IAWMohror

Hey all, changed the oil in the GLK, (first oil change since owning it as I purchased it back in March), and I don't have any leaks or drips as it was a pretty straightforward oil change BUT, now I'm getting a weird smell from the passenger side back by the dipstick and I've noticed that the dipstick isn't staying seated at all. I wasn't having any of these issues before the oil change so I'm perplexed as to why they would creep up now.

I wouldn't say that the o-rings on the dipstick are tight by any means but they aren't completely toast either, more on the loose side when re-seating it but not an issue I noticed before the oil change. Also saw smoke one night in the headlight beams when I got home and it was idling before I pulled into the garage; every once in a while I'll get a weird smell when idling but it isn't consistent.

I've checked the oil and the coolant to make sure nothing is going on there and they both look like they should. Oil level might be a smidge high, maybe because I didn't do a vacuum oil change just a standard one? Any help would be appreciated!

Edit: I'll add that I put in exactly 7.5 quarts of oil as well.

karmikan

This is such an easy job, it's hard to think what could have gone wrong.
The dipstick not seating almost seems like excessive piston blow-by but it would be a huge coincidence for this to happen immediately after an oil change. Just to make sure start the engine and remove the oil filler cap, if you feel any appreciable venting you might have worn piston rings and bores. If the previous owner didn't service the car properly this could happen. What was the condition of the old oil?
Did you replace the O rings on the oil filter cap? Did you oil them before replacing the filter?

John CC

Could you have somehow affected the crankcase venting, so it is blocked, or pinched?

How high is "a smidge"? Whenever I change the oil, I add, for example, 7 quarts, run it for a few minutes, check for leaks, then top the level off using the dipstick as a gauge.

andreigbs

If it wasn't smoking/smelling before the oil change, something must've happened during the change that you may have neglected.

Some GLK350s only take 6.5L to refill (with new filter) while others are listed as 7L (see https://oil-change.info/mercedes-ben...-oil-capacity/). Mine holds a little over 6L but I never manage to get it bone dry since I do top-side extraction method. That's a topic for another day...

Point is, if you added 7.5L or more, you may have overfilled it since I'm sure it wasn't completely empty/dry even though you drained it.

I would also check the PCV system, all the air hoses that go to/from it. Did you make sure to NOT overtighten the oil filer housing cap? Replaced all the O-rings from the cap? That cap is plastic and can be damaged, causing leaks under pressure.

IAWMohror

I started it this morning and immediately went and pulled the oil cap off, while I didn't feel hardly any venting or excessive pressure, there was obviously oil all over my hand from it being right above the oil fill hole. The old oil was pretty dark, I'll see if I can upload a photo that I took of the old oil filter next to the new one. And I did replace all three o-rings, also lubing them before reinstalling the filter and cap.


Not that I'm aware of, honestly just did a 'by the book' oil change; removed the engine cover, removed the splash guard, let the oil drain while replacing the old filter, used a new crush washer and drain plug, refilled and was done. I'll have to check again to see where the oil level is sitting at.


I'll check the oil level and see if I need to drain some. I do have an extra quart just in case I drain too much. Kind of a ridiculous thing to have to do but oh well, I've never had a shop do my oil changes and I've never ran into an overfill issue before but there's a first time for everything. I did replace the o-rings, I marked where it was sitting before I took it off and made sure to tighten it back to the exact same spot, I checked it again this morning and there are no leaks or cracks around it, there aren't any leaks anywhere on the motor and nothing visible on the ground after sitting overnight or after driving the 25~ minutes to work.

NYCGLK

How many miles?
7.5 sounds about right. I try not to overfill and stay in the middle of the dipstick.
Dipstick should seat pretty tightly. I recall there is almost a "click" to it.
Is it possible you simply didn't seat the dipstick all the way and some oil spewed onto the exhaust manifold? Check for leaks/seepage around valve covers.

IAWMohror

133k miles. I don't get any click or tightness in seating the dipstick, it just slides in and stops when the green handle hits the tube. No leaks around the valve covers at all.


So I replied to everyone else about a day ago and it said that my post needed moderator approval and hasnt shown up at all, not sure what's going on with that ...

NYCGLK

Yea I mean it slides easy but should stay there. I doubt it's the issue. So when you say weird smell, you mean oil smell or some other smell? Where is the smell? Outside or inside of the car? The cabin filter is on pass side, and there were some issues with HVAC smell.

Mmr1

My 13 takes less oil than listed at about 6.5 qt, I drain it all out. Overfilling causes increased pressure. I also find checking the oil can be more difficult if it’s full , check it a few times after it sits for at least 30 minutes

IAWMohror

So I checked the oil yesterday and it's sitting just below the max fill line, seems like a good place for it to be at. This morning coming into work I was sitting at a light after I got off the freeway and it started smoking out of that same place again; finished the drive to work and popped the hood and it was still smoking off the passenger side between the engine and the firewall, right where the exhaust and heat shield are. I used a flashlight and still can't find any visible drips. Tonight when I get home I think I'm going to pop all the plastic engine covers and take a better look, also check the PCV system like was mentioned.

I'm not getting any dash lights or overheating, it's not running funny and gas mileage is the same as it's always been. I might pull the plugs and check those too, see if there's any oil on them or if anything looks weird.

andreigbs

Pulling plugs will be close to pulling our hairs out, so I'd suggest leaving that as a last resort. But definitely remove plastic covers and see where the smoke may be rising from. It could be something simple as in you spilled some when filling, and it leaked to a lower point that gets hot when the engine is running.

Or it might be something with the PCV, which shouldn't be acting up just because you changed the oil. I understand how frustrating it can be when you complete a simple job and find yourself with a new problem that shouldn't exist. Good luck!

IAWMohror

Mine should be the M272, right; which has the easier to access spark plugs?

Either way, I think I tracked it down. Whoever mentioned the PCV, looks like you might be correct. I stuck my hand back there and under the PCV and sure enough, there was some wet oil back there and it's right above the exhaust on that side. Ordered this little kit off of FCP: https://www.fcpeuro.com/products/mer...es-2720100631k , to go ahead and hopefully fix this issue. Looks to be pretty easy to do as well. Thinking this might solve the dipstick problem and also a rough idle issue, (although the rough idle could be mounts still, I can be hopeful.)

Thinking the cause behind this happening after the oil change was that the oil was so dirty and Lord only knows what kind that it wasn't seeping out of the PCV, but when I put the correct, fresh, thinner synthetic in, it started leaking. We'll see if this fixes it when the parts come in.

hceptj

I did the plugs in my 2010 in about an hour...super easy.

Hopefully that pcv fix works for you 👍

IAWMohror

So I did the PCV and all three plugs in about an hour yesterday, seems to have fixed the leaking and smell/smoke issue so far, the old PCV gasket was flat as flat can be. I will say that the lower left most passenger side bolt is a huge PITA being that close to the firewall.

While it did fix all of that, I thought it might fix a rough idle issue too but it hasn't. I know these are notorious for having mounts go bad, should I look into that first or is there anything else I can check before that daunting task?

John CC

andreigbs

All 3 on same side? Because I'm pretty sure there should be 6 sparkplugs, 3 on each side.

Good job on replacing the PCV. While you monitor for the rough idle issue, doublecheck that you're not leaking/losing any oil as before.

Engine mounts on a 4Matic are a PITA, no getting around it. If you need it done, it will make a world of difference. But only if the original(s) have failed. Otherwise try some fuel injector cleaner and run premium fuel.

IAWMohror

Haha, sorry guys, I meant the cam/expansion plugs on the rear of the engine, I should've clarified better.

IAWMohror

I warmed it up and ran it around briefly yesterday and didn't see or feel any oil leaks at all so that's a good sign, I'll check again today when I get home. Premium is the only fuel I run in it, there's quite a few places where I can get 92 up here so that's what I always try and shoot for.

John CC

Well. that clears things up. Previous posts mention rough idle and changing (spark) plugs, something that makes sense if you're chasing a poor idle. I didn't want to be the one to point out that there is one for each cylinder.... "Gee, I never looked at the other side..."

andreigbs

If fueling isn't the issue, then the next step is inspecting the motor mounts. I believe the OE ones are liquid-filled, so if any of them is broken you should see leaking/dried residue.

fricker66

Interesting as I am now chasing a similar oil smell following an oil change. Will def take a look at the PCV and report back. Appreciate the detailed discussions here in this post!

IAWMohror

Should be able to reach around the back side of the engine from the top passenger side, feel the PCV and run your fingers around it. If it's leaking you'll have oil on your fingers.

Mmr1

To tell if it’s the pvc lift up on the oil cap when motor is running, if it sucks thd cap back down with force the pvc is bad, vacuum gauge should be used to measure the actual vacume
my 13 at 75000 miles , I had the pvc replaced , another expensive mb job because the dumb *** engineers did not make it an easy job. It’s way in back and about 5-6 hours work . They could have put the unit in front , or even simpler, remember the American 5 second pvc replace ! The little metal shakers ! No MB makes it as hard as they can, and the cost of the unit is another joke.

fricker66

Yeah its the PCV. Ordered a replacement unit and kit from FCP Euro. Looks like some garage time for me in the near future...

Mmr1

The mb pvc units fail at the connection, they leak , poor design