JBJ7457

Took it to service as sometimes its real loud and sometimes not, dealer said its due to the direct injection. Anyone else have a loud engine noise?

Thanks as other than that car is nice.

Jeff

ItalianJoe1

When is it loud?

These engines are actually terribly noisy, I have done a couple sets of pistons in the early ones for noise and often, after they're done, I think there's something wrong because it sounds like a sewing machine chopping away under the hood, but once I get all the covers back on and windows up, you can't hear it from inside the car. Sadly they are all like this, nature of the engine.

ajmtbm

there is thread on this elsewhere. typical of direct injection to be loud. agreed cant hear it at all inside.

brady

My 2018 GLC 300 seems a bit loud as well. A diesel-powered sewing machine is the perfect description. Odd, but I'm not really concerned for some reason.

Sigp232

When I first picked up my car on 12/16 drove home and let it idle on driveway thought they had put a 4 cylinder diesel engine by mistake with the rattling in engine bay. Reminded me of my Passat diesel(48mpg wow I miss it).
But after awhile you get used to the noise and will sound perfectly normal.

dieseldoc

All of my direct injection cars sound like diesels.

MBCA

Yup! Sounds like a diesel truck.

openwheelracing

Make sure you all use Keropur as fuel additive to make sure injectors are clean.

MBCA

Do you need that fuel additive if the car is brand new? I only use the highest octane fuel.

openwheelracing

Welcome to direct injection. I would use it once every 5K, some do it more frequently. Yes, even when new. I would start at 5K so it is easy to remember. I wouldn't wait until the 10k oil change. It is not just for injectors, but hopefully it helps with carbon deposits on the intake valves (long shot).

MBCA

Thanks. This is my first MB with direct injection. Both previous MB vehicles had V6 engines which I miss.

protseng

what do u think of redline:

peet

Most additives are snake oil. RE: they do nothing. Drive it as intended in the manual 91 octane (US), and enjoy it. Nothing you add will help it. As a direct injection owner of multiple cars over the years, there is one massive issue that many have still not dealt with and that is that by injecting into the cylinder, the manifold only gets the recirculated gasses and clean air and gets gunky. Some cars deal with this by combining direct with manifold injection. But it's rare. Typically what this means is that around 50k miles, your intake manifolds are covered in carbon build up. My older E90 BMW 335 had this issue and the fix was to take it to the shop, they had a rig to put on it that basically used sandblasting technology but used walnut shells as the media to clean it. The difference before and after (feel and what it looked like in there) was night and day. But there is nothing you can pour into a gas tank that will prevent that.

However, many have sworn by adding Techron every 5-10 fill ups. I used to do that, though in the end still needed walnut blasting and on that car, 4 new injectors (of 6).

ItalianJoe1

The V6 after 2012 is direct injection also. The way of the future, but yes the Piezo injectors are noisy. In the car you can't hear them though.

MBCA

You're right. I had a M276 engine. It was V6 with direct injection/Piezo. I wonder why it was so much more quiet than what I have now?

openwheelracing

Fuel additives are not “snake oil”. Try argue that with engineers behind Shell V Power and Chevron Techron, or better yet, Mercedes and Keropur.

In the era of GDI, it is vital to keep the injectors in top shape. You certainly don’t need to and your car will most likely feel the same. For me, I rather follow Mercedes recommendation with Keropur. They Use it at service intervals, and since I service my own GLC, I don’t mind forking over the pocket change. Certainly don’t want to wait til 50K to walnut blast and feel a “night and day” difference.

openwheelracing

ItalianJoe1

Mostly because of the large plastic plenum and insulation over the injectors. The 4 cyl doesn't have anything like that, just the engine cover.

will4iron

I agree.

will4iron

All direct injection engines sound like that. My daughter drives 2015 Hyundai Elantra with GDI(Gasoline Direct Injection) engine and it sounds exactly like mine. Diesel engine sound. I don't like tho.

mtberman

Not to pile on but Yes, fuel injectors in your DI engine operate under extreme pressure and are loud. In my experience the noise in most DI cars is particularly loud after a cold start, when the injectors are pushing a lot of gasoline in order to produce the super-heated exhaust that's needed to light up the catalytic converter. My Audi and Subaru would both quiet down noticeably as soon as the cat was warmed.