Hi all, it has been a long time. My '08 R56 has been in my garage for well over a year since it started blowing blueish smoke out the back. Now I'm about to undertake the job of fixing it. My question to you is: how do I trouble shoot the root cause of the smoke?

The situation: I have spent quite a bit of time and money upgrading my Mini over the years, so I'll identify the relevant changes. But first, the act that caused the smoke. I had just changed my thermostat, but the car was still getting a little hotter than normal, so I scheduled an appointment with the dealer. On the way one of the hoses blew off, the car drained of antifreeze and quickly overheated. Stupid me, I pushed that last mile to the dealer. They resolved the coolant temp issue, but on the drive home I noticed blueish white smoke out the back. It smells like burning oil and it only blows the smoke after I sit at a light or stop sign and then I accelerate. A big puff of smoke comes out when I go. It doesn't appear to be smoking when I idle, it is just when I take off. I don't see it when I drive either, but I also haven't had anyone following me to check in more detail. This went on for a month or two before I put the car away to be dealt with another day. I didn't want to make it worse.

As for the modifications, these were all several years ago and the car had been running great up to this point: Alta Accessport (stage 3), Milltek catless turbo back exhaust, Alta Performance intercooler, tighter BOV valve spring, turbo heat wrap, replaced the turbo oil in-line and the manifold gasket, installed turbo oil heat shield, I've done a seafoam treatment. That's all I can think of at the moment. I think my signature is outdated.

I do have seepage around the cylinder head cover, so I know I need to replace that. I also have to do the timing chain, so I'm going to have the whole engine bay in pieces at some point when it comes to everything I need to do. However, I don't want to replace a cylinder head when the blue smoke is actually coming from the turbo, or vise versa.

Any tips for trying to figure out what the culprit is? What do I look for under the cylinder head cover? How can i diagnose if it is the turbo? So many questions. I like fixing things, but the reason I'm not a mechanic is that I'm terrible at diagnosing them

Thanks!

 

My 2010 MCS had the same symptoms. Turned out the piston rings in cylinder 4 were shot. Previous owner most likely ran it low on oil and did infrequent oil changes. Lucky for me it the car had CPO extended warranty from MINI. Only had 55k miles..

 

Sounds to me like you overheated the engine and the rings lost their temper - hence, oil usage.

The fix is to pull the engine and do (at least) rings. While you're in there, an 08 can probably use a general tuning up and cleaning up the valves and seats would make sense. Check bearings and replace if needed.

This is a very expensive mistake to make...as is now clear.

Option: drive it, feed it oil as needed, and don't worry about it. it's not likely to get any worse soon, it just won't get any better.

 

Agree with Colo, the rings are probably shot. Over heating will do that quickly. To be sure, get a compression and leak down test done. Should give you a good idea what you're up against.

 

Yes, do a compression test. If you're really lucky, it could be valve guide seals.

I think it is terrible that you drove it a mile after losing the coolant, what were you thinking! That mile will probably cost you a bunch.

 

In my case smoke only at lights after spending a bunch of money thinking oh if I do this or that will stop the problems pcv valve cover and bunch of other stuff loosing oil every 700miles like crazy.
So turns out to be bad valve seals but only after they pulled the head to also check for valve guide so 2000+ later with head rebuilt the car now is a dream to drive,at 58000 miles on odor and I am the second owner of this 2009 mcs it turned out to have a serusly bad carbon buildup wich they also cleaned, no more smoke and the catch can is doing its job to keep as much carbon out of the motor as posible,so you may just go start looking at your valve seals first. My 2c after spending bunch trying to fix the smoke problem.
Ben

 

Thanks for the great feedback everyone! Trust me, I'm kicking myself every day for that mile. The tow would have been $100. The repair...well, much more than that in both time and money.

I'll do the compression check. I don't know why I didn't think of that first. Like I said, I'm terrible at diagnosing. There's just so many other things going on with it and so much information out there that it is easy to get caught up thinking you have the same problem as someone else when you don't.

I'll return in a month or two with an update. Thanks for all the input!