Tom4743

GLC300 2016 billowing white smoke. 45K miles. 8mo out of warranty. All service done by MB but one oil change done by me. No noise from engine. No CEL's. At cold it is fine. Once warmed up and at take off, it billows out white smoke engulfing whatever car is behind me. Pulled over immediately and white smoke from tailpipe. Drove 1 mile to local shop and next day towed to MB. Both shops initially drove the SUV and had no issue. Both shops drove again (I assume after car was warmed up) and experienced same billowing smoke issue. Dealer saying could be cracked block, head warped or bad gasket. Won't know until it is dismantled for $$$$. Going higher up food chain at MB as it is not long out of warranty and clearly not the life expectancy one would expect out of my 3rd MB.

Teckno

Have you a Turbo in your model ??? Was smoke during acceleration or during back-off slowing down ? Any water bubbles coming from coolant bottle or was oil on dipstick white, milk looking ??
Good luck. Keep us informed.

chassis

White “smoke” is either oil or coolant.

What did it smell like?

Could be cracked piston, lots of that reported on GLC, E and C class vehicles with M274 engine as you have in your 2016.

Failed cylinder head gasket, cracked block or head are also possible but not often reported on this site.

karmikan

Both the above are good suggestions except that burning oil tends to have a slightly blueish tint.
I would urge you to insist the dealership shows you the problem part before you make a decision on a course of action. It's not unknown for a dealership to overstate issues for the benefit of their bottom line.

Teckno

Any update ?
Could the oil have been filled twice by mechanic and apprentice ? Or not filled at all because they thought the other did ?

Tom4743

Update. Dealer report low compression cylinder 1. The first of several possible causes he said it could be was cracked piston. Very odd that that was the first suggested possible cause spoken instead of blown head gasket. Dealer says, need to tear down to figure it out for sure and it could be anywhere from 14K to fix to 24K if new engine is needed. Thanks for the forum responses as they lead me to research and find the piston issue continuing to happen. MB corporate said out of warranty no exception will be considered. Pleading case but now corporate is not returning my call. I am afraid exception request will still be no. Dealer is being somewhat supportive and offering to buy the car for 13K. Considering doing that instead of having them repair. Up until now I viewed MB as the best build cars on the road. I am 53 and figured I would own many more of them but with the lack of any consideration of an exception by MB corporate I am afraid this will be my last ever purchase. So sad. Still hope it doesn't come to that.

chassis

Sorry to hear of the experience. Nice option to consider that the dealer offered to buy the vehicle. Probably the best choice.

The M274 engine is becoming well known for piston cracking. Unclear yet if the related M264 engine is also affected.

MB has not been a quality manufacturer since the 1980s with the 300D. MB is globally known in most markets to produce low quality garbage.

Tom4743

Update. Talked to MB corporate rep again regarding exception. Answer is still no for any type of support or further review. Very disappointed at this side of the outcome. Settled on the dealer's option to purchase the vehicle instead of us dumping an unknown amount of cash into it. Since we didn't have the engine torn down, I can't say for sure it was the piston but given reading posts, dealer report low compression cylinder 1 and by the looks of the black soot on the tailpipes when we went to finalize the buyback it does seem plausible. I hope this goes to class action one day although I may not get anything from it since we no longer own it. To those with models having similar engine, I would recommend extending your warranty if you plan to keep and pay attention for issues on the forums about your model. Our 2016 GLC had the M274 with Turbo manufactured March 2016 in Bremen, Germany. Another post by someone else is titled "GLC 300 Engine failure".
When we left the dealer we were both sad, disappointed and a bit angry with MB. My wife really loved the GLC more than any car we have ever owned.

W205C43PFL

You probably would still get compensation if it does become a lawsuit, for example the prior BlueTec lawsuit owners still got compensated despite not actually owning the vehicle anymore.

Camaroguy72

Very sorry to hear the misfortune !

Do you mind sharing the entire service history of the vehicle ? Really would like to see what was done and when, as well as what brand and grade of fuel you’ve been using for the most part.

Tom4743

Bought it as a CPO with 22K miles. It was a one owner lease turn in. Car fax shows all dealer service records. Dealer services prior to our purchase and we had dealer do next service at 32k miles as well as tires and back up battery replaced. I replaced the regular battery a few months later. A7 came op next at 42k miles which I had done the oil change with dealer bought filter and recommended Mobil 1 synthetic. Chevron 91 octane is primary gas used.

Xbowguy

Tom that stinks Sorry for your troubles I got 18 mo. warranty left on my 2019 GLC suv... I'm trading it in around the same time I'm going back to Lexus RX350 hope to fine a CPO low mileage then..

Camaroguy72

how much oil did you put in? And was the level to the top of the dipstick ?

Highline-Autos.com

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