Rocker Arms replacement

A light rattling noise audible, especially around 1700 to 2000 rpm, somewhere on the right side of the engine... Probably cylinder 3 or 4 after first inspection.

Convinced to have this repaired by the workshop owner, I justed wanted to inspect visually in order to be able to pre-order the required components for repair to let it pass more quickly. As there was some time pressure... First opportunity at the workshop was for 7 August, while the next tour is scheduled from 15 August onwards... Waiting for repair as well as order duration, this could become tight...

Inspired by Kent Bergsma to inspect under the valve cover...

Inspired by Kent Bergsma from MercedesSource how you can do a lot of maintenance on your Mercedes yourself, I started to inspect myself... focusing on the right cylinder bank

After taking away the air intake with filter and removing the spark plug cables, I basically exposed the valve cover being hold down with 4 bolts.

Taking the cover off, at first there is no damage visible. Any damage to the rocker arms is hidden by the cam shaft pressing down the rocker arms.

Also on the other side, there is not much to see...

An overview of the right cylinder bank with cylinders 1 to 4 counted from front to rear (in this case right to left)

So, if I wanted to see more, I would need to remove the rocker arms, which requires special equipment. A 'spring compressor for valve spring':

Mercedes Valve Spring Compressor V8 , 4 & 6 Cylinder Engines Repair Tools

Used to depress valve springs for replacement of seals, stems, or valves. Mercedes #: 123 589 03 61 00 Engines: M114, 115, 116, 117, 130, 180 Applicable: V8 engines, 4 & 6 Cylinder engines.

Kommen Tools Inc.

Not the real Mercedes one, but close enough. However at Mercedes prices...

On Amazon you can find a much cheaper alternative:

FireAngels Compresseur de ressort de soupape pour voiture et moto : Amazon.com.be: Auto et moto

Depending on your desire to have the tool quickly, you can find different prices ranging from EUR 18 to EUR 36.

This is the way to arrange the tool. This way you can release the rocker arms easily.

So, here they are: the 8 rocker arms: for each cylinder one inlet and one outlet rocker arm.

There is the culprit: the surface of rocker arm 3A: the exhaust valve of cylinder 3

But 4 others were also damaged

So, these rocker arms needed to be replaced urgently. At SLS-HH-shop I have found the replacement part:

Rocker arm, all V8 116+117

SLS Online-ShopWebshop Team cvs.de

Individually packed

Unpacked

As I had seen 5 out of 8 rocket arms damaged, I decided to replace all 8 of them on the right cylinder bank...

Another opportunity...

Now the valve cover has been removed, it provides the perfect opportunity to look at an easy task that can avoid catastrophic engine damage. And for the price, there is no excuse not to do it: https://www.auto-onderdelen24.nl/febi-bilstein/1872819

The original ones from Mercedes, so you have the parts number...

Same package, rear side

The new plastic pieces mounted on the oil pipeline. Notice the tape at both ends: to ensure the end pieces will not fall off while installing on the cam shaft... See the old parts (broken when trying to remove them, so very brittle) above in the picture.

And as an extra precaution, I had covered the opening around the distribution chain, so really preventing anything to get into the engine!

Here the oil pipe line mounted on the camshaft before removing the tape. I can assure you I have removed the tape before closing the valve cover ;-)

Nice opportunity to clean the valve cover before replacing... Now half my engine looks good

The four bolts of the valve cover need to be torqued with 3 Nm...

Neiko 03727A 1/4-Inch Drive Beam Style Torque Wrench | 0-80 in/lb 9 Nm by Neiko : Amazon.com.be: Bricolage

Marque Neiko

The torque wrench used above

Somehow, the hardest part of the whole story: the mounting of the valve cover: after I had bolted it down cross-wise up to 3 Nm torque, the engine seemed to leak engine oil: after the engine gets hot on the exhaust pipes, the spilled oil during (dis)assembly started to smoke. However, after running for 10 minutes, the smoke still appeared... Damn!

So, in the end I had replaced the valve cover 7 (!) times with both new and old gasket, but nothing seemed to help. In the end I gave up and went to the workshop for advice. With smoke still appearing from the engine compartment, he proposed to use some liquid gasket for the valve cover. However, while explaining, we discovered that the smoke appearing from the exhausts was getting less and less...

Just to be sure, I had made 2 trips of 20 minutes to see that everything seemed to be fine, without touching any bolt...

I have done the maintenance on mileage 82.607 finishing on Sunday 04 August 2024 and at the time of writing (19 August), the mileage has increased to 83.055, so approx. 725 kilometers later. So, I can claim now the maintenance has been done successfully. Hurray!