606.912 engine intake manifold R&R - PeachParts Mercedes-Benz Forum

PRB0809 · #1 10-31-2013, 07:00 PM

Can some one please point me to a DIY for R&R the intake manifold on a 606.912 motor

Jeremy5848 · #2 10-31-2013, 08:09 PM

I don't think you really need a DIY as it's pretty simple but see some of the pictures in this thread. You need Torx bits rather than Allen bits to remove the manifold screws, that's the only unusual thing I remember.

Jeremy

winmutt · #3 10-31-2013, 09:23 PM

be careful on the torque specs....

connerm · #4 11-01-2013, 10:13 AM

x2 on torque specs.

Also, over time, the condition of the breather pipe connectors deteriorates. The rubber connectors get hard and crack. The rubber piece that attaches to the valve cover can crumble and dump pieces inside. The hard pipes don't usually need to be replaced.

You can reuse the long gasket, but they're not that expensive. I like to use a new one.

With the IM removed, you can also check the condition of the fuel return lines, vacuum lines, and resonator flaps. You can also replace the o-rings on the fuel pipes.

Good luck.

jake12tech · #5 11-01-2013, 11:16 AM

It's a MUST do on 606 you do the lines and o-rings. You will be on here in no time asking where it's leaking fuel.

the 606 likes to leak around those areas.

Jeremy5848 · #6 11-01-2013, 11:28 AM

And while you're in there, block the EGR valve and clean the crud out of the crossover and IM.

PRB0809 · #7 11-01-2013, 01:38 PM

My problem at the moment is being able to remove the cross over pipe. Do I need to remove the EGR valve and only the one bolt on top at the intake manifold?

connerm · #8 11-01-2013, 03:17 PM

On the Passenger side....I remove the two bolts that hold the x-over pipe to the bracket AND I remove the three bolts that hold the bracket to the head.
On the Driver side...I remove the long hex head bolt that holds the x-over to the plenum.

Back on the Passenger side...with my handy Red Devil model 4050 pry/scrape bar, I g.e.n.t.l.y. pry the x-over pipe from the egr housing exposing a connecter inside that has two large o-rings. One side is larger. Note orientation before you get it all apart.

Once the x-over is off, you can disconnect the vacuum line to the resonance flap. I made my vac hoses extra long which makes reassembly a lot easier. Lubricating the large o-rings on the x-over pipe connector makes reassembly a lot easier too, that and a big white rubber mallet.

Jeremy5848 · #9 11-01-2013, 05:02 PM

Quote:

Originally Posted by PRB0809

My problem at the moment is being able to remove the cross over pipe. Do I need to remove the EGR valve and only the one bolt on top at the intake manifold?

Follow conerm's instructions -- the EGR valve does not need to come off although if you do take it off it's easy to slip in a solid "gasket" and stop the nasty exhaust from polluting the intake manifold.

The connector with two large green o-rings has one side bigger than the other, you can't put it back together backwards. The larger side goes towards the air cleaner; it necks down to fit the crossover. Don't pinch an o-ring when reassembling -- be gentle!

Jeremy

PRB0809 · #10 11-02-2013, 09:01 AM

Jeremy thanks for the link and instructions, Connerm thanks as well for your input. X-Over pipe is out of the way. Got a few additional questions;
What is the tork sequence and NM for the intake manifold star bolts?
Where are the fuel line o-ring located that you recommend R&R?
It's the injector return jumpers you recomend to be replaced, correct?

Jeremy5848 · #11 11-02-2013, 12:08 PM

The torque sequence is not critical and I usually don't use a torque wrench on the IM screws. Just make sure you remembered to insert the gasket (no sealant) and that no hoses are missing, disconnected, or pinched. Then insert all of the screws and finger-tight. Since this is a normally-aspirated engine there is no pressure and the screws are threaded into aluminum so they don't have to be very tight. I use a small ratchet with the Torx bit and snug them all by feel. Someone should have a torque spec but I bet it's only about 15 ft-lbs.

Jeremy

connerm · #12 11-02-2013, 07:14 PM

15 ft/lbs is max. I get them all snug, then wiggle the im and tighten down the bolts. I like to start in the middle, but there isn't a prescribed order.

The o-rings are at every terminus of the fuel pipes. There are only two sizes. You will see a white horseshoe clip at each one. Push the horseshoe inward then pull the connector out. Lots of people pull the clip and break it. Be gentle and push it inward while you wiggle the pipe out.

There are lots of threads here indicating the size of the o-rings.

Replace the return lines (cloth covered grey or black rubber hose). Note that there is a plug in the return line closest to the firewall. Do not, do not, do not use a utility knife to remove the old return line from the injector nipple. A slight score on the nipple could cause a leak.