Blue Exhaust smoke on start up.

-Ju-

-Ju-

Well-Known Member
VCDS Map User
Joined
Jul 22, 2007
Messages
3,858
Reaction score
1,662
Points
113
Location
Yorkshire
I hope people don't mind me posting this here as I have a 2016 RSQ3, but the problem is relevant to the 8P RS3.

The car has been using oil, not a lot, but over the last couple of years it's been significant enough to cause concern.

I did notice recently that it smokes a little on cold startup for a few seconds, and also after being left for a while once warm. Once that clears through afaik it doesn't do it. My first thought is valve stem oil seals.
20250531 1250175

I did have a leak under the turbo inlet that was looked at by Bradford Audi last year and although improved, it is still there slightly. Im not sure if this is related.
20240330 162646


I also recently replaced the pcv valve on top of the cam cover and on inspection it did have a small split in the diagram....bingo I thought, but it still does it
1000019805


I have done a compression test on the cylinders and they are all within 5psi of each other and strong (200-205psi) so I don't think its rings.

The car does occasionally feel very slightly lumpy on tickover but other than that it drives really nice and pulls well.

The car is APR stage 1 (done 2 years ago) and has 44k on the clock.

Anyone have any ideas of where to look?
 

Attachments

  • 20250531_125017(5).jpg
    20250531_125017(5).jpg
    934.8 KB · Views: 27
IMHO it is not getting past the rings, most common problem is the oil getting past the turbo bearing. I would check to see if you have any oil in the intercooler pipe.

Turbo is hardest on the oil because of pressures and temps. The turbo can knacker the oil then the bad oil can take out the engine.
 
  • Like
Reactions: -Ju-
Thanks for the reply.

I did wonder if the turbo was worth a look, would that lead to oil collecting in the pipe and giving that puff of blue on startup?

It's never been abused (or at least in the last 5 years) and it's had oil changes every 4-5k

Should there be a small amount in the inlet pipe?
 
Also would the turbo tie in with the oil leak around the inlet. It was quite bad before they "fixed" it!

I'd have a look under today but I've busted my knee and the wife would kill me lol
 

Attachments

  • 20240330_150148.jpg
    20240330_150148.jpg
    1.9 MB · Views: 24
Yes, if oil is leaking into the turbo, it can pool in the inlet (via the intercooler) or in the exhaust, sometimes both. I would check the turbo for play and the intercooler pipe or turbo outlet for oil.

Only takes one time for the turbo bearing to go

Good luck :icon thumright:
 
Ok thanks for your help, I'll try the pipe one night this week. :icon thumright:
 
  • Like
Reactions: flybynite
Ok so I had chance to get under the car today and remove the turbo pipe.

The pipe was fine, nothing to see. However both the rubber pipes at each end of the intercooler pipe did have a fair bit of oil sat in there.
1000020809


1000020808


1000020810


1000020815


I called in at the place that did the map 2 years ago and he recommended an oil flush and change, and to send a sample of oil off for analysis so I've ordered that
 
  • Like
Reactions: flybynite
dave_beastttt said:
What oil weight do you use?
Click to expand...
As in grade?

I use the standard 5w30 castrol edge. The car isn't driven to anywhere near its potential and its mainly short 2 mile there and back trips tbh, which is the problem

I've flushed it and changed the oil ......no difference. Just waiting for a sample kit from millers to send that off.

I'm thinking it must be the turbo?
 
I would try 5w40 to see if there's any improvement, it does sound like the turbo seal, if it only happens at startup, it's clearing residual oil that has leaked when the turbo has cooled down.
 
  • Like
Reactions: -Ju-
dave_beastttt said:
I would try 5w40 to see if there's any improvement, it does sound like the turbo seal, if it only happens at startup, it's clearing residual oil that has leaked when the turbo has cooled down.
Click to expand...
Afaik its only at startup. I need to book a slot with my son to follow behind and check lol

I think I'm just going to monitor the oil level for a while and see what happens, but next step will be turbo investigation I guess.
 
High Ju a few things to try, different engine i know but
Drain the oil out of the intercooler and pipes. I actually just put a new intercooler on and got 25bhp more instantly , they do fill with oil over time
My S3 started to smoke at about 80k miles when it was booted and i now use Mobil1 5/50 and its on a 142k and doesnt smoke and uses less than a litre per 10k miles.
Never put a flushing oil through a higher milage engine. its not needed if you use modern detergent oils and a bit of build up round pistons and bearings is not a bad thing as they wear and at higher milage.
 
paddy said:
High Ju a few things to try, different engine i know but
Drain the oil out of the intercooler and pipes. I actually just put a new intercooler on and got 25bhp more instantly , they do fill with oil over time
My S3 started to smoke at about 80k miles when it was booted and i now use Mobil1 5/50 and its on a 142k and doesnt smoke and uses less than a litre per 10k miles.
Never put a flushing oil through a higher milage engine. its not needed if you use modern detergent oils and a bit of build up round pistons and bearings is not a bad thing as they wear and at higher milage.
Click to expand...
Hi Paddy, High mileage lol....its done 44k....2016.
I asked the same question over the flush as i've always been hesitant over them, but they said it liquefied everything and is something they do all the time. It was Millers EPP that was used and they are respected. Add it into a warmed up engine and run on a fast idle for 20 mins before changing the oil. Anyway its made no difference that I can tell!

I did wonder if it was residual oil in the pipes and cooler, so I guess time will tell on the dipstick with that one.

I have kept up with the Audi warranty but I guess any sniff of a modification and its goodnight Vienna on that one.
 
Sorry i replied to another thread and the guy had done 80k. got mixed up :)
I remember back in the day when we all had 8p's some drank oil and some didnt and the quoted Audi acceptable limit was 1L per 1k miles. which really equates to a total loss system :) My thinking is that manufacturers use the thinnest oil possible in everything to get the MPG up. Its ok if their machining tolerances are spot on but in my experience, oil bypass is as much about way to thin oil as it is about any wear especially once everything has bedded in.
Hope you get it sorted
 
You must log in or register to reply here.
Top
Back