the system isn't oil tight (such as a leaking 50p seal) then there's a good chance that the head of oil above the turbo centre lines will gradually weep past the turbo seals.
I've replaced the broken injector connector, fitted a new fuel filter (the old one was date stamped 03.08 so likely the factory fit) and checked that the inlet manifold flaps work so now I'm stuck twiddling my thumbs while awaiting arrival of the injectors, manifold seals and a breather pipe to replace the one which decided to snap when I removed the lower manifolds.

[Jim Haseltine]

I had exactly the same issue, blue smoke at cold start, not every time the car was standing for a couple of hours, but maybe every 3-4 starts. Over two years it became worse until a day where I had substantial blue smoke on heavy acceleration and found more than 1.5 litre of oil in the intercoolers (more oil on the right). So I thought like you that the turbos are gone. I brought the car to a workshop, they pulled the engine and sent the turbos in for rebuild. When they started the engine for the first time everything was fine and also the first test drive of about 80 km was fine, but when the car was started after a weekend of non-use, it smoked like hell. They thought the rebuild was not correctly done, so they send the turbos a second time for rebuild. The company that did the rebuild did not find a problem with the turbos. After many days of searching for the failure mechanism, the workshop gave up and I had to find a solution for myself. To make a long story short: In the oil module there is a non-return valve that closes when the engine is not running. This valve in my case did not close properly and allowed oil to drain from the turbos to the intercoolers (before rebuild) or to the catalytic converters (after the rebuild) via the oil return lines of the turbos (the level of the oil tank is above the level of the turbos). To confirm this, I did two things: 1. I checked by dismounting the turbo oil return lines from the oil module if oil is flowing out of the module when the engine is off. In my case it did, up to a litre overnight 2. I used a clamp to block the oil return tube from one turbo, when the engine was off (I used the car only for short distances). I then start the engine on several days (of course with the clamp removed) and after a few days I had smoke only on the non-blocked side. I replaced the oil module and since then I had no smoke at all (was in 2018). I disassembled the oil module to have alook at the valve and it just looked fine. But it did not work properly. A perfect example how a 5 pound part can cause many sleepless nights ....

It's now very similar to this - one day it'll smoke quite badly on start up, nothing for the next couple of days then on the third day it smokes again. Sometimes it's short-lived, other times it'll smoke for a couple of miles. Oil level has dropped to about 5-10mm below the fill/don't fill line but if I top it up it smokes again the next day.
I've now got another couple of problems - firstly the oil level/temp sensor is iffy, sometimes it works, other times the dash reports it as defective and secondly I've had a couple of instances on non-starting over the last couple of weeks - this evening it took three or four starting attempts before the engine managed to pick up and run even though I'd already used the car a couple of times earlier in the day. There's also a suspicious dark patch appeared on my driveway which looks to be in about the place the nearside rear wheel usually is - tomorrow I'll be checking that the DRC hose isn't damaged before I take a look at the condition of the spark plugs.

[Jim Haseltine]

Oh marvelous. It's not the hose, it's the shock leaking from the piston rod seal. I don't use the car much at the moment and as the suspension is quiet and the car is still sitting level hopefully that can wait a while as I've other things to deal with.

[Jim Haseltine]

Another step in tracking the source of the smoke - probably heading sown a dead end but best to fix every broken thing I find....

Part 22 is listed as 'breather line'

it runs from the left air box to the left turbo oil drain and supplies air to the oil extract to stop too much oil being pulled from the turbo at high revs.
It's not just a breather - it has a non-return valve or should have - mine flows in both directions. According to one of the Audi technical videos a car that smokes on start up should be checked for a failed non-return valve - although it's likely to have oil in the air cleaner box, which mine hasn't and there appears to be no oil in the low pressure side of the intakes either.

[Jim Haseltine]

Half a litre of oil in the intercooler/turbo hoses this morning, can't be more than 2-3 weeks since I last drained them and the car has maybe covered 100 miles at most in that time. The failed non-return valve mentioned in my previous post has been sorted and I've put catch cans on the turbo inlets to see what drains out over night before taking the return lines off the oil module tomorrow.
I cleaned all the oil from the nearside rear shock and tyre on Wednesday, drove carefully some 5 miles or so on Thursday and everything is covered in oil again.

[Jim Haseltine]

Well, well. After 24 hours there was nothing from the left turbo and very little from the right. After another 24 the left was still dry and there was nothing more in the right. Pushed the intercooler hoses back on, ran the engine up to normal temperature (quite a bit of smoke which didn't smell of oil), took the hoses off again - left was dry, right had some drops of oil in it. Catch cans back in place for 24 hours, left was dry, right had a very small amount of oil in it. Repeated yesterday, similar results but slightly less oil in the tight pipe and (again) little in the right catch can so I hope I've sorted the left side (possibly the non-return valve). It's almost as if there's insufficient oil being scavenged from the right turbo.
I've had the right oil return lines off today and ensured that they aren't obstructed. Both return lines have been off the oil module and there's nothing leaking back from it.
I'm waiting for an oil level sensor to arrive - until then I'm going to keep fiddling in the hope that I eventually hit on what's behind the oil dripping in the right side.

[Caino6]

Are you sure it’s oil that it’s burning? Mine smokes a fair bit when not having been started for a few days, but it’s not oily, it’s darker in colour and smells like fuel.

[Jim Haseltine]

Some of it is condensation from short journeys but every three days or so it's been oily smoke. Confirmed by a mate who was enveloped in the cloud while he walked past one evening.

[IanH755]

Are you sure it’s oil that it’s burning? Mine smokes a fair bit when not having been started for a few days, but it’s not oily, it’s darker in colour and smells like fuel.

Maybe a sticky injector which takes a few seconds after starting up before it unsticks. Had a diesel Mondeo with 2 sticky injectors, very similar symptoms.

[Caino6]

Are you sure it’s oil that it’s burning? Mine smokes a fair bit when not having been started for a few days, but it’s not oily, it’s darker in colour and smells like fuel.

Maybe a sticky injector which takes a few seconds after starting up before it unsticks. Had a diesel Mondeo with 2 sticky injectors, very similar symptoms.

The fella from MRC mentioned injectors when I took it there for a health check on the dyno a few months ago when I said it’s a bit Smokey from cold. He didn’t seem too worried about it though. There were no trouble codes stored in the engine ecu. I think he said the only trouble code stored was something to do with an engine mount which again he didn’t seem overly worried about