R500 M113.971
 

Hi all!

A bit of a lengthy story...

Got an 06' R500 with now 113k and to me it needs a head gasket on both banks. At 90k I had the heater core go, so replaced that(holy big job). After a while I began getting a small coolant leak somewhere(added coolant every month or so) and a small motoring noise from the engine(dieseling could also be the term). Thought from the noise I had a plug issue, did all 16 plugs.. same noise. No peanut butter oil cap, no mix of oil/coolant. So was kind of stumped, no performance issues or any detectable thing to point to a possible going head gasket. Got a strong 21mpg. Fast forward to 113k and after a 114 F degree day I had it overheat which ruptured a coolant hose from over pressure. Replace the entire cooling system down to the aux pump. I have codes on cyl 6&7 for mis fire. Engine smokes white and the idle is garbage unless I shut it off and restart fast to trick it. Constant bubbles in the coolant.

So...!

I am going to rip it apart and do a head gasket on both banks. Is there anything else any of you would think that could also be the cause? Coil issue? Intake?

Any tips or insight on this beast would be appreciated! i.e. do the intake manifold, valves, etcc while the head are out.

This is my first venture into MB so I don't know this engine at all. One guy local to me said these never blow head gaskets and to replace the motor... (not sure that's true and I have zero metal/alum in the pan or anywhere)

Last is the bolts... head bolts, would you replace with new? Also is it true the cam gear to cam bolt is one time use only and to get a new one?

Any help I appreciate to the utmost! If you have a diesel anything I can return the favor! :)

Search for user SK8215 on You Tube. He has multiple videos of M113K engine tear down and rebuild, along with many other things. This is not exactly your engine, but close enough.
he points out a few important weak points in this otherwise very strong design.

Good Luck.