SL/R231 '13 SL550 Check Valve Install - Tensioner bolts and Stepped vs Non-Stepped Valves

Mar 19, 2026 | 01:11 PM

ljuliano

Thread Starter

Junior Member

Joined: May 2009

Posts: 23

Likes: 3

From: USA

‘85 380SL, ‘03 SL500, ‘13 SL550

'13 SL550 Check Valve Install - Tensioner bolts and Stepped vs Non-Stepped Valves

I've found mixed answers on this: are the timing chain tensioner bolts re-usable? None of the TSBs call for one time use, but one document says so. They are magnetic so I assume steel and reusable.

Also, I have both 2780504000 and 2780503300, I can't fit a 5/16 drill bit into the bore and there is no sign of a step in my cylinder head. I'm over analyzing it but that's pretty much certain that I use the non-stepped 2780504000?

Mar 22, 2026 | 09:29 AM

jmattioni

Senior Member

Joined: Jan 2019

Posts: 476

Likes: 157

From: Philadelphia area

2014 SL65 AMG, 2018 S560

Do you have a copy of this NHTS bulletin?

MC-10167488-9999.pdf

There may also be an MB bulletin with more details about the repair.

However, the bulletin notes that the issue is not considered damaging to the engine.