FlyNavy727

Hey all,

New here, and very close to being a GLC 4matic owner if all goes well over the next few days. Buying because I wanted a combination of comfort, luxury, fuel efficiency, and some zip. The vehicle I am likely buying is a 2018 GLC 300 4matic in Selenite Grey (which I love), black interior (would rather have the beige), brown wood trim. 41,000 miles. Considering this is on the lower end of the 10,000-15,000/yr average, anyone have any issues I should look out for in my final test drive? I've heard a bit about squealing brakes, but think that may have been directed more towards the 2016? Also considering adding running boards because the GLC does lack a bit in stature, and I'm thinking they may add a bit of bulk to the otherwise lean car.

Looking forward to hopefully joining the owner's club

no_mulligan

I chose 2020 and newer because MB changed the engine from M274 to M264. The M274 was prone to have P052e error code which meant a Positive crankcase valve failure costing $1300+. Happened at low mileage as well. Keep reading about this in another thread.

Jetfuture

I would see if you can find out the service records and see if the P052E code has tripped and the crankcase vent valve assembly was replaced already. If not, you are likely going to have that repair at some point. I have 2 dealers near me, and one quoted $1900 for the repair (a REAL nice dealership in a higher income zip) and the other is in a smaller town 30 minutes away and quoted $1450 (they only have 1 certified MB technician, but have always done fine work). I have had the repair done twice, once at 35,000 miles and covered under warranty. The only problem is that the repair was done just months before Mercedes-Benz redesigned the assembly. So, we had the old version still. Well, the code came up again 2 months ago at 58,000 miles and the car is now out of warranty. I contacted Mercedes-Benz of USA Corporate and filed a "post-warranty assistance" claim. They took about a month, but they eventually agreed to subsidize the repair, and we ended up getting the repair discounted $600. Keep in mind that when MB Corporate reviews these cases they will see if you bought your car new at a MB dealership and if you serviced the car at a dealership. If yes to both questions, it improves your chances of any "help".

The majority of people seem to have the problem in the colder winter months (we did). From my research, it seems that a lot of short trips in the cold where the engine oil does not have time to get up to full operating temperature can cause the vent to get iced over from an oil foam on the inside. It cracks the fragile diaphragm on the inside of the vent. My wife only drives about 10-12 minutes to work, and during my testing in the middle of our cold winters, it takes at least 15 minutes for the oil to get to full operating temperature. It was suggested from a friend that it may have helped to give the car "an Italian tune up" once a week or so to keep things cleaned out. My wife drives like a "cream puff". The new assembly on the engine now seems to have much more insulation on the hoses, and does not have the vent valve anymore. So, it shouldn't be an issue going forward.

If the 2018 you are looking at has the modified assembly, then you likely won't have any problems. If the car has 41,000, don't forget that the spark plugs are due to be changed every 50,000. That's likely a $300-$400 expense at a dealership. Other than that, the transmission fluid should be serviced at 60,000/6 years, which will cost between $650 and $900 at most dealerships.

I wouldn't worry about the brakes, as I believe starting in 2018 they had the redesigned pads and such. At worst, they have the old design brakes and you would need to get a brake job done. The old design pads always worked fine, they just squealed in the winter when you were backing up in sub-freezing temperatures. The pad supplier to MB redesigned the pads for the GLC twice over the years and they now don't have any chronic issues that I am aware of. We had the squealing on our 2016, and had the brakes replaced under warranty with the updated pads - been fine ever since.

Other than that, no big surprises to worry about. Yes, we've had other issues, but they are always one-off issues and not really chronic amongst the fleet. You will spend more maintaining a Mercedes-Benz properly than, say, a Toyota. But the pleasure you gain from driving the Mercedes-Benz is worth it to me (if you can afford that maintenance).

You have also probably read about a few cylinder failures on the forums that caused the entire engine to be replaced. It is not necessarily unusual to have any manufactured automobile have an engine that needs replaced after only a few years. It is exceedingly rare. I have a theory with this. I don't believe a run-stop engine that seems to be gaining in popularity with all manufacturers is necessarily good for an engine long-term. Yeah, MB puts a super beefy starter motor on the car, which can handle 5-10x the number of starts as a "normal" starter. But the most wear on an engine is during the start, when the oil has not been circulating around (and could be cold, if it's the first start). What I have decided to do is have an independent shop in Chicago disable the run-stop feature by making the button on the center console maintain it's memory after stopping the engine manually. We now just keep the button off all the time now, and the engine never stops while the car is stopped. I believe this will add to our particular engine's long-term reliability. The other thing I do is change the oil every 5,000 miles. Have you ever seen the oil after the recommended MB 10,000-mile change? It looks HORRIBLE! For the cost of an oil filter and some Mobil 1 synthetic oil, I just change the oil myself for about $60 on the 5,000's. I then have the dealer do their oil service on the 10,000's. I feel the combination of changing the oil more regularly and keeping the run-stop engine feature disabled (which one can also do by pressing the run-stop button after every initial start), I believe we will better our chance of not having a cylinder failure. These engines are literally in millions of cars now, as they were used extensively in the GLC300 and the C300's (perhaps others too? not sure). So MB is VERY familiar with any of the problems. The engine failures I don't believe have ever been common. The crankcase vent valve? Super common problem.

Buy the car and enjoy it! They are great cars if you take care of them.

mbglc321

I own a 2022, and as far as I know they have the same motor and the fuel efficiency its not there. I upgraded from a 2020 highlander, and the Toyota had better gas mileage plus it was regular gas.
Otherwise I love the car.

no_mulligan

2015 thru 2019 has M274 engine.
2020 to current has M264 engine.