Massive muffler roaring noise + oil smoke
 

Car is relatively stock except for down-pipe and aftermarket muffler.

This morning I started the car up and after about 3 seconds massive amounts of oil-based smoke started to come from the tailpipe. At the very same instant the exhaust started to make a very, very loud roaring noise, almost as I imagine it might sound if there were no muffler all. The sound also seemed to resemble a huge, higher-than-normal- frequency foghorn, (i.e. it seems to be like some sort of oscillation, but I'm not sure because I don't want to leave it running very long until I get more information).

Some background: For about a year I have had a moderate amount of oil-based smoke coming out of the tailpipe on about every third start-up. It stops after a few minutes when the engine has warmed. A while back I did some diagnosis and confirmed it was a turbo oil leak by checking the Primary's boost outlet pipe and finding oil inside it, (quite different to the secondary pipe, which was relatively dry). The car has also been losing more oil than it should, assumed to be as a result of the same turbo oil leak, (note: there is no external oil leak).

Getting back to the current situation, my guess is that the turbo oil seal has suddenly decided to go out completely and, after the 3 seconds, the Primary turbo has spun up enough, (but with only little boost because the wastegate is still open), to allow a massive amount of oil to leak into either (1) the small amount of boosted air on start-up idle or (2) directly into the hot exhaust gas.

My question is "what is causing the loud noise?" I've checked that there is no leak in the muffler exhaust piping. I've not checked the down pipe/flange yet. However, the fact that it takes about 3 seconds before the noise starts tends to suggest it its not an exhaust system leak, and that, combined with the oil smoke, it is a massive oil leak within the turbo. On checking the oil, there is evidence that it has suddenly started using very much more oil than before, again suggesting the turbo leak has increased greatly.

I've tried starting it several times, and it does it every time. In fear of doing any greater damage I have not run it for more than a few seconds after the noise starts. I may try it one more time to see if there is normal or lower oil pressure. The idle seemed OK, (about 1200 RPM), or so, but not much different to the normal speed at start-up. Didn't seem to be idling roughly, but it's always difficult to tell for sure in the first few seconds after start-up.

Can anyone confirm my analysis or otherwise give me some ideas on the problem? I'm especially confused by the loud noise.

Thanks

Dave

can you take an audio clip of the noise and post it? I would imagine as long as you have plenty of oil in the car it wont hurt it to run it. IS the noise coming from the front or back of the car? It isnt your air pump or anything like that is it?

whats you vacuum reading?

also i dont mean to scare you or anything...but is this what it sounds like?

http://www.youtube.com/watch?v=oovnx...eature=related

your apex seal is broken :(

Not likely... :scratch:

I'm no expert on this, and I'm just guessing, but the sound symptoms sound like it's stuck in parallel (after transition) mode. As far as the oil smoke, I don't know how that relates.

Here's a troubleshooting link:
http://www.autosportracetech.com/RX-...leshooting.htm

The other thought - which may account for the smoke - is that something on the turbo housing has cracked or blown out, but I have no clue what that could be - I've not heard similar symptoms previously.

Been out of town for a few days but yesterday got back to the problem.

Thank you all for your suggestions and help.

Anyway, this is going to sound pretty stupid, but in the interests of somebody else sometime making the same mistake, I'm going to post it anyway!

The loud roaring noise is, in fact, coming from the rear Bose speakers! It's a low frequency very loud hum from both speakers, regardless of the volume control setting on the head unit. Honest, it really does come over like a "roaring" sound! In my defense (!!), I had never let the motor run long enough after start up to notice that the sound frequency had no relation to the engine speed! The fact that the noise took 3 seconds or so before it started, along with my known, (and deteriorating over time) turbo oil leak problem, made me jump to the conclusion that the noise was somehow connected with the turbo issue! Also because I was so focused on the turbo as the cause, I never even checked to see if the noise was there even without the engine running! The smoke appears to be just another of those "lots of smoke when I start up" situations that I have been getting for a while, (since the known turbo oil leak problem started), on about one in every in 5 or so start-ups. Just as before, it goes away once the engine starts getting warm.

There - I've 'fessed up! There's definitely a lesson to be learnt here!

I'm now chasing the Bose amp/speaker problem. Oh, and I still need to replace the turbos, sometime soon, I hope.

Once again, thanks to everone for all your help and sorry to waste your time

Dave