jakwi

Hi all, Last weekend I swapped my crankcase vent valve and separator. I was prompted to do this by the oil in the airfilter housing and the vacuum on the engine when removing the oil cap.

From what I had read the issue is that crankcase vent. This was a major PITA to replace, but not impossible. Took me about 5 hours. I highly recommend purchasing an e10 ratchet wrench and and a set of non impact Esockets. (Female torx) It also would have been good to have the correct range of torque wrench. My inch pounder did ok, but was almost maxed out, and the other one I had was at the minimum end of the range and so not really accurate.

I also replaced the timing chain tensioners and installed check valves. The checkvalve press was $14.50 on Aliexpress, and only took a couple of weeks or so to get here. It worked perfectly.

Unfortunately after putting it all back together I found that the crankcase vacuum condition was still present. It doesn't seem to cause any issues. Should I be concerned? Is there another common cause?

As an aside the timing chain tensioners and check valves almost immediately resolved the rattle that I was experiencing

I did discover that my cam sensors are leaking oil, so I'll have to pull the upper intake again to swap them out once they arrive.

Altogether it was a 9 hour day, time well spent.

Cover the intake

Checkvalve press $12 on alliexpress

S-Prihadi

PCV while its name is Postive Crankcase Ventilation system, the actual working is your intake manifold is supposed to suck those bad piston blow-by air the PCV is managing.
Thus your engine will have and MUST have mild vacuum reading at the oil filler cap or the oil dipstick level.

Read here : https://mbworld.org/forums/e-class-w...sure-test.html

I would think minimum you must get at idling and proper engine operating temperature, minimum 20 millibar.

jakwi

Thank you for your reply!

I'm not sure how much vacuum is on it, but it's definitely more than any other vehicle I've ever owned. It is enough to be noticeable when I remove the oil cap. I'll have to setup a vacuum gauge to measure it. and thanks for the link I'm digging into that further.

jakwi

so your post from the link was very informative.

From what I can gather from your post normal vacuum is roughly 50 mbar or 0.73 psi negative.

I'll have to verify this later, but the oil cap opening is roughly 1.5 inches diameter, that is 7.07 sq inches (pi*r^2). Just guessing that it took no more than 1.5 pounds of force (from my calibrated arm) to break the seal. So 1.5/7.07 = 0.21 psi negative. I'll have to verify all of this, but it seems like I'm in spec.

It's just a little surprising to me given I've worked on a variety of cars over the years and never remember any force required to break the seal on an oil cap for any engine of any type.
Anyway thanks for taking the time to point me to your post.