Intake Manifold Gasket and PCV valve DIY
Part numbers:
Intake manifold gaskets (2 needed): 159-141-05-80.
Intake manifold bolts (10 needed): 004-990-53-12.
PCV Valve: 156-010-03-70.
First, remove the airboxes and intake tubes. Then remove the Y-pipe. There is a tab on either side of the y-pipe that just basically lifts to release. I also removed the vacuum hose attached to it. You can see the tabs below.
Next, undo the vacuum hose at the front of the intake mani. It should just pull out.
Next, unhook all 4 plugs at the front of the intake manifold.
Remove the top connector on the PCV valve at the back of the intake mani on the passenger side. I think the one screw is a T30.
On the driver's side, undo the (I think this is what this is?) EGR tube from the back of the mani. There should just be 2 tabs you pinch and the tube slides right out.
Then cut the 6 zipties that are holding the wiring harness for the fuel injectors and disconnect the wiring harness from the injectors. I found that a small flathead screwdriver or a pick helped to undo the plugs in the tight space. You can see where the zipties are that I replaced. Also, disconnect the plug on the fuel rail, driver's side of the intake manifold.
Disconnect the intake air temp sensor at the back of the manifold. I forgot to take a pic, but it's the only sensor at the back of the intake manifold, driver's side that is on the oval intake part.
Next, undo the 10 T45 intake manifold bolts and throw them away. They are torque to yield. I found 2 of mine to be finger tight, likely the cause of my leaky intake manifold.
Then undo the line going to the fuel rail on the driver's side bulkhead. I used a 9/16 and an 11/16 wrench. Have a rag ready as a small amount of fuel will come out.
From there, the intake mani should lift off. I couldn't figure out how to get one vacuum line off the bottom, so I left it. There was plenty of room to take care of the PCV valve and the gaskets still.
With the intake mani out of the way, replace the PCV valve at the back of the motor. It just clips on. It took quite a bit of wiggling and force to get it off. I have no idea how people replace it without taking the mani off. Take the old one off. Pop the new one on.
Wipe any crap out of the heads with a rag and some brake clean. Mine were pretty clean after 70k miles.
Wipe the mating surfaces down and make sure everything is nice and clean. Pop the new gaskets on and set the manifold back down. Torque via the torque sequence below. Do the reverse of everything making sure to reconnect all the plugs and vacuum lines. Pop the airboxes back on and give it a start.
I hope this helps someone. It wasn't too hard. The intake mani is surprisingly light too. I'm no master mechanic and I took my time and did it all in about 2.5 hrs.
Last edited by chrisridebike8; Jul 17, 2016 at 12:13 PM.




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a decent sized job. This is something that many of us are capable of doing but may not without something like
this.
Last edited by 604 C63; Jul 17, 2016 at 11:33 AM.
would you please elaborate more when it whine exactly during high RPM or ideal ?
because I just cleaned mine and it wasn’t whining at all before and now I hear a low whine coming from the engine side, it come only at 1500 RPM and it is very low, you have to concentrate to hear it
Last edited by alamoudis2; Jul 18, 2016 at 08:13 AM.
Swiped from https://mbworld.org/forums/w211-amg/...-m156-e63.html


Going to do this next week. Have a P0171 Bank 1 too lean. Going to replace PCV and intake mani gaskets.
One question... what are those bolts next to the T45's. Do those not come out?
EDIT: Just noticed you pointed to one. Still no, I believe it's a bolt that secures the TB mount inside the IM.
Last edited by Jasonoff; Aug 11, 2016 at 06:36 PM.
I also can't get the vacuum hose off the Y intake tube, but there's enough slack just to push it on the side.
So far I found one of the intake bolts was finger loose.








