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Pelican Technical Article:

Valve Cover Gasket Removal

Kerry Jonsson

Time:

2 hours2 hrs

Tab:

$50

Talent:

**

Tools:

4mm Allen head socket with ratchet and extension

Applicable Models:

Mercedes-Benz R129 (1990-02)

Parts Required:

Valve cover gasket

Hot Tip:

Tag the spark plug wires to identify the cylinders

Performance Gain:

Repair valve cover leak

While an engine runs combustion blow-by gases end up in the crankcase.  This creates internal pressure in the crankcase.  This combined with hot and cold cycles of your engine as you drive puts stress on gaskets and seals.  Your valve cover gaskets can dry out crack and leak oil.  Mercedes Benz uses a soft composite material for their valve cover gaskets.  It does last a long time but it can still dry out and leak.  This can create a burning smell under the hood as well as reduce the engine oil level between oil changers.  In this tech article we will go over all the necessary steps to remove your valve cover and replace your valve cover gaskets

In order to remove your valve cover gaskets you will need to remove the engine cover/air filter housing and your spark plug wire covers.  See our tech articles on removing engine covers and spark plug removal for these instructions.

This photo illustrates the right side cylinder bank.
Figure 1

This photo illustrates the right side cylinder bank. With the engine spark plug wire cover removed pull out each spark plug wire and place them over the intake manifold. See our tech article on spark plugs removal for further instructions.

On the right side cylinder toward the back remove the two 4 mm Allen head fasteners that hold a bracket that secures wiring to the valve cover.
Figure 2

On the right side cylinder toward the back remove the two 4 mm Allen head fasteners that hold a bracket that secures wiring to the valve cover. We have flipped the bracket out of the way and moved the wiring over the dipstick tube. This will give us more room to remove the valve cover.

Remove the nine 4 mm fasteners (green arrows) that hold down the valve cover.
Figure 3

Remove the nine 4 mm fasteners (green arrows) that hold down the valve cover. Make sure your Allen key or socket is fully seated in the fastener before you try to remove it, these screws are easily stripped. There is one fastener that is longer than the other end; there is another fastener that is shorter than the others. Note the location and make sure you put the fasteners back in the same place during reinstallation.

Working at the back of the valve cover, lift up the black sheathing (green arrow) that runs vacuum lines to the right side inner fender.
Figure 4

Working at the back of the valve cover, lift up the black sheathing (green arrow) that runs vacuum lines to the right side inner fender. This will add room and make it easier to pull off the valve cover.

Lift up on the valve cover to remove it from the cylinder head.
Figure 5

Lift up on the valve cover to remove it from the cylinder head. If itÂ's too tight find a safe corner and lever off with a prying tool.

With the right valve cover separated from the cylinder head lift it up and slide it in the direction of the blue arrows to remove it from the engine compartment.
Figure 6

With the right valve cover separated from the cylinder head lift it up and slide it in the direction of the blue arrows to remove it from the engine compartment.

Flip the valve cover over and start to peel away the rubber gasket (green arrow) and the rubber grommets (yellow arrows) that seal the spark pull the holes.
Figure 7

Flip the valve cover over and start to peel away the rubber gasket (green arrow) and the rubber grommets (yellow arrows) that seal the spark pull the holes. You can use a small amount of weather strip adhesive on the new gasket to hold in place while you install the valve cover. Slide the valve cover in the same way you took it out. Install and tighten down the fasteners. Position the wiring back on the valve cover and install the bracket that holds the wiring down. You can now route the vacuum lines around the back of the valve cover.

This photograph illustrates the left side valve cover.
Figure 8

This photograph illustrates the left side valve cover. Remove the 8 mm fastener that holds the fuel lines together (green arrow).

Remove the fuel lines (green arrows) from the fuel distributor using a 17 mm wrench and move them out of the way.
Figure 9

Remove the fuel lines (green arrows) from the fuel distributor using a 17 mm wrench and move them out of the way. This will make the valve cover easier to remove.

Remove the crankcase breather line from the valve cover by squeezing the clamp and pulling up on the hose.
Figure 10

Remove the crankcase breather line from the valve cover by squeezing the clamp and pulling up on the hose. These hoses are brittle and may break while removing. ItÂ's a good idea to replace them if youÂ're removing them.

Remove the nine 4 mm fasteners (green arrows) that hold down the valve cover.
Figure 11

Remove the nine 4 mm fasteners (green arrows) that hold down the valve cover. One fastener is longer than the other so remember where it goes during installation.

Lift up on the valve cover to separate it from the cylinder head.
Figure 12

Lift up on the valve cover to separate it from the cylinder head. You may have to use a prying tool and lever up on it if there is a tight seal. Find a safe corner to lever up from so you to not damage the sealing surface.

Slide the valve cover upward in the direction of the blue arrows to move it out of the engine compartment.
Figure 13

Slide the valve cover upward in the direction of the blue arrows to move it out of the engine compartment.

Flip over the valve cover over and peel away the outer gasket and inner grommets that seal the spark plug holes.
Figure 14

Flip over the valve cover over and peel away the outer gasket and inner grommets that seal the spark plug holes. You can use a small amount of weather strip adhesive on the new gasket to hold in place while you install the valve cover. Slide the valve cover in the same way you took it out. Install and tighten down the fasteners. Position the brake booster vacuum line back on the valve cover and install the fuel lines and bracket that hold them together. You can now route the vacuum lines around the back of the valve cover. Install the spark plug wire cover and the engine cover/air filter housing. Start the engine and make sure runs smooth.

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Comments and Suggestions:
Zeus101 Comments: On the right side valve cover there is 1 screw that is longer, and 1 that is shorter. Where does the short screw go? And I believe the valve cover has to be torqued to 9 NM.
October 14, 2016
  Followup from the Pelican Staff: I don't have the torque info to confirm.

I don't have a list of fastener locations. Best bet, thread them in by hand a few turns, confirm all fasteners are sticking out from the cover about the same distance before tightening.

- Nick at Pelican Parts
 
crazy ken Comments: what torques do you use on the valve cover bolts on 1999 sl500?
November 16, 2015
  Followup from the Pelican Staff: I don't have that info. I would grab a repair manual. It will have the procedure, special tools and torque specs.

Give our parts specialists a call at 1-888-280-7799. - Nick at Pelican Parts
 
Slim Comments: You make it look simple. Have a 99 SL 500, passenger side leaks just a bit, more like seeps.
Should I replace both sides at once?
1?? HOW DOES IT EFFECT PERFORMANCE?vovers off
anything else I should inspect while valve
September 15, 2014
  Followup from the Pelican Staff: I would replace both sides. Inspect the ignition wires and spark plugs while you are the area. - Nick at Pelican Parts  

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Page last updated: Wed 12/7/2016 02:28:25 AM