Celicasaur

I was driving across the country today on the highway and after a 130 miles or so (and in slow but moving traffic) i noticed some faint white smoke come out from where the side of the hood meets the wing. This was also paired with a distinct burning smell.

I popped the hood and checked and could see a very light amount of white smoke (mostly very faint) coming from the right-bank of the engine (right side if you're looking at the engine from the front of the car) from between the engine and the inner wing/chassis.

After about half hour this happened again (well, the smell came back, but I couldn't be bothered to stop again) and once I'd gotten to my destination and done my thing, after i'd set off driving again, when i got to slower speeds (where the smoke wouldn't have a chance to pool up and get stronger) i could smell it again.

I don't thinkkkkkk it's a sweet/coolant smell. But it's not exactly burning rubber either. Coolant and oil levels are at their normal high level.

I'm a little spooked. It's the first time I've noticed this and I'm planning a road trip to Switzerland from London in early October...I'm a bit paranoid now. I think a visit to Eurocharged is on the cards...

Anybody heard of a similar issue to this? I'm starting to wonder if I should just get them to change the headbolts for me, for peace of mind to rule that out of the equation.


On a side note - the W212 AMG is a brilliant long distance cruiser and what it lacks in very high hp tunability as found in the E55, it makes up for with easily by handling so much better and being so much more refined. I love it

Vrodman

It sounds a lot like a simple valve cover oil leak onto the exhaust manifold. Oil on exhaust manifolds smokes white and has a very distinctive smell. If this is all that is wrong, you don't have a lot to worry about.

Just make sure your oil level is OK.

When your trip is done, get it into the dealer and have your valve cover gasket replaced.

Good Luck.

PeterUbers

Hmmmm.... Head bolts???

Celicasaur

Phew, so thankfully Vrod was right - it was a minor valve cover leak which i appear to have been able to have fixed myself

I took pics of the process because i wanted to make a thread of it...but greasy fingers and the fact that I forgot halfway through, kinda ruined that idea.

So i did the basic job of cleaning the surfaces to make them nice and dry...and then applied some simple RTV sealant (same stuff i used to cure the valve cover leak on my E55, funnily enough) to the outer edges of the head surface and put it all back together.

The car must have had this slow leak for some time because when I took it for a drive, it instantly felt more alive and it feels a lot stronger in M and S+, particularly at light/mid throttle in the lower gears. I guess the gasket leak also made a vacuum leak and must have made it run slightly lean, or what not.

Also and more importantly - some very good news. My engine has the revised headbolts









Could only take pics of the top side for obvious reasons, but I was so happy to see them - i was actually going to call eurocharged uk and have them replaced as preventative maintenance, but no need to do it now. I'm so relieved to know that it has them and I'm sure it'll only help me with the resale of the car if and when that day comes.

PeterUbers

You rock!!! Well done, I wish I had your skills

Celicasaur

Thanks man

There really was barely any skill needed to do it though bro. Anyone can with a bit of patience and time. I say patience, because access to the lower bots near the firewall are a real PITA and even with my tiny hands I was struggling. Aside from that, I don't see why anybody couldn't do it. Might be worth others checking for small leaks down from the valve cover...the restored performance makes it well worth it!

shardul

iTrader: (1)

are those hot spots on the cam lobes normal?

Celicasaur

Probably not...but I'm not going to change them unless they fail. I looked at them and thought, urgh...

FWIW there wasn't any tangible wear that i could feel with my fingers, so I'll just turn a blind eye to it seeing as it all works well for the moment.

Vrodman

So on one hand I am happy that I was right about the valve cover leak.

But on the other hand, and I don't mean to rain on your excitement, I very much doubt that you gained any performance at all from fixing the leak. It might just be placebo. And furthermore, I feel like some days my car hauls ***, and other days it seems slower. It is in my head.

If you think about your theory of solving a vacuum leak, then oil leaking out would be unlikely. There should not be vacuum under the valve covers. If there were, you would be sucking in air through the leak instead of blowing oil out of the leak.

Now if you did indeed gain performance after doing this, I would predict that you fixed something else during the process without realizing it. Like a vacuum line or something. Then again, if you had a vacuum line leak, you should have felt it in the way of a rough idle.

My thoughts on this.

Glad you found the issue and fixed it though.

Celicasaur

I'm pretty positive that an air leak on a valve cover would create leaner engine conditions - bear in mind that when the valves open and the piston is going downwards sucking the air in, it'll pull air from every which way, even the slight unmetered air in my particular example.

Oddly enough, yes my idle is smoother now (i was thinking that today) and the placebo thing...tbh i wasn't actually expecting any restored performance at all tbh. It caught me off-guard when I went half throttle in manual mode on the lower gears. It's more tail-happy and exciting now too.

lol don't worry bro, i'm not some kid who gets excited at any kind of intake or exhaust mod. I actually know how to build engines, tune standalone ecu's and fix many common problems on my own cars

It's good to hear your thoughts though. This forum in particular has a very small following for the M156, so it's nice to see comments, even if they're not always in agreement.

otakki

It's good to hear you have fixed it yourself. I certainly hope I can open up the valve cover like that. Nowadays, it's so tight there in the engine compartment it's nearly impossible to stick any tools anywhere.
Must be a relief to see the updated bolts. I thought the cams are also updated if you have the updated bolts. Yes, just a few followers for the M156. It's too bad MB didn't decide to just forced induced the 6.2.

EMR2004

Can you share the process? About to do it on my car. No leaks yet. Doing it as preventative maintenance.
Thanks