Hi all,

these couple days I've been getting blue-ish smoke from the tailpipe. seems like it's only happening at low speed and low rpm. However I don't think there's any power loss. A forum member, AudiSportB5S4, suspected that it could be head gasket; I checked the oil and coolant this morning they look normal to me except the low oil level. I then filled up with oil and i noticed the sound of turbo (siren noise) got quieter, so weird. the smoke also seems to come out randomly now because i don't get the smoke yesterday in the evening until just now. does this sound like a turbo failure?
one thing i would like to point out is that when i get my exhaust installed on the lift, i noticed there were oil on the passenger side turbo itself. Could it be a lose oil supply/return line? i also see oil mark on the exhaust tip, the passenger side exhaust tip only.

could someone please help me to analyze what could be the problem?

thanks.

 

blue is burning oil, white-ish is blown turbo(s). I've only had my S4 a week so I'm too new to know what the cause might be, if it was a 1.8T I could probably tell you.

 

pass side leaking head gasket

 

Usually when a head gasket fails it will allow coolant to mix from the water passages in the head into the combustion chamber, get ignited and blow out as steam from the exhaust. If the coolant gets past the piston rings it can wash oil off the bearings and then you have a bigger problem then just a blown head gasket.

I don't think he has blown head gasket because it would run hot and misfire if he was dumping coolant into the combustion chamber.

Oil in the turbo could be a seal in the turbo leaking. Weather it's a complete failure or not I don't know. I also don't know how he's describing it how much smoke a little is.

 

it could be that your turbo itself is leaking oil...where the exhaust and intake side of the turbo meet...both of my turbos are leaking from that spot now because on high millage cars like mine (100,6xx) the oil lines can get old burnt oil in them and for some reason if that burt oil gets loose (happened to me when i got used ko3's just to get by until my ko4's get put in) can cause the gasket to fail inside the turbo. when im at high speed i dont notice anything but when i stop or slow down i can see white smoke coming out of the tail pipes. i dont notice any power loss, just embarrassing white smoke...at least this is what my audi guy and achtuning and vast performance said was probably wrong.

 

bump, anyone?

 

Pull your spark plugs & see how they look.
Then pull off your exhaust & see if there is oil in the downpipes

You say there is a turbo squeal noise? If so, chances are they are going.

 

i pulled the spark plugs out on the passenger side, they all look fine to me.
haven't had a chance to take off the exhaust, hopefully i can do that this weekend.

 

I'd advise a compression test to rule out burnt valves (seals)/head gasket etc since normally blue smoke just on leaving from a stop/idle is oil burning in the cylinders (typically engine wear).

If the compression checks out and the smoke really is blue then that would sound like somehow oil is getting in the cylinders and it's cause would have to be diagnosed...but I suppose there is a chance the oil is burning inside the turbo/downpipe/exhaust mani, but not sure based on my experience...