Hi from Down Under. This is my first post and sadly a bit of a worried one. I bought my 2007 E63 in June this year and absolutely LOVE it. It's in incredible condition, been an ex-wedding car and in superb condition.

However...today driving on the highway and overtaking I noticed some mild hesitation throughout the revs. Didn't think much of it as it was so slight that I thought maybe my mind was playing tricks.
A little later I was just cruising along and suddenly the car was surging and felt like it was misfiring. It had a lack of power and was reluctant to accelerate. At this point I looked in my rear view mirror and saw CLOUDS OF SMOKE (blue oil smoke) billowing out behind the car out of my tailpipes. I instantly looked at the dash and saw a yellow engine light (the one behind where the clock is). I then quickly cycled through my computer display and saw the oil temp was 135 degrees celsius!!! (275F). The hesitation/misfiring/surging/lack of power as well as the smoke was still continuing at this point, so I slowed right down and pulled over where it somewhat shuddered to a slow and rough idle, with smoke still billowing out. I honestly thought that is it, the engine is toast and I have blown one of the piston rings.

Trouble was, I was miles from anywhere in the middle of the NT (if anyone knows Australia, this is not a good place to break down) with no phone reception. I thought perhaps I can limp it to a nearby town (Adelaide River) and then call for a tow truck there.
I got out, checked the oil level - it was down a bit so threw in a little over 1L and got it back up to the max F mark. I checked under the car for any leaks - none at all. Engine filler cap looked fine as did the dipstick, albeit with a burning smell - no froth or milkiness indicating any coolant/head gasket issues - and the coolant temps were still rock solid normal.

I got back in it, started it up - it shuddered to a start, the dashlights dimming as it turned over - and with clouds of smoke, and no check engine light or warning messages at all. In any other situation I would've stopped, but if I'd left the car there, it probably would be days before anyone could come out and pick it up - and who knows if it would have even been still there in one piece.

Started driving it, and the smoke continued as did the shuddering/misfiring/lack of power when I pulled away, however it rapidly improved. I sat it at 95km/h, as that way the engine oil temp stayed around 129-130 degrees and no more - if I sped up faster (i.e. 130km/h) they climbed, so I sat it at 95km/h and kept the engine oil temp at 129-130 and stable. No more smoke (that I could see) and the misfiring/lack of power seemed to have improved a lot (note: I was afraid to put the foot down and test it out - I drove it very gently - however it was very smooth as always sitting on cruise).

I made it the 120kms into Darwin, and got it into a carpark. The drive in to the city I had some traffic lights where I was stopped and pulling away - no smoke, no real power issues that I could feel however I was driving it VERY gently. Once parked up in Darwin I checked the oil - the level was great and it hadn't used any since I topped it up. Had it idling and stood at the exhaust - no smoke. Got in and gave it some big revs - revved very cleanly and no smoke. Kept turning it on and off and it was starting well and turning over well as the engine fired up each time.

So....have I done something catastrophic to this engine??

Or is it something such as a crankcase breather valve self-destructing or something to that effect, explaining all the sudden oil being burned off out the exhaust and the misfiring...which has now dramatically improved to being practically normal again?
I have had engines go on me before, and once they go...they tend to stay that way. Hence why I am perplexed as to how it genuinely seemed completely terminal...and yet now seems to be normal again (except for the very high oil temps - that is unchanged).

Curious to hear what the wise heads on this forum have to say?

 

UPDATE: Left it sit for four hours. Hopped in just now and fired it up. Started normally, and drove entirely normal...except for the giant cloud of smoke on startup that lasted for a second before dissipating. Took it for a 10-12 minute drive in traffic, and slowly but surely the oil temps were creeping back up...was 120 deg C and climbing when I shut it off. Aside from the oil temps and cloud of smoke on startup, the car drove perfect.

 

Get it scanned the code will be stored and will provide some helpful insight

 

What does your coolant level look like? Does your oil look normal in color?

Also the W204 C63 forum is probably a better place for M156 questions.

 

Coolant is all good. Level and appearance completely unchanged

 

Thanks, and being in such haste when I typed up the thread title, I typed M154...jeez

 

The last thing I would ever have done is keep driving after an event like that. You may well have really damaged something and repairs on these motors are not cheap.

 

Blue smoke is oil burning, potential rings or valve seals. Either way it’s not a good thing. Could be the pcv system. Hard to say now as the car s running fine, but you can always pull the oil cap when the problem is happening, if it’s very hard to remove you have a pcv issue

 

Im going to guess its a fuel related issue. The pump? dirty injectors? Do you all use ethanol in your fuel? That corn oil stuff really is bad. Don't we have a fuel pump, fuel leak warranty on our cars? The other issue could also be ignition, it isnt too hard to remove the plug and see what they look like. I think its a 1 hour job, but I would drive by someone with a OBD scanner and see what coeds you have logged. You can even use the cheap scanner from amazon.

 

Good news is the car is fine and back in good order. Turns out the radiator was shagged. There were four small holes on the side that had water coming out like a sprinkler...and straight into the air intake. The mechanic believes that the smoke and misfiring was from the water vaporising in the engine and out the exhaust. I disagree as it was definitely oil smoke and that can be confirmed by the burnt oil and the drop in oil level. However the mechanic believes it would have given codes if it had oil through the motor like I suspect.

I can't really explain how oil went into the engine, except that it may have something to do with the engine going into limp mode when the oil temp hit 135C right at that moment - I was doing 130km/h on the highway and going into limp mode obviously cut fuel and retarded timing etc causing the misfiring which then in turn potentially led to perhaps oil venting back from the crankcase - however that is just an assumption. Regardless, the engine is fine, oil level is perfect now and not using any. Compression is fine. And the PCV valve inspected and apparently that is fine too (I thought it could have ruptured leading to the oil burning off in the engine). Its nice to have the car back, $3400 later!

 

Wow that's alot ofcash for a radiator!!I guess mechanics are the same as in nz when they see a nice european brand pull in ;( at least you know it's good and healthy. Back to 130kmph with you!

 

$1200 for a genuine radiator, $450 for freight, coolant and pressure test costs, "diagnostics", all at $150 an hour labour! Got new oil and a filter in there too but yes....rather dear.

 

Could you tell what caused the radiator holes?

 

No idea. I believe it was split. Perhaps just age.