WichitaWay

Hi! I have a 2012 GLK with 107,000 miles. I haven't had any issues prior to having oil leak out of my engine a week ago. It was a hot and humid day. The check coolant light had been on for a week or so, but when it has come on previously (once), the coolant wasn't too low, so I wasn't worried. After coming home and letting the car sit for 5 minutes or so, I moved it and it looked like about 3 T of oil had come out and was under the car on the driveway. I later had my son look at it. He noticed that the oil level was over max (engine was cool). Four months ago I had gotten an oil change at a regular mechanic, who I thought was reputable, for the first time (Carmax no longer wanted to work on non-Carmax cars). I did research and saw that overfilling a GLK can cause engine leaks. I drove the car for around 2 miles a few days later, and a small amount of oil came out when I was done driving.

I also had noticed in the weeks or months leading up to the this the fan in the engine area seemed a bit loud. But the temperature of the engine never went up (that I noticed).

My question is - what to do? I was going to take it to the dealer to have them diagnose it in case they feel the problem was caused by the overfilling by the other mechanic, and this would give me a professional testimony to use in case I have to pursue legal action. But, taking it to the dealer is expensive, and given the other issues (refill coolant, loud fan), maybe it isn't related to the overfilling at all. In this case, would it be better to just take it to a good foreign car garage? I could also just have the dealer diagnose it and then have it worked on by the other garage.

What would you do? Any ideas what the problem is? Thank you!

Mmr1

A dealer is the last place you need to go unless you don’t care about spending 3-4x more . Overfilling is with a lot of questions . It’s not so simple . How much was it to high? Was it checked like 5 times after sitting 30 minutes ? If not you do it because those dipsticks can be real tricky . In the morning mine shows empty! It’s fluid tension I believe. My 13 is always showing overfilled when I use the Correct amount ! By 1/2 qt! I thought it was just a bit of sludge in the pan from 15 year of use. Then I got an oil pan leak and had it removed and fixed , surprisingly, NO SLUDGE! So I thought maybe the wrong dipstick ! Well I broke my dipstick off trying to check it. A new dipstick was even WORSE! So I give up and just put in what MB says to put in. Your leaks ? Find it and fix it, get UV dye and a light if you can’t . But leaks are normal in old cars . What is the color of the oil? It is whiter or milky ? Now at 80000 my water pump is leaking and a few little oil leaks . But you don’t want milky oil, that’s a head gasket leak.

calder-cay

I've always done maintenance on our vehicles (autos and motorcycles now for 40 years). Wrenching has just been a hobby, plus saves money, and I know exactly what's been done.

Not long ago, our 2014 GLK350 Base had an oil leak. It was challenging to find the source leak.

Turns out, it was the o-ring gasket for the oil filter housing (up top front of engine) had gone bad. A new Mann filter and o-rings ... and the problem cured.

And, about a month ago, got a "low coolant level" message on the dash when I started the GLK. I turned the engine off, opened the hood and then the coolant reservoir.

Added about 1 oz of coolant (if that much) and the message went away. That's all it takes to turn on that warning.

WichitaWay

Thanks so much! I'm hoping my issue is also nothing serious :-).

WichitaWay

This helps so much - thank you. The oil is not milky, thank goodness. We will get the leak checked out!

calder-cay

I just remember that I created a thread detailing the oil leak issue, complete with a picture or two.

( My memory has gone mushy, since I retired over three years ago. ) Here's the link

https://mbworld.org/forums/glk-class...-not-good.html

habbyguy

Sounds like calder-cay's leak might have been different from mine. My 2011 (M272) developed the all-too-common leak from the oil filter / cooler housing seals, spreading lots of oil down the front of the engine on the left (driver's) side. Not a tough fix at all, though it's a little fiddly because of some of the other stuff you have to R&R to do the job...

WichitaWay

Thanks. The leak only occurs after driving, not while the car is just sitting. Could it still just be the oil filter housing seals or an o ring leaking? BTW, I am a female, and unfortunately I haven't delved into fixing my own cars yet :-) My son would help, but he is hours away. Luckily I do have a reasonable, skilled foreign auto mechanic in town. Thanks!

Mmr1

It’s a leak and you don’t know where it is or what is leaking , could be the transmission. You shouldn’t think you need a foreign car mechanic , just go to a mechanic your friends or neighbors find honest and competent . Take a flashlight and see if you can see where is is leaking

WichitaWay

It's oil. My son verified, and it's quite black.

John CC

Which GLK is this? Is it a Diesel engine?

calder-cay

Ours is the 2014 GLK350 Base with M276 engine V6 gas model.

Oil was leaking because that o-ring (see attachment) around the plastic oil filter housing was worn out.
The leak wasn't very noticeable, because it was leaking out the backside of the housing.

WichitaWay

No, GLK 350 4matic. . . It's weird that the oil was so black since we just had the oil changed, although perhaps this suggests the location of the leak?

Mmr1

It’s leaking because the gasket was reused, dirty oil could be your motor is dirty, do you go with the 8-9000 mile interval ? Once I had a reputable place change my oil, I checked it and it was black, they didn’t say anything but gave me my money back . Always check things yourself

John CC

Isn't there new one in the box with the filter?

Odd Piggy

There was always a new one in all the PurFlux, Mann, Mahle, MB filters. But I managed to pinch the new one on one of our Ford EcoBoost engines and it leaked like there was no o-ring there.

John CC

That's when you re-use the old one!

Different from "worn out", though...

habbyguy

One issue is that the very tight under-body splash panels (designed primarily to keep water and dirt out of the engine / chassis area) are really effective at holding the dripping oil for a long, long time before it starts dripping out.

If your problem is the oil cooler / filter housing, usually the left (driver's) side of the front of the engine will be wet and oily, pretty much from the centerline over. On mine (actually, both a 2011 4matic and 2012 base "project car") the right (passenger) side of the front of the engine was still pretty clean.

And those gaskets DO leak regularly, and can release a pretty healthy flow of oil. On my car, the engine was pretty clean prior to a road trip, and by the time I had driven about 3,000 miles, the left (driver's) side of the front of the engine was nasty, and there was a lot of oil dripping from everything from the engine rearward under the car. Embarrassingly , I noticed this filming a how-to video on swapping out the serpentine belt idler pulleys (showcasing my now-grungy engine in the process). ;-)

Even if you can't do the work yourself, or don't have a talented volunteer on call, you could scan the video to get an idea of what the mechanic would be doing for their money. It's honestly not a huge job, nor is it very likely to end in disaster. It didn't take me more than a few hours, and a lot of that (as always) was spent fiddling with the camera / lighting / redoing things to add clarity, etc.

John CC

Filming? What, Super 8?

calder-cay

Yes, I buy the Mann HU 7025z filter, which includes new o-rings.

I think "worn out" is a decent description. The outer portion of the o-ring, which mates with the aluminum (?) outer receptacle (what the oil filter housing screws into) ... became flat over time (heat and maybe pressure). So when I went to screw down the filter housing during the first leak discovery, I could fully tighten [seat] it by hand. Not so with a new
o-ring.

John CC

How old was the o-ring?

The design of a static o-ring joint provides that the pressure you are sealing against presses the o-ring farther into the sealing area. Only if the o-ring is damaged, or has hardened and taken a set and then been disassembled and reused will it leak. I.E. if it is flat and reused, the flat will no longer line up correctly. This is why it is always a good idea to replace an o-ring if it has been disassembled.

WichitaWay

I looked at the oil filter housing. It is dry, so I think the leak is coming from somewhere else. The oil was dripping from the front left of the vehicle. Thanks!

calder-cay

Not to beat this into the ground. With the engine Off, when I looked for a leak, it was NEVER obvious. The housing was dry.

It was when I started the GLK and let it run, did it show the slight oil dribble out. With the engine running, it produces the pressure to reveal ... when the engine is Off, no pressure.

I'm not saying our issue is your issue, but it's worth spending about 2-3 minutes to let the engine run and check ... I removed the top engine cover and the lower covers were off ... had I left the top cover in place, it would have been more challenging to find.

The key step is when the engine is under pressure.

I show where it was leaking slightly, in the following post, but you would NEVER know it unless the engine is running ... (and also check @habbyguy reply up above in this thread)

https://mbworld.org/forums/glk-class...ml#post8919209