Bad Pcv valve ?
Thread Starter
MBWorld Fanatic!
Joined: Sep 2015
Posts: 2,605
Likes: 347
2013 glk 350
Bad Pcv valve ?
A mechanic removed my oil filler cap with motor running , he showed me there was suction pulling it back down, he said it’s a bad PCV valve . Is this true ? I have no smoke or other symptom, oil changed at 5000m but bought used at 37000 miles. It has over 75000 now, I have changed the oil but I don’t know about previous owner. It makes no noise , maybe intake gasket ?
I see nothing in the Glk maintenance manual on even checking the PCV valve going out to 140,000 miles. I’m getting it replaced today.
I see nothing in the Glk maintenance manual on even checking the PCV valve going out to 140,000 miles. I’m getting it replaced today.
Last edited by Mmr1; Mar 15, 2023 at 05:50 AM.
MBWorld Fanatic!
Joined: Jun 2021
Posts: 1,970
Likes: 534
From: New Hampsha
'17 GLS450, '14 GLK250, Grandpa's Roadster
Depends. A little suction is a good thing; it helps prevent leaks. A lot of suction is not so good; it can suck dirt past the seals and increase oil consumption.
There should be no positive pressure.
There should be no positive pressure.
MBWorld Fanatic!
Joined: Sep 2013
Posts: 2,387
Likes: 707
2021 GLB250 FWD, 2023 GLA250 FWD, 2013 C250, 2015 GLK350, 2005 ML350SE, 2003 E320
A mechanic removed my oil filler cap with motor running , he showed me there was suction pulling it back down, he said it’s a bad PCV valve . Is this true ? I have no smoke or other symptom, oil changed at 5000m but bought used at 37000 miles.
I see nothing in the Glk maintenance manual on even checking the PCV valve going out to 140,000 miles. I’m getting it replaced today.
I see nothing in the Glk maintenance manual on even checking the PCV valve going out to 140,000 miles. I’m getting it replaced today.
Trending Topics
Junior Member
Joined: Dec 2022
Posts: 66
Likes: 23
2011 GLK350
It will absolutely be your PCV valve. Go to FCP euro and buy the package for that. It comes with the 3 cam plugs, oil breather cap, oil drip pan, oil separator, and 2 hoses!!
MB World Stories
The Best of Mercedes & AMG
8 Oddball Mercedes Ideas That Actually Made it to Production
Verdad Gallardo
Dubai Tuner Gives the Mercedes G-Class An Entirely New Look
Verdad Gallardo
Six Gift Ideas Your AMG Loving Dad or Grad Will Cherish
7 Craziest Things AMG Gas Ever Built
Verdad Gallardo
New Electric Mercedes-AMG GT 4-Door Coupe Unveiled: 10 Things You Need to Know
Verdad Gallardo
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)
Verdad Gallardo
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Super Member
Joined: Feb 2023
Posts: 728
Likes: 271
2011 GLK 350 4Matic
Thread Starter
MBWorld Fanatic!
Joined: Sep 2015
Posts: 2,605
Likes: 347
2013 glk 350
It’s finished , replaced, the hole a hose was attached to was enlarged naturally. No more sucking in the oil cap. Go check your Glk !
Last edited by Mmr1; Mar 16, 2023 at 05:47 PM.
MBWorld Fanatic!
Joined: Jun 2021
Posts: 1,970
Likes: 534
From: New Hampsha
'17 GLS450, '14 GLK250, Grandpa's Roadster
Thread Starter
MBWorld Fanatic!
Joined: Sep 2015
Posts: 2,605
Likes: 347
2013 glk 350
I’ll look for a photo, the photos you see are the top and it’s bolted down , on the bottom is a about 1” hole with rubber washer that connects to the motor, the rubber washer on the pvc wears, I guess from vibration and a leak develops. I threw the old one away. A poor design and poor placement as it’s like an 6-8 hour job to replace.
Thread Starter
MBWorld Fanatic!
Joined: Sep 2015
Posts: 2,605
Likes: 347
2013 glk 350
It’s just normal Wear and tear on the gasket, that is in the hole, on the bottom of the pvc. The wear will happen to all pvc and can’t be fixed . I should have worded it differently, and I can’t find a photo of the underside of pvc to show the gasket and hole . A vacuum check of the crankcase is needed to verify it’s bad . I don’t have the vacuum spec. But moderate pull on your oil cap , when you loosen and lift it, with motor running indicates an issue. A mild vacuum is normal. Its something that needs monitoring on old engines.
Junior Member
Joined: Dec 2022
Posts: 66
Likes: 23
2011 GLK350
I see what you mean!! I have a 2011 which is the M272 and it doesn't have the same PCV, similar but not the same. On mine I changed the PCV and the oil drip pan which is to what the PCV attaches to. I also changed the oil separator which sits on top of the engine drivers side along with it's hose. Which by the way when I took off the hose it actually came apart lol. Glad you got that fixed.
Senior Member
Joined: Feb 2020
Posts: 498
Likes: 154
From: Lac Ste. Marie, Quebec
2006 Alfa Romeo Brera, 2010 GLK350, 2018 BMW 640i GT, 1997 Subaru SVX, 2012 Moto Guzzi Norge GT8V
Thread Starter
MBWorld Fanatic!
Joined: Sep 2015
Posts: 2,605
Likes: 347
2013 glk 350
It’s really to bad it wasn’t made simple like a US 350 v8, a 3$ part and 3 minutes to replace. This thing was insane to get to. Remove the intake , high pressure oil pump and more ! That’s MB .
